HP 6125G User manual
HP 6125 Blade Switch Series
Layer 3 - IP Routing
Configuration Guide
Part number: 5998-3157
Software version: Release 2103
Document version: 6W100-20120907
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Contents
IP routing basics ··························································································································································· 1
Overview············································································································································································1
Routing table······································································································································································1
Dynamic routing protocols ···············································································································································2
Routing preference····························································································································································2
Load sharing······································································································································································3
Route backup·····································································································································································3
Route recursion··································································································································································3
Route redistribution ···························································································································································4
Displaying and maintaining a routing table ··················································································································4
Configuring static routing············································································································································ 6
Introduction ········································································································································································6
Static route ································································································································································6
Default route······························································································································································6
Static route configuration items·······························································································································6
Configuring a static route·················································································································································7
Configuring BFD for static routes·····································································································································8
BFD control mode·····················································································································································8
BFD echo mode ························································································································································9
Displaying and maintaining static routes ·······················································································································9
Static route configuration examples····························································································································· 10
Basic static route configuration example ············································································································ 10
BFD for static routes configuration example (direct next hop)·········································································· 12
BFD for static routes configuration example (indirect next hop)······································································· 14
Configuring RIP ··························································································································································17
Overview········································································································································································· 17
RIP route entries ····················································································································································· 17
RIP timers ································································································································································ 17
Routing loop prevention········································································································································ 17
RIP operation·························································································································································· 18
RIP versions ···························································································································································· 18
RIP message format ··············································································································································· 18
Supported RIP features·········································································································································· 20
Protocols and standards ······································································································································· 20
RIP configuration task list··············································································································································· 20
Configuring RIP basic functions ···································································································································· 21
Configuration prerequisites ·································································································································· 21
Enabling RIP and a RIP interface ························································································································· 21
Configuring the interface behavior ····················································································································· 22
Configuring a RIP version····································································································································· 22
Setting the DSCP value for RIP packets ··············································································································· 23
Configuring RIP route control········································································································································ 24
Configuring an additional routing metric ··········································································································· 24
Configuring RIPv2 route summarization·············································································································· 24
Disabling host route reception ····························································································································· 25
Advertising a default route ··································································································································· 25
Configuring inbound or outbound route filtering······························································································· 26
Configuring a priority for RIP······························································································································· 27
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Configuring RIP route redistribution····················································································································· 27
Tuning and optimizing RIP networks ···························································································································· 27
Configuring RIP timers··········································································································································· 28
Configuring split horizon and poison reverse···································································································· 28
Configuring the maximum number of ECMP routes ·························································································· 29
Enabling zero field check on incoming RIPv1 messages ·················································································· 29
Enabling source IP address check on incoming RIP updates············································································ 29
Configuring RIPv2 message authentication ········································································································ 30
Specifying a RIP neighbor ···································································································································· 30
Configuring RIP-to-MIB binding···························································································································· 31
Configuring the RIP packet sending rate ············································································································ 31
Configuring BFD for RIP················································································································································· 31
Single-hop echo detection mode ························································································································· 31
Bidirectional control detection mode··················································································································· 32
Displaying and maintaining RIP ··································································································································· 32
RIP configuration examples··········································································································································· 33
Configuring RIP version ········································································································································ 33
Configuring RIP route redistribution····················································································································· 34
Configuring an additional metric for a RIP interface························································································· 36
Configuring RIP to advertise a summary route··································································································· 38
Configuring BFD for RIP (single-hop echo detection mode)·············································································· 40
Configuring BFD for RIP (bidirectional control detection mode)······································································· 43
Troubleshooting RIP························································································································································ 47
No RIP updates received ······································································································································ 47
Route oscillation occurred ···································································································································· 47
Configuring OSPF ······················································································································································48
Overview········································································································································································· 48
Basic concepts ······················································································································································· 48
Area based OSPF network partition ··················································································································· 50
Router types···························································································································································· 53
OSPF network classification ································································································································· 54
DR and BDR ··························································································································································· 55
OSPF packet formats············································································································································· 56
Supported features ················································································································································ 64
Protocols and standards ······································································································································· 65
OSPF configuration task list ·········································································································································· 65
