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Compiled by alliedtelesis.com x Configuring IPv6 Routing Solutions using BGP4+

Compiled by alliedtelesis.com x Configuring IPv6 Routing Solutions using BGP4+ First Edition Compiled by: Jason Higgins and Sheldon Duthie About Allied Telesis, Inc. Founded in 1987, Allied Telesis is a world class leader in delivering IP/Ethernet network solutions to the global marketplace. We create innovative, standards-based IP networks that seamlessly connect users with their voice, video and data services. We are an international company headquartered in Japan with major divisions in Europe, Asia and North and South America. Our partners include the world’s largest distributors, integrators, solution providers and resellers to assure you receive immediate local service and support. Allied Telesis has been designing, manufacturing and selling networking products for over 20 years. Our philosophy of producing products of the highest quality, at affordable prices, has resulted in Allied Telesis products being deployed in networks of all types and sizes across the world. Our proven track record of providing solid technology, excellent support and full feature products has allowed Allied Telesis to become the worldwide de-facto standard in many areas of technology. With a portfolio of products that can provide end-to-end networking for both Service Provider, Enterprise and SMB customers, Allied Telesis is the natural choice for many world class organizations. Please visit us online at alliedtelesis.com Page ii Co-authors Jason Higgins Sheldon Duthie Technical Writer Carin van Bolderen Illustrator Angela Maxwell Editor Carin van Bolderen Review Team Andrew Riddell Sheldon Duthie Miranda de Gouw Cover Designer Angela Devonport Copyright © 2014 Allied T elesis Inc. All rights reserved. This documentation is subject to change without notice. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or any means electronic or mechanical, including photocopying and recording for any purpose other than the purchaser’s internal use without the written permission of Allied Telesis, Inc. Trademarks Allied Telesis, AlliedWare Plus, EPSRing, SwitchBlade, and VCStack are trademarks or registered trademarks in the United States and elsewhere of Allied Telesis, Inc. Adobe, Acrobat, and Reader are either registered trademarks or trademarks of Adobe Systems Incorporated in the United States and/or other countries. Additional brands, names, and products mentioned herein may be trademarks of their respective companies. Warning and Disclaimer The information in this guide is provided on an “as is” basis. The author and the publishers shall have neither liability nor responsibility to any person or entity with respect to any loss or damages arising from the information contained in this guide. Produced in New Zealand First Printing: March 2014 Document Number: C613-04008-00-REV A ISBN: 978-0-473-26986-9 Page iii About this Guide This guide briefly describes the Border Gateway Protocol 4+(BGP4+) in general terms and how to configure a variety of IPv6 routing scenarios using BGP4+ on AlliedWare Plus™. This guide is intended for audiences with a good understanding of network routing protocols and device configuration. The discussion begins with an overview of the BGP4+ protocol and related RFCs, how it operates, and where it is normally implemented. This is followed by a basic set-up guide which also outlines inter-operation with other vendors, basic and advanced set-up instructions for BGP peering, and how to verify BGP settings using appropriate AlliedWare Plus show commands. This section rounds off with a description of BGP and BGP4+ terms used throughout the guide. The guide then provides a variety of BGP4+ configuration scenarios. Each scenario includes a simple network diagram, step-by-step configuration instructions, and examples of command output verifying the configuration. The configuration examples are grouped into the following areas:  BGP4+ Basic setup page - 15  Redistribution page - 39  Route Filtering page - 53  Route Aggregation page - 99  Path Control page - 125  Load Sharing Examples page - 167  Session Management Options page - 189  Comparison of BGP Session Reset Methods page - 211 Which products, software version and license does it apply to? These configurations apply to AlliedWare Plus software version 5.4.3-2.5 and above, for the following Allied Telesis switches:  SwitchBlade x8100 Series  SwitchBlade x8100 Series with - CFC400, CFC960 controller and Premium license, AlliedWare Plus software version 5.4.4 only  SwitchBlade x908 extended mode, with Advanced L3 license  x610 Series switches with Advanced L3 license  x900 Series switches with Advanced L3 license This chapter covers the following topics: Page v Contents Configuring IPv6 Routing Solutions using BGP4+ ...................................................................................................i About this Guide...........................................................................................................................................................iii Chapter 1 |BGP Overview........................................................................................................................................ 1 BGP4+ operation............................................................................................................................................................................................1 BGP4+ show commands............................................................................................................................................................................3 BGP4+ implementation...............................................................................................................................................................................5 BGP and BGP4+ terminology..................................................................................................................................................................7 BGP path attributes........................................................................................................................................................................................9 The BGP best path algorithm and invalid paths.......................................................................................................................... 11 Chapter 2 |BGP4+ Basic Setup.............................................................................................................................. 15 BGP sessions between two devices................................................................................................................................................... 15 Peering methods ........................................................................................................................................................................................... 16 Disabling exchange of IPv4 prefixes over an IPv6 peering.................................................................................................... 18 Enabling IPv6 information exchange to an IPv6 peer............................................................................................................... 21 Establishing a BGP neighborship using the IPv6 link-local address................................................................................... 24 Establish a BGP neighborship using VLAN interfaces.............................................................................................................. 27 Setting up BGP neighbors using loopback interfaces as the update source............................................................... 30 Advanced setup options for BGP sessions.................................................................................................................................... 34 Verification of BGP settings..................................................................................................................................................................... 36 Chapter 3 |Redistribution ....................................................................................................................................... 