Cisco ASR 9000 Series User manual

Cisco ASR 9000 Series Aggregation Services Router MPLS
Configuration Guide, Release 4.3.x
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Text Part Number: OL-28381-02

©2014 Cisco Systems, Inc. All rights reserved.

CONTENTS
Preface Preface xv
Changes to This Document xv
Obtaining Documentation and Submitting a Service Request xv
CHAPTER 1 New and Changed Feature Information in Cisco IOS XR Release 4.3.x 1
New and Changed Feature Information in Cisco IOS XR Release 4.3.x 1
CHAPTER 2 Implementing MPLS Label Distribution Protocol 5
Prerequisites for Implementing Cisco MPLS LDP 6
Information About Implementing Cisco MPLS LDP 6
Overview of Label Distribution Protocol 6
Label Switched Paths 6
LDP Control Plane 6
Exchanging Label Bindings 8
LDP Forwarding 9
LDP Graceful Restart 10
Control Plane Failure 11
Phases in Graceful Restart 12
Recovery with Graceful-Restart 13
Label Advertisement Control (Outbound Filtering) 14
Label Acceptance Control (Inbound Filtering) 14
Local Label Allocation Control 15
Session Protection 15
IGP Synchronization 16
IGP Auto-configuration 17
LDP Nonstop Routing 17
IP LDP Fast Reroute Loop Free Alternate 18
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Downstream on Demand 19
Explicit-Null and Implicit-Null Labels 20
How to Implement MPLS LDP 20
Configuring LDP Discovery Parameters 21
Configuring LDP Discovery Over a Link 22
Configuring LDP Discovery for Active Targeted Hellos 24
Configuring LDP Discovery for Passive Targeted Hellos 26
Configuring Label Advertisement Control (Outbound Filtering) 27
Setting Up LDP Neighbors 29
Setting Up LDP Forwarding 31
Setting Up LDP NSF Using Graceful Restart 33
Configuring Label Acceptance Control (Inbound Filtering) 35
Configuring Local Label Allocation Control 37
Configuring Session Protection 38
Configuring LDP IGP Synchronization: OSPF 39
Configuring LDP IGP Synchronization: ISIS 40
Enabling LDP Auto-Configuration for a Specified OSPF Instance 42
Enabling LDP Auto-Configuration in an Area for a Specified OSPF Instance 44
Disabling LDP Auto-Configuration 45
Configuring LDP Nonstop Routing 47
Configuring LDP Downstream on Demand mode 48
Redistributing MPLS LDP Routes into BGP 49
Setting Up Implicit-Null-Override Label 51
Configuration Examples for Implementing MPLS LDP 52
Configuring LDP with Graceful Restart: Example 52
Configuring LDP Discovery: Example 52
Configuring LDP Link: Example 52
Configuring LDP Discovery for Targeted Hellos: Example 53
Configuring Label Advertisement (Outbound Filtering): Example 53
Configuring LDP Neighbors: Example 54
Configuring LDP Forwarding: Example 54
Configuring LDP Nonstop Forwarding with Graceful Restart: Example 54
Configuring Label Acceptance (Inbound Filtering): Example 55
Configuring Local Label Allocation Control: Example 55
Configuring LDP Session Protection: Example 55
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Configuring LDP IGP Synchronization—OSPF: Example 56
Configuring LDP IGP Synchronization—ISIS: Example 56
Configuring LDP Auto-Configuration: Example 56
Configure IP LDP Fast Reroute Loop Free Alternate: Examples 57
Verify IP LDP Fast Reroute Loop Free Alternate: Example 58
Additional References 61
CHAPTER 3 Implementing RSVP for MPLS-TE 63
Prerequisites for Implementing RSVP for MPLS-TE 64
Information About Implementing RSVP for MPLS-TE 64
Overview of RSVP for MPLS-TE 64
LSP Setup 65
High Availability 65
Graceful Restart 65
Graceful Restart: Standard and Interface-Based 66
Graceful Restart: Figure 67
ACL-based Prefix Filtering 68
RSVP MIB 68
Bandwidth Reservation Percentage 69
Information About Implementing RSVP Authentication 69
RSVP Authentication Functions 69
RSVP Authentication Design 69
Global, Interface, and Neighbor Authentication Modes 70
Security Association 71
Key-source Key-chain 72
Guidelines for Window-Size and Out-of-Sequence Messages 73
Caveats for Out-of-Sequence 73
How to Implement RSVP 74