Enabling OSPF ······························································································································································· 66
Configuration prerequisites ·································································································································· 66
Configuration procedure ······································································································································ 67
Configuring OSPF areas ··············································································································································· 68
Configuration prerequisites ·································································································································· 68
Configuring a stub area ······································································································································· 68
Configuring an NSSA area·································································································································· 69
Configuring a virtual link······································································································································ 69
Configuring OSPF network types ································································································································· 70
Configuration prerequisites ·································································································································· 70
Configuring the broadcast network type for an interface················································································· 70
Configuring the NBMA network type for an interface ······················································································ 71
Configuring the P2MP network type for an interface························································································ 71
Configuring the P2P network type for an interface ··························································································· 72
Configuring OSPF route control ··································································································································· 72
Configuration prerequisites ·································································································································· 72
Configuring OSPF route summarization ············································································································· 73
Configuring OSPF inbound route filtering ·········································································································· 74
iii
Configuring ABR Type-3 LSA filtering ················································································································· 74
Configuring an OSPF cost for an interface ········································································································ 74
Configuring the maximum number of OSPF routes ··························································································· 75
Configuring the maximum number of ECMP routes ·························································································· 75
Configuring OSPF preference······························································································································ 76
Configuring OSPF route redistribution ················································································································ 76
Advertising a host route········································································································································ 78
Tuning and optimizing OSPF networks························································································································ 78
Configuration prerequisites ·································································································································· 78
Configuring OSPF packet timers·························································································································· 78
Specifying LSA transmission delay ······················································································································ 79
Specifying SPF calculation interval······················································································································ 80
Specifying the LSA arrival interval······················································································································· 80
Specifying the LSA generation interval ··············································································································· 80
Disabling interfaces from receiving and sending OSPF packets······································································ 81
Configuring stub routers ······································································································································· 81
Configuring OSPF authentication ························································································································ 82
Adding the interface MTU into DD packets········································································································ 82
Configuring the maximum number of external LSAs in LSDB ··········································································· 83
Enabling compatibility with RFC 1583··············································································································· 83
Logging neighbor state changes·························································································································· 83
Configuring OSPF network management ··········································································································· 84
Enabling message logging··································································································································· 84
Enabling the advertisement and reception of opaque LSAs ············································································· 84
Configuring OSPF to give priority to receiving and processing hello packets··············································· 85
Configuring the LSU transmit rate························································································································ 85
Setting the DSCP value for OSPF packets··········································································································· 86
Enabling OSPF ISPF ·············································································································································· 86
Configuring OSPF Graceful Restart······························································································································ 86
Configuring the OSPF GR Restarter····················································································································· 86
Configuring the OSPF GR Helper························································································································ 87
Triggering OSPF Graceful Restart························································································································ 88
Configuring BFD for OSPF ············································································································································ 88
Configuring control packet bidirectional detection ··························································································· 88
Configuring echo packet single-hop detection··································································································· 89
Displaying and maintaining OSPF······························································································································· 89
OSPF configuration examples ······································································································································ 90
Configuring OSPF basic functions······················································································································· 90
Configuring OSPF route redistribution ················································································································ 94
Configuring OSPF to advertise a summary route······························································································· 95
Configuring an OSPF stub area··························································································································· 98
Configuring an OSPF NSSA area·····················································································································100
Configuring OSPF DR election···························································································································102
Configuring OSPF virtual links ···························································································································106
Configuring OSPF Graceful Restart···················································································································108
Configuring route filtering ··································································································································110
Configuring BFD for OSPF ·································································································································113
Troubleshooting OSPF configuration ·························································································································116
No OSPF neighbor relationship established ····································································································116
Incorrect routing information ······························································································································116
Configuring BGP ····················································································································································· 117
BGP overview ·······························································································································································117
BGP messages formats········································································································································117
BGP path attributes ·············································································································································120
iv
BGP route selection ·············································································································································124
BGP and IGP synchronization····························································································································125
Settlements for problems in large scale BGP networks ···················································································126
BGP GR ································································································································································129
MP-BGP·································································································································································130
Protocols and standards ·····································································································································130
BGP configuration task list ··········································································································································131
Configuring BGP basic functions································································································································132
Configuration prerequisites ································································································································132
Creating a BGP connection································································································································132
Specifying the source interface for TCP connections·······················································································133
Allowing establishment of EBGP connection to an indirectly connected peer or peer group·····················134
Controlling route generation·······································································································································134
Configuration prerequisites ································································································································134
Injecting a local network ····································································································································134
Configuring BGP route redistribution ················································································································135
Enabling default route redistribution into BGP ·································································································135