39 Redistributing all known OSPFv3 routes into BGP................................................................................................................... 39 Redistributing selected OSPFv3 routes into BGP using a route map with the redistribution statement.. 42 Using a route map with BGP default-originate to advertise a default route conditionally ............................... 45 Using redistribution to dynamically advertise RIPng routes into BGP ........................................................................... 48 Using a route map to redistribute specific RIPng routes into BGP.................................................................................. 50 Chapter 4 |Route Filtering...................................................................................................................................... 53 Using regular expressions to filter prefixes based on AS path........................................................................................... 53 Using regular expression to deny prefixes originating from a specific AS in outgoing updates...................... 54 Using regular expression to only deny networks originating from a specific AS..................................................... 59 Using regular expression to only permit networks originating from a neighbor AS............................................. 62 Using regular expression to only permit networks originating from a specific AS................................................. 65 Using regular expression to only permit networks passing through a specific AS ................................................. 68 Using distribute lists to filter routing updates - Inbound method ................................................................................... 71 Using distribute lists to filter routing updates - Outbound method................................................................................ 75 Using BGP Outbound Route Filtering to dynamically filter outbound updates ....................................................... 78 Using Prefix lists to filter routing updates - Inbound method ........................................................................................... 84 Using Prefix lists to filter routing updates - Outbound method........................................................................................ 88 Using the BGP well-known community attribute (no-advertise) to perform route filtering............................ 92 Using the BGP well-known community attribute (no-export) to perform route filtering................................. 95 Page vi Chapter 5 |Route Aggregation............................................................................................................................... 99 BGP route aggregation rules...................................................................................................................................................................99 Setup basic route aggregation in BGP4+ without suppressing longer prefixes in routing updates............101 Setup basic route aggregation in BGP4+ and suppress more specific prefixes from being advertised...107 Setup basic route aggregation to aggregate routes received from a neighboring AS........................................112 Setup an unsuppress map to advertise longer prefixes suppressed by an aggregate address ......................119 Chapter 6 |Path Control....................................................................................................................................... 125 Using local preference to change the preferred path for selected prefix(es) - Inbound method...............125 Using local preference to change the preferred path for selected prefix(es) - Outbound method..........131 Multi-Exit Discriminator (MED).........................................................................................................................................................138 Using deterministic-med to ensure MED comparison from the same AS...............................................................141 Comparing MED from different AS to change the path preference............................................................................145 Using deterministic-med and always-compare-med together to change the path preference.....................150 Using the BGP backdoor feature to change path preference without altering the default BGP AD........155 Using weight to change path preference for all prefix(es) received into a router ...............................................162 Chapter 7 |Load Sharing Examples..................................................................................................................... 167 Load sharing to a single ISP from a single dual-homed router using the max-paths command...................167 Using the weight command to achieve load balancing ........................................................................................................170 Using BGP multi hop to achieve load sharing............................................................................................................................175 Using BGP communities to adjust Local Preference ............................................................................................................179 Chapter 8 |Session Management Options......................................................................................................... 189 Adjusting the minimum interval between BGP Update messages within an AS ..................................................189 Limiting the number of permitted prefixes advertised by a neighbor .......................................................................192 Setup dampening for a prefix using a route map....................................................................................................................194 Using a route map to apply different dampening policies to separate prefixes.....................................................198 Using BGP synchronization to avoid reachability issues in a transit AS......................................................................200 Permit routes that originate from a remote AS with the same ASN..........................................................................205 Chapter 9 |Comparison of BGP Session Reset Methods.............................................................................. 211 Hard resetting a BGP session..............................................................................................................................................................212 Soft resetting a BGP neighbor session - inbound....................................................................................................................217 Soft resetting a BGP neighbor session - outbound ................................................................................................................221 Performing a “soft” update when Route Refresh is not supported on a BGP4+ peer....................................223 Preventing termination of a BGP session when capability negotiation issues occur...........................................227 Example without “dont-capability-negotiate”............................................................................................................................232 Setup BGP graceful-restart capability for all BGP neighbors............................................................................................236 Using peer groups to simplify administration and conserve processing and memory ......................................245 Additional Information ............................................................................................................................................ 250 CHAPTER 1 | BGP4+ operation | Page 1 CHAPTER 1 BGP Overview Border Gateway Protocol (BGP for IPv4 and BGP4+ for IPv6) is an exterior gateway protocol (EGP). The purpose of BGP is to advertise, learn, and choose the best paths via the Internet. The BGP4 protocol, defined in RFC 4271, is an external routing protocol used to connect different Autonomous Systems (AS). The BGP4 protocol was updated by RFC 4760 which added support for uploads/s1/ compiled-by.pdf