Cisco NCS 5500 Series User manual

BGP Configuration Guide for Cisco NCS 5500 Series Routers, IOS XR
Release 6.2.x
First Published: 2017-07-14
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CONTENTS
Preface Preface ix
Changes to This Document ix
Obtaining Documentation and Submitting a Service Request ix
CHAPTER 1 New and Changed BGP Features 1
New and Changed BGP Features 1
CHAPTER 2 Implementing BGP 3
BGP Functional Overview 3
Enable BGP Routing 4
Adjust BGP Timers 7
Change BGP Default Local Preference Value 8
Configure MED Metric for BGP 9
Configure BGP Weights 10
Tune BGP Best-Path Calculation 11
Set BGP Administrative Distance 13
Indicate BGP Back-door Routes 14
Configure Aggregate Addresses 16
Autonomous System Number Formats in BGP 18
2-byte Autonomous System Number Format 18
4-byte Autonomous System Number Format 18
as-format Command 18
BGP Multi-Instance and Multi-AS 18
Configure Multiple BGP Instances for a Specific Autonomous System 19
BGP Routing Domain Confederation 20
Configure Routing Domain Confederation for BGP 20
BGP Additional Paths 23
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Configure BGP Additional Paths 23
BGP Maximum Prefix 25
Configure Discard Extra Paths 25
BGP Best-External Path 27
Configure Best-External Path Advertisement 28
BGP Local Label Retention 29
Retain Allocated Local Label for Primary Path 29
iBGP Multipath Load Sharing 30
Configure iBGP Multipath Load Sharing 30
Route Dampening 32
Configuring BGP Route Dampening 32
Routing Policy Enforcement 33
Apply Policy When Updating Routing Table 33
Configure BGP Neighbor Group and Neighbors 35
Disable BGP Neighbor 38
Resetting Neighbors Using BGP Inbound Soft Reset 39
Resetting Neighbors Using BGP Outbound Soft Reset 40
Reset Neighbors Using BGP Hard Reset 41
Configure Software to Store Updates from Neighbor 42
Log Neighbor Changes 43
BGP Route Reflectors 43
Configure Route Reflector for BGP 44
Configure BGP Route Filtering by Route Policy 46
Configure BGP Attribute Filtering 47
BGP Next Hop Tracking 49
Configure BGP Next-Hop Trigger Delay 49
Disable Next-Hop Processing on BGP Updates 50
BGP Cost Community 51
Configure BGP Cost Community 51
Configure BGP Community and Extended-Community Advertisements 54
Redistribute iBGP Routes into IGP 56
Redistribute IGPs to BGP 57
Update Groups 58
Monitor BGP Update Groups 59
L3VPN iBGP PE-CE 60
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Restrictions for L3VPN iBGP PE-CE 60
Configuring L3VPN iBGP PE-CE 60
Flow-tag propagation 63
Restrictions for flow-tag propagation 63
Source and destination-based flow tag 63
Configure Source and Destination-based Flow Tag 63
BGP Keychains 65
Configure Keychains for BGP 65
BGP Nonstop Routing 66
Configure BGP Nonstop Routing 66
Disable BGP Nonstop Routing 66
Re-enable BGP Nonstop Routing 67
Accumulated Interior Gateway Protocol Attribute 68
Originate Prefixes with AiGP 68
Configure BGP Accept Own 70
BGP Link-State 73
Configure BGP Link-state 74
Configure Domain Distinguisher 75
BGP Permanent Network 75
Configure BGP Permanent Network 76
Advertise Permanent Network 78
Enable BGP Unequal Cost Recursive Load Balancing 80
DMZ Link Bandwidth for Unequal Cost Recursive Load Balancing 83
Enable BGP Unequal Cost Recursive Load Balancing 84
DMZ Link Bandwidth Over EBGP Peer 87
Sending and Receiving DMZ Link Bandwidth Extended Community over eBGP
Peer 88
BGP Prefix Origin Validation Based on RPKI 90
Configure RPKI Cache-server 90
Configure RPKI Prefix Validation 93
Configure RPKI Bestpath Computation 95
Resilient Per-CE Label Allocation Mode 96
Configure Resilient Per-CE Label Allocation Mode Under VRF Address Family 96
Configure Resilient Per-CE Label Allocation Mode Using Route-Policy 98
BGP VRF Dynamic Route Leaking 100
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Configure VRF Dynamic Route Leaking 100
Configuring a VPN Routing and Forwarding Instance in BGP 102
Define Virtual Routing and Forwarding Tables in Provider Edge Routers 102
Configure Route Distinguisher 104
Configure PE-PE or PE-RR Interior BGP Sessions 106
Configure BGP as PE-CE Protocol 109
Resetting an eBGP Session Immediately Upon Link Failure 113
Selective FIB Download 114
Configuring Selective FIB Download 116
Information about Implementing BGP 117
BGP Router Identifier 118
BGP Default Limits 118
BGP Attributes and Operators 119
BGP Best Path Algorithm 130
Comparing Pairs of Paths 130
Order of Comparisons 132
Best Path Change Suppression 133
BGP Update Generation and Update Groups 133
BGP Update Group 134
BGP Cost Community Reference 134
BGP Next Hop Reference 134
BGP Nonstop Routing Reference 136
BGP Route Reflectors Reference 138
iBGP Multipath Load Sharing Reference 141
L3VPN iBGP PE-CE Reference 142
MPLS VPN Carrier Supporting Carrier 142
Per VRF and Per CE Label for IPv6 Provider Edge 143
IPv6 Unicast Routing 143
Remove and Replace Private AS Numbers from AS Path in BGP 144
BGP Update Message Error Handling 144
BGP Error Handling and Attribute Filtering Syslog Messages 145
BGP-RIB Feedback Mechanism for Update Generation 145
Use-defined Martian Check 146
CHAPTER 3 EVPN Virtual Private Wire Service (VPWS) 147
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Information About EVPN-VPWS Single Homed 147
Configuring L2VPN EVPN Address Family Under BGP 148
Configuring EVPN-VPWS 149
Configuring EVPN-VPWS: Example 151
CHAPTER 4 BGP-based VPWS Autodiscovery 153
Configuring VPWS with BGP Autodiscovery and Signaling 153
VPWS with BGP Autodiscovery and BGP Signaling 156
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Preface
The Routing Configuration Guide for Cisco NCS 5500 Series Routers preface contains these sections:
•Changes to This Document, page ix
•Obtaining Documentation and Submitting a Service Request, page ix
Changes to This Document
This table lists the technical changes made to this document since it was first released.
Table 1: Changes to This Document
SummaryDate
Initial release of this document.March 2017
Republished for Release 6.2.2July 2017
Obtaining Documentation and Submitting a Service Request
For information on obtaining documentation, using the Cisco Bug Search Tool (BST), submitting a service
request, and gathering additional information, see What's New in Cisco Product Documentation.
To receive new and revised Cisco technical content directly to your desktop, you can subscribe to the What's
New in Cisco Product Documentation RSS feed. RSS feeds are a free service.
BGP Configuration Guide for Cisco NCS 5500 Series Routers, IOS XR Release 6.2.x
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BGP Configuration Guide for Cisco NCS 5500 Series Routers, IOS XR Release 6.2.x
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Preface
Obtaining Documentation and Submitting a Service Request