Controlling route distribution and reception ·············································································································136
Configuration prerequisites ································································································································136
Configuring BGP route summarization ·············································································································136
Advertising a default route to a peer or peer group ·······················································································136
Configuring BGP route distribution/reception filtering policies ·····································································137
Enabling BGP and IGP route synchronization ·································································································139
Limiting prefixes received from a peer or peer group·····················································································139
Configuring BGP route dampening···················································································································140
Configuring a shortcut route·······························································································································140
Configuring BGP route attributes································································································································141
Configuration prerequisites ································································································································141
Specifying a preferred value for routes received·····························································································141
Configuring preferences for BGP routes ···········································································································141
Configuring the default local preference ··········································································································142
Configuring the MED attribute ···························································································································142
Configuring the NEXT_HOP attribute················································································································144
Configuring the AS_PATH attribute ···················································································································145
Tuning and optimizing BGP networks························································································································147
Configuration prerequisites ································································································································147
Configuring the BGP keepalive interval and holdtime ····················································································147
Configuring the interval for sending the same update ····················································································148
Configuring BGP soft-reset··································································································································148
Enabling the BGP ORF capability······················································································································149
Enabling 4-byte AS number suppression ··········································································································150
Setting the DSCP value for BGP packets···········································································································151
Enabling quick EBGP session reestablishment ·································································································151
Enabling MD5 authentication for TCP connections ·························································································152
Configuring BGP load balancing ······················································································································152
Forbiding session establishment with a peer or peer group···········································································152
Configuring a large scale BGP network····················································································································153
Configuration prerequisites ································································································································153
Configuring BGP peer groups ···························································································································153
Configuring BGP community······························································································································155
Configuring a BGP route reflector ·····················································································································155
Configuring a BGP confederation ·····················································································································156
Configuring BGP GR ···················································································································································157
Enabling trap································································································································································157
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Enabling logging of peer state changes····················································································································158
Configuring BFD for BGP ············································································································································158
Displaying and maintaining BGP·······························································································································158
Displaying BGP····················································································································································158
Resetting BGP connections ·································································································································160
Clearing BGP information ··································································································································160
BGP configuration examples ······································································································································160
BGP basic configuration example ·····················································································································160
BGP and IGP synchronization configuration example····················································································164
BGP load balancing configuration example ····································································································167
BGP community configuration example············································································································170
BGP route reflector configuration example·······································································································172
BGP confederation configuration example·······································································································174
BGP path selection configuration example·······································································································177
BGP GR configuration example·························································································································180
BFD for BGP configuration example ·················································································································181
Troubleshooting BGP ···················································································································································186
BGP peer relationship not established ··············································································································186
Configuring IPv6 static routing······························································································································· 188
Overview·······································································································································································188
IPv6 static routes features ············································································································································188
Default IPv6 route·························································································································································188
Configuring an IPv6 static route ·································································································································188
Displaying and maintaining IPv6 static routes··········································································································189
IPv6 static routing configuration example ·················································································································189
Configuring RIPng ··················································································································································· 192
Introduction to RIPng····················································································································································192
RIPng working mechanism··································································································································192
RIPng packet format ············································································································································193
RIPng packet processing procedure ··················································································································194
Protocols and standards ·····································································································································194
RIPng configuration task list ········································································································································194
Configuring RIPng basic functions······························································································································195
Configuring RIPng route control ·································································································································195
Configuring an additional routing metric ·········································································································195
Configuring RIPng route summarization ···········································································································196
Advertising a default route ·································································································································196
Configuring a RIPng route filtering policy·········································································································196
Configuring a priority for RIPng·························································································································197
Configuring RIPng route redistribution ··············································································································197
Tuning and optimizing the RIPng network·················································································································197
Configuring RIPng timers ····································································································································197
Configuring split horizon and poison reverse··································································································198
Configuring zero field check on RIPng packets ·······························································································199
Configuring the maximum number of ECMP routes ························································································199
Displaying and maintaining RIPng ·····························································································································199
RIPng configuration examples·····································································································································200
Configuring RIPng basic functions·····················································································································200
Configuring RIPng route redistribution ··············································································································202
Configuring OSPFv3··············································································································································· 206
Introduction to OSPFv3················································································································································206
OSPFv3 overview ················································································································································206
