Cisco NCS 5500 Series User manual

Routing Configuration Guide for Cisco NCS 5500 Series Routers, IOS
XR Release 6.3.x
First Published: 2017-09-01
Last Modified: 2018-03-01
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CONTENTS
Preface xi
PREFACE
Changes to This Document xi
Obtaining Documentation and Submitting a Service Request xi
New and Changed Routing Features 1
CHAPTER 1
New and Changed Routing Features 1
Implementing IS-IS 3
CHAPTER 2
Enable IS-IS and Configure Level 1 or Level 2 Routing 3
Single-Topology IPv6 5
Configure Single Topology for IS-IS 5
Set SPF Interval for a Single-Topology Configuration 10
Customize Routes for IS-IS 12
Set Priority for Adding Prefixes to RIB 15
IS-IS Interfaces 16
Tag IS-IS Interface Routes 16
Limit LSP Flooding 19
Control LSP Flooding for IS-IS 19
IS-IS Authentication 23
Configure Authentication for IS-IS 23
Configure Keychains for IS-IS 25
Nonstop Forwarding 26
Configure Nonstop Forwarding for IS-IS 27
ISIS NSR 29
Configuring ISIS-NSR 29
Multiprotocol Label Switching Traffic Engineering 31
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Configure MPLS Traffic Engineering for IS-IS 31
MPLS TE Forwarding Adjacency 33
Tune Adjacencies for IS-IS 33
MPLS Label Distribution Protocol IGP Synchronization 36
Configuring MPLS LDP IS-IS Synchronization 36
IS-IS Overload Bit Avoidance 37
Configure IS-IS Overload Bit Avoidance 38
Configuring Global Weighted SRLG Protection 39
References for IS-IS 41
IS-IS Functional Overview 41
Default Routes 41
Overload Bit on Router 42
Overload Bit Configuration During Multitopology Operation 42
Attached Bit on an IS-IS Instance 42
IS-IS Support for Route Tags 42
Flood Blocking on Specific Interfaces 43
Maximum LSP Lifetime and Refresh Interval 43
Mesh Group Configuration 43
Multi-Instance IS-IS 43
Label Distribution Protocol IGP Auto-configuration 43
MPLS LDP-IGP Synchronization Compatibility with LDP Graceful Restart 44
MPLS LDP-IGP Synchronization Compatibility with IGP Nonstop Forwarding 44
Implementing OSPF 45
CHAPTER 3
Prerequisites for Implementing OSPF 46
Enable OSPF 46
Verify OSPF Configuration and Operation 48
Stub Area 51
Not-so-Stubby Area 51
Configure Stub and Not-So-Stubby Area Types 51
Neighbors and Adjacency for OSPF 54
Configure Neighbors for Nonbroadcast Networks 54
Authentication Strategies 58
Configure Authentication at Different Hierarchical Levels for OSPF Version 2 58
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Contents

Control Frequency That Same LSA Is Originated or Accepted for OSPF 61
Virtual Link and Transit Area for OSPF 63
Create Virtual Link 64
Summarize Subnetwork LSAs on OSPF ABR 68
Route Redistribution for OSPF 71
Redistribute Routes into OSPF 71
Nonstop Forwarding for OSPF Version 2 73
Configure Nonstop Forwarding Specific to Cisco for OSPF Version 2 74
OSPF Shortest Path First Throttling 76
Configure OSPF Shortest Path First Throttling 77
Graceful Restart for OSPFv3 79
Configure OSPFv3 Graceful Restart 79
Display Information About Graceful Restart 81
Warm Standby and Nonstop Routing for OSPF Version 2 81
Enable Nonstop Routing for OSPFv2 82
Warm Standby and Nonstop Routing for OSPF Version 3 82
Enable Nonstop Routing for OSPFv3 83
OSPFv2OSPF SPF Prefix Prioritization 83
Configure OSPFv2 OSPF SPF Prefix Prioritization 85
Configure OSPF as a Provider Edge to Customer Edge (PE-CE) Protocol 88
Create Multiple OSPF Instances (OSPF Process and a VRF) 90
Label Distribution Protocol IGP Auto-configuration for OSPF 92
Configure Label Distribution Protocol IGP Auto-configuration for OSPF 92
Configure LDP IGP Synchronization: OSPF 93
OSPF Authentication Message Digest Management 95
Configure Authentication Message Digest Management for OSPF 95
GTSM TTL Security Mechanism for OSPF 98
Configure Generalized TTL Security Mechanism (GTSM) for OSPF 99
References for OSPF 101
OSPF Functional Overview 101
Comparison of Cisco IOS XR Software OSPFv3 and OSPFv2 102
OSPF Hierarchical CLI and CLI Inheritance 103
OSPF Routing Components 103
Autonomous Systems 104
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Areas 104
Routers 105
OSPF Process and Router ID 105
Supported OSPF Network Types 106
Route Authentication Methods for OSPF 106
Plain Text Authentication 106
MD5 Authentication 106
Key Rollover 107
OSPF FIB Download Notification 107
Designated Router (DR) for OSPF 107
Default Route for OSPF 107
Link-State Advertisement Types for OSPF Version 2 107
Link-State Advertisement Types for OSPFv3 108
Passive Interface 109
Modes of Graceful Restart Operation 110
Restart Mode 110
Helper Mode 110
Protocol Shutdown Mode 111
Load Balancing in OSPF Version 2 and OSPFv3 112
Path Computation Element for OSPFv2 112
Management Information Base (MIB) for OSPFv3 112
VRF-lite Support for OSPFv2 113
OSPFv3 Timers Update 113
Implementing and Monitoring RIB 115
CHAPTER 4
Verify RIB Configuration Using Routing Table 115
Verify Networking and Routing Problems 116
Disable RIB Next-hop Dampening 118
Enable RCC and LCC On-demand Scan 119
Enable RCC and LCC Background Scan 120
References for RIB 122
RIB Data Structures in BGP and Other Protocols 122
RIB Administrative Distance 122
RIB Statistics 123
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RIB Quarantining 124
Route and Label Consistency Checker 124
Implementing Routing Policy 127
CHAPTER 5
Restrictions for Implementing Routing Policy 127
Define Route Policy 128
Attach Routing Policy to BGP Neighbor 129
Modify Routing Policy Using Text Editor 130
References for Routing Policy 133
Routing Policy Language 134
Routing Policy Language Overview 134
Routing Policy Language Structure 134
Routing Policy Language Components 141
Routing Policy Language Usage 142
Policy Definitions 144
Parameterization 145
Parameterization at Attach Points 146
Global Parameterization 146
Semantics of Policy Application 147
Boolean Operator Precedence 147
Multiple Modifications of Same Attribute 147
When Attributes Are Modified 148
Default Drop Disposition 149
Control Flow 149
Policy Verification 150
Policy Statements 152
Remark 152
Disposition 152
Action 154
If 154
Boolean Conditions 155
apply 157
Attach Points 157
BGP Policy Attach Points 157
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Contents

