© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v IPv6-Enabled Routing Protocols Understanding Multi-Protocol BGP (BGP4+)

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v2.04-2© 2006 Cisco Systems, Inc. All rights reserved. BGP4+ Multiprotocol extensions for BGP4: Enables other protocols besides IPv4 New identifier for the address family IPv6-specific extensions: Scoped addresses: NEXT_HOP contains a global IPv6 address and potentially a link-local address (only when there is link-local reachability with the peer). NEXT_HOP and NLRI are expressed as IPv6 addresses and prefixes in the multiprotocol attributes.

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v2.04-3© 2006 Cisco Systems, Inc. All rights reserved. 2001:db8:c18:2:1::F2001:db8:c18:2:1::1 Router1# interface Ethernet0 ipv6 address 2001:DB8:C18:2:1::F/64 router bgp no bgp default ipv4-unicast bgp router-id neighbor 2001:DB8:C18:2:1::1 remote-as address-family ipv6 neighbor 2001:DB8:C18:2:1::1 activate neighbor 2001:DB8:C18:2:1::1 prefix-list peer65002 in neighbor 2001:DB8:C18:2:1::1 prefix-list peer65002 out exit-address-family Cisco IOS BGP4+ Configuration Example Router1 Autonomous System Router2 Autonomous System 65002

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v2.04-4© 2006 Cisco Systems, Inc. All rights reserved. neighbor update-source router(config-router)# Identifies interface using update-source command set ipv6 next-hop router(config-route-map)# Applies a route map to set the global address in the NEXT_HOP attribute Link-local IPv6 address can be used instead of the site-local or global address. The following must be configured: Cisco IOS Link-Local BGP Peering Commands

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v2.04-5© 2006 Cisco Systems, Inc. All rights reserved. fe80::4fe80::1 E0 Router1# interface Loopback0 ipv6 address 2001:DB8:FFFF::F/64 interface Ethernet0 ipv6 address fe80::4 link-local router bgp no bgp default ipv4-unicast bgp router-id neighbor fe80::1 remote-as neighbor fe80::1 update-source Ethernet0 address-family ipv6 neighbor fe80::1 activate neighbor fe80::1 route-map nh6 out exit-address-family route-map nh6 set ipv6 next-hop 2001:db8:ffff::f Cisco IOS Link-Local BGP Peering Configuration Example Router1 Autonomous System Autonomous System Router2

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v2.04-6© 2006 Cisco Systems, Inc. All rights reserved. BGP Network Example 2001:db8:c18:2:1::f eBGP Tasks: Configure BGP to accept legal IPv6 prefixes only (prefix list). Prefer routes from Autonomous System (local preference). 2001:d00::/24 Autonomous System :db8:c18:2:1::2 2001:db8:c18:2:1::1 Autonomous System IPv6 Backbone Autonomous System 65003

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v2.04-7© 2006 Cisco Systems, Inc. All rights reserved. Filtering BGP routing updates 2001:DB8:2:1::/ :DB8:0001::/ :D00::/ :db8:c18:2:1::F Router1# router bgp no bgp default ipv4-unicast bgp router-id neighbor 2001:DB8:C18:2:1::1 remote-as address-family ipv6 neighbor 2001:DB8:C18:2:1::1 activate neighbor 2001:DB8:C18:2:1::1 prefix-list peer65002 in neighbor 2001:DB8:C18:2:1::1 prefix-list peer65002 out network 2001:D00::/24 exit-address-family ipv6 prefix-list peer65002 seq 5 permit 2001::/16 le :db8::/24 Cisco IOS BGP4+ Prefix Filtering Configuration Example Router1 2001:db8:c18:2:1::1 Router1

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v2.04-8© 2006 Cisco Systems, Inc. All rights reserved. Configure BGP to accept specific prefixes only (prefix list). router bgp no bgp default ipv4-unicast bgp router-id neighbor 2001:DB8:C18:2:1::1 remote-as neighbor 2001:DB8:C18:2:1::2 remote-as address-family ipv6 neighbor 2001:DB8:C18:2:1::1 activate neighbor 2001:DB8:C18:2:1::2 activate neighbor 2001:DB8:C18:2:1::1 prefix-list Legal in neighbor 2001:DB8:C18:2:1::2 prefix-list Legal in network 2001:D00::/24 exit-address-family ipv6 prefix-list CommonPref seq 20 permit 2001::/16 le 32 ipv6 prefix-list CommonPref seq 30 permit 2002::/16 Cisco IOS BGP4+ Prefix Filtering Configuration Example 2001:db8:c18:2:1::f Autonomous System :db8:c18:2:1::2 2001:db8:c18:2:1::1 Autonomous System Autonomous System 65003

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v2.04-9© 2006 Cisco Systems, Inc. All rights reserved. router bgp no bgp default ipv4-unicast neighbor 2001:DB8:C18:2:1::1 remote-as neighbor 2001:DB8:C18:2:1::2 remote-as address-family ipv6 neighbor 2001:DB8:C18:2:1::1 activate neighbor 2001:DB8:C18:2:1::2 activate neighbor 2001:DB8:C18:2:1::1 prefix-list CommonPref in neighbor 2001:DB8:C18:2:1::1 route-map From_65002 in neighbor 2001:DB8:C18:2:1::2 prefix-list CommonPref in network 2001:D00::/24 exit-address-family route-map From_65002 permit 10 set local-preference 120 Preferred routes from Autonomous System (local preference) Cisco IOS BGP Preferred Routes Configuration Example 2001:db8:c18:2:1::f Autonomous System :db8:c18:2:1::2 2001:db8:c18:2:1::1 Autonomous System Autonomous System 65003

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v © 2006 Cisco Systems, Inc. All rights reserved. show bgp ipv6 summary router(config)# Router1# show bgp summary BGP router identifier , local AS number BGP table version is 69046, main routing table version network entries and 92 paths using bytes of memory 826 BGP path attribute entries using bytes of memory 703 BGP AS-PATH entries using bytes of memory 0 BGP route-map cache entries using 0 bytes of memory 745 BGP filter-list cache entries using 8940 bytes of memory BGP activity 22978/18661 prefixes, 27166/22626 paths, scan interval 15 secs Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd 2001:DB8:C18:2:1:: d08h 92 Displays summary information regarding the state of the BGP neighbors Neighbor Information Resource Utilization by the BGP Process Cisco IOS BGP show Command

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v © 2006 Cisco Systems, Inc. All rights reserved. Summary BGP supports multiple network protocols, including IPv6, through the use of BGP multiprotocol extensions. BGP4+ supports IPv6 through the NEXT_HOP and NLRI attributes, which have been updated to support 128-bit values. BGP4+ supports IPv6 configuration through the address-family ipv6 configuration mode.

© 2006 Cisco Systems, Inc. All rights reserved.IP6FD v © 2006 Cisco Systems, Inc. All rights reserved.