OSPFv3 packets···················································································································································206
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OSPFv3 LSA types···············································································································································207
OSPFv3 timers ·····················································································································································207
OSPFv3 features supported································································································································208
Protocols and standards ·····································································································································208
OSPFv3 configuration task list ····································································································································208
Enabling OSPFv3 ·························································································································································209
Configuration prerequisites ································································································································209
Enabling OSPFv3 ················································································································································209
Configuring OSPFv3 area parameters ······················································································································209
Configuration prerequisites ································································································································210
Configuring an OSPFv3 stub area ····················································································································210
Configuring an OSPFv3 virtual link···················································································································210
Configuring OSPFv3 network types···························································································································211
Configuration prerequisites ································································································································211
Configuring the OSPFv3 network type for an interface ··················································································211
Configuring an NBMA or P2MP neighbor·······································································································211
Configuring OSPFv3 routing information control ·····································································································212
Configuration prerequisites ································································································································212
Configuring OSPFv3 route summarization ·······································································································212
Configuring OSPFv3 inbound route filtering ····································································································212
Configuring an OSPFv3 cost for an interface ··································································································213
Configuring the maximum number of OSPFv3 ECMP routes ·········································································213
Configuring a priority for OSPFv3 ····················································································································214
Configuring OSPFv3 route redistribution··········································································································214
Tuning and optimizing OSPFv3 networks ·················································································································215
Configuration prerequisites ································································································································215
Configuring OSPFv3 timers································································································································215
Configuring a DR priority for an interface········································································································216
Ignoring MTU check for DD packets ·················································································································217
Disabling interfaces from receiving and sending OSPFv3 packets ·······························································217
Enabling the logging of neighbor state changes·····························································································217
Configuring OSPFv3 GR ·············································································································································217
Configuring GR Restarter····································································································································218
Configuring GR Helper·······································································································································218
Displaying and maintaining OSPFv3·························································································································219
OSPFv3 configuration examples ································································································································220
Configuring OSPFv3 areas ································································································································220
Configuring OSPFv3 DR election·······················································································································223
Configuring OSPFv3 GR ····································································································································226
Troubleshooting OSPFv3 configuration ·····················································································································228
No OSPFv3 neighbor relationship established································································································228
Incorrect routing information ······························································································································228
Configuring IPv6 BGP············································································································································· 229
IPv6 BGP overview·······················································································································································229
IPv6 BGP configuration task list··································································································································229
Configuring IPv6 BGP basic functions ·······················································································································230
Configuration prerequisites ································································································································230
Configuration guidelines ····································································································································230
Specifying an IPv6 BGP peer·····························································································································230
Injecting a local IPv6 route·································································································································231
Configuring a preferred value for routes from a peer or peer group····························································231
Specifying the source interface for establishing TCP connections ·································································232
Allowing the establishment of an indirect EBGP connection ··········································································232
Configuring a description for an IPv6 peer or peer group·············································································232
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Disabling session establishment to an IPv6 peer or peer group ····································································233
Logging IPv6 peer or peer group state changes······························································································233
Controlling route distribution and reception ·············································································································233
Configuration prerequisites ································································································································234
Configuring IPv6 BGP route redistribution········································································································234
Configuring IPv6 BGP route summarization·····································································································234
Advertising a default route to an IPv6 peer or peer group·············································································234
Configuring outbound route filtering·················································································································235
Configuring inbound route filtering ···················································································································236
Configuring IPv6 BGP and IGP route synchronization····················································································236
Configuring route dampening····························································································································237
Configuring IPv6 BGP route attributes ·······················································································································237
Configuration prerequisites ································································································································237
Configuring IPv6 BGP preference and default LOCAL_PREF and NEXT_HOP attributes ····························237
Configuring the MED attribute ···························································································································238
Configuring the AS_PATH attribute ···················································································································238
Tuning and optimizing IPv6 BGP networks ···············································································································239
Configuration prerequisites ································································································································240
Configuring IPv6 BGP timers······························································································································240
Configuring IPv6 BGP soft reset·························································································································240
Enabling the IPv6 BGP ORF capability ·············································································································241
Enabling 4-byte AS number suppression ··········································································································242
Setting the DSCP value for IPv6 BGP packets ··································································································243
Configuring the maximum number of ECMP routes ························································································243
Enabling MD5 authentication for TCP connections ·························································································243
Configuring a large-scale IPv6 BGP network············································································································244
Configuration prerequisites ································································································································244
Configuring IPv6 BGP peer group·····················································································································244
Configuring IPv6 BGP community ·····················································································································245
Configuring an IPv6 BGP route reflector···········································································································246
Displaying and maintaining IPv6 BGP·······················································································································247
Displaying BGP····················································································································································247
Resetting IPv6 BGP connections·························································································································248
Clearing IPv6 BGP information··························································································································248
IPv6 BGP configuration examples ······························································································································248