Configuring Traffic Engineering Tunnel Bandwidth 74
Confirming DiffServ-TE Bandwidth 74
Enabling Graceful Restart 76
Configuring ACL-based Prefix Filtering 77
Configuring ACLs for Prefix Filtering 77
Configuring RSVP Packet Dropping 78
Verifying RSVP Configuration 80
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Enabling RSVP Traps 83
How to Implement RSVP Authentication 84
Configuring Global Configuration Mode RSVP Authentication 84
Enabling RSVP Authentication Using the Keychain in Global Configuration Mode 84
Configuring a Lifetime for RSVP Authentication in Global Configuration Mode 86
Configuring the Window Size for RSVP Authentication in Global Configuration
Mode 87
Configuring an Interface for RSVP Authentication 88
Specifying the RSVP Authentication Keychain in Interface Mode 88
Configuring a Lifetime for an Interface for RSVP Authentication 90
Configuring the Window Size for an Interface for RSVP Authentication 91
Configuring RSVP Neighbor Authentication 92
Specifying the Keychain for RSVP Neighbor Authentication 93
Configuring a Lifetime for RSVP Neighbor Authentication 94
Configuring the Window Size for RSVP Neighbor Authentication 95
Verifying the Details of the RSVP Authentication 97
Eliminating Security Associations for RSVP Authentication 97
Configuration Examples for RSVP 97
Bandwidth Configuration (Prestandard): Example 97
Bandwidth Configuration (MAM): Example 97
Bandwidth Configuration (RDM): Example 98
Refresh Reduction and Reliable Messaging Configuration: Examples 98
Refresh Interval and the Number of Refresh Messages Configuration: Example 98
Retransmit Time Used in Reliable Messaging Configuration: Example 99
Acknowledgement Times Configuration: Example 99
Summary Refresh Message Size Configuration: Example 99
Disable Refresh Reduction: Example 99
Configure Graceful Restart: Examples 99
Enable Graceful Restart: Example 100
Enable Interface-Based Graceful Restart: Example 100
Change the Restart-Time: Example 100
Change the Hello Interval: Example 100
Configure ACL-based Prefix Filtering: Example 100
Set DSCP for RSVP Packets: Example 101
Enable RSVP Traps: Example 101
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Configuration Examples for RSVP Authentication 101
RSVP Authentication Global Configuration Mode: Example 102
RSVP Authentication for an Interface: Example 102
RSVP Neighbor Authentication: Example 103
RSVP Authentication by Using All the Modes: Example 103
Additional References 104
CHAPTER 4 Implementing MPLS Forwarding 107
Prerequisites for Implementing Cisco MPLS Forwarding 107
Restrictions for Implementing Cisco MPLS Forwarding 108
Information About Implementing MPLS Forwarding 108
MPLS Forwarding Overview 108
Label Switching Functions 108
Distribution of Label Bindings 109
MFI Control-Plane Services 109
MFI Data-Plane Services 109
MPLS Maximum Transmission Unit 110
Label Security for BGP Inter-AS Option-B 110
How to Implement MPLS Forwarding 110
Configuring MPLS Label Security 110
Additional References 111
CHAPTER 5 Implementing MPLS Traffic Engineering 113
Prerequisites for Implementing Cisco MPLS Traffic Engineering 114
Restrictions for Implementing GMPLS UNI 115
Information About Implementing MPLS Traffic Engineering 115
Overview of MPLS Traffic Engineering 115
Benefits of MPLS Traffic Engineering 115
How MPLS-TE Works 116
MPLS Traffic Engineering 117
Backup AutoTunnels 117
AutoTunnel Attribute-set 118
Link Protection 118
Node Protection 118
Backup AutoTunnel Assignment 119
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Explicit Paths 120
Periodic Backup Promotion 120
Protocol-Based CLI 121
Differentiated Services Traffic Engineering 121
Prestandard DS-TE Mode 121
IETF DS-TE Mode 121
Bandwidth Constraint Models 122
Maximum Allocation Bandwidth Constraint Model 122
Russian Doll Bandwidth Constraint Model 122
TE Class Mapping 123
Flooding 123
Flooding Triggers 123
Flooding Thresholds 124
Fast Reroute 124