OSPF Policy Attach Points 177
OSPFv3 Policy Attach Points 180
IS-IS Policy Attach Points 182
Nondestructive Editing of Routing Policy 183
Attached Policy Modification 183
Nonattached Policy Modification 183
Editing Routing Policy Configuration Elements 184
Hierarchical Policy Conditions 186
Apply Condition Policies 186
Nested Wildcard Apply Policy 189
VRF Import Policy Enhancement 189
Match Aggregated Route 190
Remove Private AS in Inbound Policy 190
Implementing Static Routes 191
CHAPTER 6
Restrictions for Implementing Static Routes 191
Configure Static Route 192
Floating Static Routes 193
Configure Floating Static Route 193
Configure Static Routes Between PE-CE Routers 195
IPv4 Multicast Static Routes 196
Configure Multicast Static Routes 197
Default VRF 198
Associate VRF with a Static Route 198
Configure Native UCMP for Static Routing 199
References for Static Routes 200
Static Route Functional Overview 201
Default Administrative Distance 201
Directly Connected Routes 201
Floating Static Routes 202
Fully Specified Static Routes 202
Recursive Static Routes 202
Implementing BFD 205
CHAPTER 7
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BFD Overview 205
Enabling BFD on a Static Route 206
Enabling BFD for OSPF on an Interface 207
Enable BFD for IS-IS on an Interface 208
Enabling BFD on a BGP Neighbor 209
Configure BFD Under a Dynamic Routing Protocol or Use a Static Route 210
Enable BFD for OSPF on an Interface 210
Enable BFD for OSPF3 on an Interface 211
Enable BFD over BGP 212
Enable BFD on an IPv4 Static Route 213
Clear and Display BFD Counters 213
BFD over Bundle 213
Enabling BFD Sessions on Bundle Members 214
Specifying the BFD Destination Address on a Bundle 214
Configuring the Minimum Thresholds for Maintaining an Active Bundle 215
Configuring BFD Packet Transmission Intervals and Failure Detection Times on a Bundle 216
BFD Transparency 217
Ethernet VPN Virtual Private Wire Service 218
Configuration 218
Running Configuration 219
Verification 220
Bidirectional Forwarding Detection over Logical Bundle 222
Configuration 222
Running Configuration 224
Verification 225
IPv4 Multihop BFD 227
Configure IPv4 Multihop BFD 227
Verification 228
Implementing UCMP 229
CHAPTER 8
ECMP vs. UCMP Load Balancing 230
UCMP Minimum Integer Ratio 230
Configuring IS-IS With Weight 231
Configuring IS-IS With Metric 232
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Configuring BGP With Weights 233
Configuring TE Tunnel With Weights 234
Policy-Based Tunnel Selection 235
Implementing Fast Reroute Loop-Free Alternate 249
CHAPTER 9
Prerequisites for Fast Reroute with Loop-Free Alternate 249
Restrictions for Fast Reroute with Loop-Free Alternate 249
IS-IS and FRR 250
Repair Paths 250
LFA Overview 250
LFA Calculation 251
Interaction Between RIB and Routing Protocols 251
Fast Reroute with Remote Loop-Free Alternate 252
Configuration 253
Running Configuration 254
Verification 255
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Contents