IPv6 BGP basic configuration example·············································································································249
IPv6 BGP route reflector configuration example ······························································································251
Troubleshooting IPv6 BGP configuration ···················································································································252
IPv6 BGP peer relationship not established······································································································252
Configuring routing policies··································································································································· 253
Introduction to routing policy ······································································································································253
Routing policy application··································································································································253
Routing policy implementation···························································································································253
Filters·····································································································································································253
Defining filters·······························································································································································255
Configuration prerequisites ································································································································255
Defining an IP prefix list······································································································································255
Defining an AS path list······································································································································256
Defining a community list ···································································································································256
Defining an extended community list ················································································································257
Configuring a routing policy·······································································································································257
Configuration prerequisites ································································································································257
Creating a routing policy ···································································································································257
Defining if-match clauses ····································································································································258
viii
Defining apply clauses········································································································································259
Defining a continue clause ·································································································································260
Displaying and maintaining the routing policy·········································································································261
Routing policy configuration examples······················································································································261
Applying a routing policy to IPv6 route redistribution·····················································································261
Applying a routing policy to filter received BGP routes··················································································263
Troubleshooting routing policy configuration ···········································································································265
IPv4 routing information filtering failure············································································································265
IPv6 routing information filtering failure············································································································266
Configuring MCE ···················································································································································· 267
MCE overview ······························································································································································267
MPLS L3VPN overview········································································································································267
MPLS L3VPN concepts ········································································································································268
Multi-VPN-instance CE ········································································································································270
How MCE works ·················································································································································270
Configuring routing on an MCE·································································································································271
Route exchange between an MCE and a VPN site·························································································271
Route exchange between an MCE and a PE ···································································································272
Configuring an MCE ···················································································································································273
Configuring VPN instances ································································································································273
Configuring routing on an MCE·································································································································275
Configuration prerequisites ································································································································275
Configuring routing between MCE and VPN site····························································································275
Configuring routing between MCE and PE ······································································································280
Resetting BGP connections ··········································································································································283
Displaying and maintaining MCE······························································································································283
MCE configuration examples ·····································································································································285
Using OSPF to advertise VPN routes to the PE·································································································285
Using BGP to advertise VPN routes to the PE···································································································289
Configuring policy-based routing ·························································································································· 293
Introduction to PBR ·······················································································································································293
Configuring PBR ···························································································································································293
Configuring a QoS policy ··································································································································293
Applying the QoS policy····································································································································294
Displaying and maintaining PBR configuration ········································································································294
PBR configuration examples········································································································································295
IPv4 PBR configuration example························································································································295
IPv6 PBR configuration example························································································································296
Support and other resources ·································································································································· 298
Contacting HP ······························································································································································298
Subscription service ············································································································································298
Related information······················································································································································298
Documents····························································································································································298
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Conventions ··································································································································································299
Index ········································································································································································ 301
1
IP routing basics
Overview
IP routing directs the forwarding of IP packets on routers based on a routing table. This book focuses on
unicast routing protocols. For more information about multicast routing protocols, see IP Multicast
Configuration Guide.
The term "router" in this chapter refers to both routers and Layer 3 switches.
The types of interfaces that appear in any figures other than the network diagrams for configuration
examples are for illustration only. Some of them might be unavailable on your switch.
Routing table
A router maintains at least two routing tables: one global routing table and one forwarding information
base (FIB). The FIB table contains only the optimal routes, and the global routing table contains all routes.
The router uses the FIB table to forward packets. For more information about the FIB table, see Layer 3—IP
Services Configuration Guide.
Routes can be classified by different criteria, as shown in Table 1.
Table 1 Categories of routes
Criterion Categories
Destination •Network route—Destination is a network. The subnet mask is less than 32 bits.
•Host route—Destination is a host. The subnet mask is 32 bits.
Whether the
destination is directly
connected
•Direct route—Destination is directly connected.
•Indirect route—Destination is indirectly connected.
Origin
•Direct route—A direct route is discovered by the data link protocol on an interface,
and is also called an "interface route."
•Static route—A static route is manually configured by an administrator.
•Dynamic route—A dynamic route is dynamically discovered by a routing protocol.
Static routes are easy to configure and require less system resources. They work well in small and stable
networks. In networks where topology changes may occur frequently, using a dynamic routing protocol
is better.
To display brief information about a routing table, use the display ip routing-table command:
<Sysname> display ip routing-table
Routing Tables: Public
Destinations : 7 Routes : 7
Destination/Mask Proto Pre Cost NextHop Interface
1.1.1.0/24 Direct 0 0 1.1.1.1 Vlan11
2.2.2.0/24 Static 60 0 12.2.2.2 Vlan12
2
80.1.1.0/24 OSPF 10 2 80.1.1.1 Vlan13
…
A route entry includes the following key items:
•Destination—IP address of the destination host or network.
•Mask—Mask length of the IP address.
•Pre—Preference of the route. Among routes to the same destination, the one with the highest
preference is optimal.
•Cost—If multiple routes to a destination have the same preference, the one with the smallest cost is
the optimal route.
•NextHop—Next hop.
•Interface—Output interface.
Dynamic routing protocols
Dynamic routing protocols dynamically collect and report reachability information to adapt to topology
changes. They are suitable for large networks.
Compared with static routing, dynamic routing protocols require more resources, and are complicated to
configure.
Dynamic routing protocols can be classified based on different criteria, as shown in Table 2:
Table 2 Dynamic routing protocols
Criterion Categories
Optional scope
•Interior gateway protocols (IGPs)—Work within an AS. Examples include RIP, and
OSPF.
•Exterior gateway protocols (EGPs)—Work between ASs. The most popular one is
BGP.
Routing algorithm
•Distance-vector protocols—RIP and BGP. BGP is also considered a path-vector
protocol.
•Link-state protocols—OSPF.
Destination address
type
•Unicast routing protocols—RIP, OSPF, and BGP.
•Multicast routing protocols—PIM-SM and PIM-DM.
IP version
•IPv4 routing protocols—RIP, OSPF, and BGP.
•IPv6 routing protocols—RIPng, OSPFv3, and IPv6 BGP.
NOTE:
A
n AS refers to a group of routers sharing the same routing policy and working under the same
administration.