MPLS-TE and Fast Reroute over Link Bundles 125
Ignore Intermediate System-to-Intermediate System Overload Bit Setting in MPLS-TE 125
Flexible Name-based Tunnel Constraints 126
MPLS Traffic Engineering Interarea Tunneling 127
Interarea Support 127
Multiarea Support 128
Loose Hop Expansion 128
Loose Hop Reoptimization 129
ABR Node Protection 129
Fast Reroute Node Protection 129
MPLS-TE Forwarding Adjacency 129
MPLS-TE Forwarding Adjacency Benefits 130
MPLS-TE Forwarding Adjacency Restrictions 130
MPLS-TE Forwarding Adjacency Prerequisites 130
Path Computation Element 130
Policy-Based Tunnel Selection 132
Policy-Based Tunnel Selection 132
Policy-Based Tunnel Selection Functions 132
PBTS Forward Class 133
PBTS Restrictions 134
PBTS Default Class Enhancement 134
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Path Protection 135
Pre-requisites for Path Protection 135
Restrictions for Path Protection 136
Restrictions for Explicit Path Protection 137
Co-existence of Path Protection with Fast Reroute 137
MPLS-TE Automatic Bandwidth 137
MPLS-TE Automatic Bandwidth Overview 138
Adjustment Threshold 139
Overflow Detection 139
Restrictions for MPLS-TE Automatic Bandwidth 140
Point-to-Multipoint Traffic-Engineering 140
Point-to-Multipoint Traffic-Engineering Overview 140
Point-to-Multipoint RSVP-TE 142
Point-to-Multipoint Fast Reroute 142
Point-to-Multipoint Label Switch Path 143
Path Option for Point-to-Multipoint RSVP-TE 143
MPLS Traffic Engineering Shared Risk Link Groups 145
Explicit Path 145
Fast ReRoute with SRLG Constraints 146
Importance of Protection 148
Delivery of Packets During a Failure 149
Multiple Backup Tunnels Protecting the Same Interface 149
Weighted-SRLG Auto-backup Path Computation 149
SRLG Limitations 150
Soft-Preemption 150
Path Option Attributes 151
Configuration Hierarchy of Path Option Attributes 151
Traffic Engineering Bandwidth and Bandwidth Pools 152
Path Option Switchover 152
Path Option and Path Protection 153
Auto-Tunnel Mesh 153
Destination List (Prefix-List) 154
How to Implement Traffic Engineering 155
Building MPLS-TE Topology 155
Creating an MPLS-TE Tunnel 158
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Configuring Forwarding over the MPLS-TE Tunnel 160
Protecting MPLS Tunnels with Fast Reroute 162
Enabling an AutoTunnel Backup 167
Removing an AutoTunnel Backup 168
Establishing MPLS Backup AutoTunnels to Protect Fast Reroutable TE LSPs 169
Establishing Next-Hop Tunnels with Link Protection 171
Configuring a Prestandard DS-TE Tunnel 173
Configuring an IETF DS-TE Tunnel Using RDM 175
Configuring an IETF DS-TE Tunnel Using MAM 178
Configuring MPLS -TE and Fast-Reroute on OSPF 181
Configuring the Ignore Integrated IS-IS Overload Bit Setting in MPLS-TE 182
Configuring Flexible Name-based Tunnel Constraints 183
Assigning Color Names to Numeric Values 184
Associating Affinity-Names with TE Links 185
Associating Affinity Constraints for TE Tunnels 186
Configuring IS-IS to Flood MPLS-TE Link Information 188
Configuring an OSPF Area of MPLS-TE 189
Configuring Explicit Paths with ABRs Configured as Loose Addresses 191
Configuring MPLS-TE Forwarding Adjacency 192
Configuring a Path Computation Client and Element 193
Configuring a Path Computation Client 193
Configuring a Path Computation Element Address 195
Configuring PCE Parameters 196
Configuring Policy-based Tunnel Selection 198
Configuring Forwarding Path 200
Configuring Path Protection on MPLS-TE 201
Enabling Path Protection for an Interface 202
Assigning a Dynamic Path Option to a Tunnel 203
Forcing a Manual Switchover on a Path-Protected Tunnel 204
Configuring the Delay the Tunnel Takes Before Reoptimization 205
Configuring the Automatic Bandwidth 207
Configuring the Collection Frequency 207
Forcing the Current Application Period to Expire Immediately 208
Configuring the Automatic Bandwidth Functions 209
Configuring the Shared Risk Link Groups 212
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