Routing preference
Different routing protocols can find different routes to the same destination. However, not all of those
routes are optimal. For route selection, routing protocols, direct routes, and static routes are assigned
different preferences. The route with the highest preference is preferred.
3
The preference of a direct route is always 0 and cannot be changed. You can manually configure
preferences for any other route type. Each static route can be configured with a different preference. The
following table lists the types of routes and the default preferences. The smaller the preference value, the
higher the preference.
Table 3 Route types and their default route preferences
Routing approach Preference
Direct route 0
OSPF 10
Static route 60
RIP 100
OSPF ASE 150
OSPF NSSA 150
IBGP 255
EBGP 255
Unknown (route from an untrusted source) 256
Load sharing
A routing protocol can be configured with multiple equal-cost routes to the same destination. These routes
have the same preference and will all be used to accomplish load sharing if there is no route with a
higher preference available.
Static routing/IPv6 static routing, RIP/RIPng, OSPF/OSPFv3, and BGP/IPv6 BGP supports ECMP load
sharing.
Route backup
Route backup can improve network availability. Among multiple routes to the same destination, the route
with the highest preference is the main route and all others are backup routes.
The router forwards matching packets through the main route. When the main route fails, the route with
the highest preference among the backup routes is selected to forward packets. When the main route
recovers, the router uses it to forward packets.
Route recursion
To use a BGP route, static route (that is configured with a next hop but with no output interface), or RIP
route that has an indirectly-connected next hop, a router must perform route recursion to find the outgoing
interface to reach the next hop.
Link-state routing protocols, such as OSPF, do not need route recursion, because they obtain
directly-connected next hops through route calculation.
4
Route redistribution
Route redistribution enables routing protocols to learn route information from each other. A dynamic
routing protocol can redistribute routes from other protocols including direct routes and static routes. For
more information, see the respective chapters on those routing protocols in this configuration guide.
Displaying and maintaining a routing table
Task Command Remarks
Display information about the
routing table.
display ip routing-table [ vpn-instance
vpn-instance-name ] [ verbose ] [ | { begin
|exclude |include } regular-expression ]
Available in any view
Display information about routes
permitted by an IPv4 basic ACL.
display ip routing-table [ vpn-instance
vpn-instance-name ] acl acl-number
[ verbose ] [ |{ begin | exclude |
include } regular-expression ]
Available in any view
Display information about routes to
the specified destination.
display ip routing-table [ vpn-instance
vpn-instance-name ] ip-address [ mask |
mask-length ] [ longer-match ] [ verbose ]
[ |{ begin | exclude | include }
regular-expression ]
Available in any view
Display information about routes
with destination addresses in the
specified range.
display ip routing-table [ vpn-instance
vpn-instance-name ] ip-address1 { mask |
mask-length } ip-address2 { mask |
mask-length } [ verbose ] [ |{ begin |
exclude | include } regular-expression ]
Available in any view
Display routing information
permitted by an IPv4 prefix list.
display ip routing-table [ vpn-instance
vpn-instance-name ] ip-prefix
ip-prefix-name [ verbose ] [ |{ begin |
exclude | include } regular-expression ]
Available in any view
Display routes of a routing
protocol.
display ip routing-table [ vpn-instance
vpn-instance-name ] protocol protocol
[ inactive | verbose ] [ |{ begin | exclude
| include } regular-expression ] [ |{ begin
| exclude | include } regular-expression ]
[ |{ begin | exclude | include }
regular-expression ]
Available in any view
Display statistics about the routing
table.
display ip routing-table [ vpn-instance
vpn-instance-name ] statistics [ |{ begin |
exclude | include } regular-expression ]
Available in any view
Clear statistics for the routing table.
reset ip routing-table statistics protocol
[ vpn-instance vpn-instance-name ]
{protocol |all }
Available in user view
Display IPv6 routing table
information.
display ipv6 routing-table [ vpn-instance
vpn-instance-name ] [ verbose ] [ |{ begin
| exclude | include } regular-expression ]
Available in any view
5
Task Command Remarks
Display routing information
permitted by an IPv6 ACL.
display ipv6 routing-table [ vpn-instance
vpn-instance-name ] acl acl6-number
[ verbose ] [ |{ begin | exclude |
include } regular-expression ]
Available in any view
Display routing information for a
specified destination IPv6 address.
display ipv6 routing-table [ vpn-instance
vpn-instance-name ] ipv6-address
prefix-length [ longer-match ] [ verbose ]
[ |{ begin | exclude | include }
regular-expression ]
Available in any view
Display IPv6 routing information
for an IPv6 address range.
display ipv6 routing-table [ vpn-instance
vpn-instance-name ] ipv6-address1
prefix-length1 ipv6-address2
prefix-length2 [ verbose ] [ |{ begin |
exclude | include } regular-expression ]
Available in any view
Display routing information
permitted by an IPv6 prefix list.
display ipv6 routing-table [ vpn-instance
vpn-instance-name ] ipv6-prefix
ipv6-prefix-name [ verbose ] [ |{ begin |
exclude | include } regular-expression ]
Available in any view
Display IPv6 routing information of
a routing protocol.
display ipv6 routing-table [ vpn-instance
vpn-instance-name ] protocol protocol
[ inactive | verbose ] [ |{ begin | exclude
| include } regular-expression ]
Available in any view
Display IPv6 routing statistics.
display ipv6 routing-table [ vpn-instance
vpn-instance-name ] statistics [ |{ begin |
exclude | include } regular-expression ]
Available in any view
Clear specified IPv6 routing
statistics.
reset ipv6 routing-table statistics protocol
[ vpn-instance vpn-instance-name ]
{ protocol |all }
Available in user view
6
Configuring static routing
Introduction
Static route
Static routes are manually configured. If a network's topology is simple, you only need to configure static
routes for the network to work properly. The proper configuration and usage of static routes can improve
network performance and ensure bandwidth for important network applications.
Static routes cannot adapt to network topology changes. If a fault or a topological change occurs in the
network, the relevant routes will be unreachable and the network breaks. When this happens, the
network administrator must modify the static routes manually.
The term "router" in this chapter refers to both routers and Layer 3 switches.
Default route
Without a default route, a packet that does not match any routing entries is discarded.
A default route is used to forward packets that do not match any routing entry. It can be configured in
either of the following ways:
•The network administrator can configure a default route with both the destination and mask being
0.0.0.0. The router forwards any packet whose destination address fails to match any entry in the
routing table to the next hop of the default static route.
•Some dynamic routing protocols, such as OSPF, and RIP, can also generate a default route. For
example, an upstream router running OSPF can generate a default route and advertise it to other
routers, which install the default route with the next hop being the upstream router.
Static route configuration items
Before you configure a static route, you must know the following concepts:
•Destination address and mask
In the ip route-static command, an IPv4 address is in dotted decimal notation. A mask can be
either in dotted decimal format or in the form of mask length—the number of consecutive 1s in the
mask.
•Output interface and next hop address
When you configure a static route, specify either the output interface, next hop address, or both
depending on the specific occasion. The next hop address cannot be a local interface IP address;
otherwise, the route configuration will not take effect.
Each route lookup operation has to find the next hop to resolve the destination link layer address.
Follow these guidelines when you specify the output interface:
{If the output interface is a Null 0 interface, no next hop address is required.
{If you specify a broadcast interface (such as a VLAN interface) as the output interface, you must
specify the corresponding next hop for the output interface.
7
•Other attributes
You can configure different priorities for different static routes so that route management policies
can be more flexible. For example, specifying the same priority for different routes to the same
destination enables load sharing, but specifying different priorities for these routes enables route
backup.
Configuring a static route
Before you configure a static route, complete the following tasks:
•Configure the physical parameters for related interfaces.
•Configure the link-layer attributes for related interfaces.
•Configure the IP addresses for related interfaces.
Follow these guidelines when you configure a static route:
•The next hop address cannot be the IP address of a local interface (such as Ethernet interface and
VLAN interface). Otherwise, the static route does not take effect.
•If you do not specify the preference when you configure a static route, the default preference applies.
Reconfiguring the default preference applies only to newly created static routes.
•You can flexibly control static routes by configuring tag values and using the tag values in the
routing policy.
•If the destination IP address and mask are both configured as 0.0.0.0 with the ip route-static
command, then the route is the default route.
•For more information about track, see High Availability Configuration Guide.
To configure a static route:
Ste
p
Command
Remarks
1. Enter system view. system-view N/A
2. Configure a static
route.
•Approach 1:
ip route-static dest-address { mask |
mask-length } { next-hop-address [ track
track-entry-number ] | interface-type
interface-number [ next-hop-address ] |
vpn-instance d-vpn-instance-name
next-hop-address [ track track-entry-number ] }
[ preference preference-value ] [ tag tag-value ]
[ permanent ] [ description description-text ]
•Approach 2:
ip route-static vpn-instance
s-vpn-instance-name&<1-6> dest-address
{ mask | mask-length } { next-hop-address
[ public ] [ track track-entry-number ] |
interface-type interface-number
[ next-hop-address ] | vpn-instance
d-vpn-instance-name next-hop-address [ track
track-entry-number ] } [ preference
preference-value ] [ tag tag-value ]
[ permanent ] [ description description-text ]
Use either approach.
By default, preference for
static routes is 60, tag is 0,
and no description
information is configured.
Do not specify the permanent
and track keywords
simultaneously.
If the output interface is down,
the permanent static route is
still active.
8
Ste
p
Command
Remarks
3. Configure the
default preference
for static routes.
ip route-static default-preference
default-preference-value
Optional.
60 by default.
Configuring BFD for static routes
Bidirectional forwarding detection (BFD) provides a general-purpose, standard, medium-, and
protocol-independent fast failure detection mechanism. It can uniformly and quickly detect the failures of
the bidirectional forwarding paths between two routers for protocols, such as routing protocols. For more
information about BFD, see High Availability Configuration Guide.
A dynamic routing protocol notifies BFD of its neighbor information. BFD uses such information to
establish sessions with neighbors by sending BFD control packets. Static routing has no neighbor
discovery mechanism. This section describes how static routing implements BFD.
BFD control mode
To use BFD bidirectional control detection between two devices, you must enable BFD control mode for
each device's static route destined to the peer.
To configure a static route and enable BFD control mode for it, specify an output interface and a direct
next hop, or specify an indirect next hop and a specific BFD packet source address for the static route.
To configure BFD control mode for a static route (direct next hop):
Ste
p
Command
Remarks
1. Enter system view. system-view N/A
2. Configure BFD
control mode for a
static route.
•Approach 1:
ip route-static dest-address { mask |mask-length }
interface-type interface-number next-hop-address bfd
control-packet [ preference preference-value ] [ tag
tag-value ] [ description description-text ]
•Approach 2:
ip route-static vpn-instance s-vpn-instance-name&<1-6>
dest-address { mask | mask-length } interface-type
interface-number next-hop-address bfd control-packet
[ preference preference-value ] [ tag tag-value ] [ description
description-text ]
Use either
approach.
To configure BFD control mode for a static route (indirect next hop):
Ste
p
Command
Remarks
1. Enter system view. system-view N/A
9
Ste
p
Command
Remarks
2. Configure BFD
control mode for a
static route.
•Approach 1:
ip route-static dest-address { mask | mask-length }
next-hop-address bfd control-packet bfd-source ip-address
[ preference preference-value ] [ tag tag-value ] [ description
description-text ]
•Approach 2:
ip route-static vpn-instance s-vpn-instance-name&<1-6>
dest-address {mask | mask-length } next-hop-address bfd
control-packet bfd-source ip-address [ preference
preference-value ] [ tag tag-value ] [ description
description-text ]
Use either
command.
BFD echo mode
IMPORTANT:
•Enabling BFD for a flapping route could worsen the situation. Therefore, use it with caution.
•Do not use BFD for a static route with the output interface having the spoofing attribute.
With BFD echo mode enabled for a static route, the local device sends BFD echo packets to the peer,
which loops it back to test the link. For the echo mode, only one end needs to establish the BFD session,
and the source address of echo packets must be configured.
To configure BFD echo mode for static routes:
Ste
p
Command
Remarks
1. Enter system view. system-view N/A
2. Configure the
source address of
echo packets.
bfd echo-source-ip ip-address
Not configured by default.
For more information about
this command, see High
Availability Command
Reference.
3. Enable BFD echo
mode for static
routes.
•Approach 1:
ip route-static dest-address { mask |
mask-length } interface-type interface-number
next-hop-address bfd echo-packet [ preference
preference-value ] [ tag tag-value ] [ description
description-text ]
•Approach 2:
ip route-static vpn-instance
s-vpn-instance-name&<1-6> dest-address {mask
|mask-length } interface-type interface-number
next-hop-address bfd echo-packet [ preference
preference-value ] [ tag tag-value ] [ description
description-text ]
Use either approach.
Displaying and maintaining static routes
10
Task Command
Remarks
Display information of static
routes.
display ip routing-table protocol static [ inactive |
verbose ] [ |{ begin | exclude | include }
regular-expression ]
Available in any
view
Delete all the static routes. delete [ vpn-instance vpn-instance-name ]
static-routes all
Available in
system view
For more information about the display ip routing-table protocol static [ inactive | verbose ] [ |{ begin
| exclude | include } regular-expression ] command, see Layer 3—IP Routing Command Reference.
Static route configuration examples
Basic static route configuration example
Network requirements
Configure static routes in Figure 1 for interconnection between any two hosts.
Figure 1 Network diagram
Configuration procedure
1. Configure IP addresses for interfaces. (Details not shown.)
2. Configure static routes:
# Configure a default route on Switch A.
<SwitchA> system-view
[SwitchA] ip route-static 0.0.0.0 0.0.0.0 1.1.4.2
# Configure two static routes on Switch B.
<SwitchB> system-view
[SwitchB] ip route-static 1.1.2.0 255.255.255.0 1.1.4.1
[SwitchB] ip route-static 1.1.3.0 255.255.255.0 1.1.5.6
# Configure a default route on Switch C.
<SwitchC> system-view
[SwitchC] ip route-static 0.0.0.0 0.0.0.0 1.1.5.5
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