Border Gateway Protocol (BGP) IPv6 summarization is important an important aspect of managing routing in modern computer networks. As the internet continues to expand and evolve, individuals initiated the transition to IPv6 in order to manage and accommodate a larger mass of computer networks, which is the first and foremost priority.
BGP IPv6 summarization is an essential component of managing the routing tables to simplify and reduce the complexity of network infrastructure and facilitate a better exchange of routing information within different networks.
IPv6 routes can be aggregated or summarized in the same way as IPv4 routes; the format is the same, but the configuration is grouped under the IPv6 address family using the command aggregate-address prefix/prefix-length [summary-only] [as-set]. The “aggregate-address” command is used to create a summary route for a group of specific IPv6 routes. The “prefix/prefix-length” parameter specifies the network prefix and its length to be summarized.
The optional “summary-only” keyword ensures that only the summarized route is advertised, hiding the specific routes. Additionally, the “as-set” option allows the summary route to include multiple autonomous system numbers. This allows for a more efficient routing table and reduces the amount of information exchanged between routers.
BGP IPv6 Summarization Configuration
In this example, 2 routers, AS 65100 and AS 65200, are connected via their Gigabit Ethernet interfaces Gig0/0. Each router has a loopback interface and an IPv4 and IPv6 address assigned. See the topology below.
Router 1
Router1(config)#ipv6 unicast-routing Router1(config)#interface loopback 0 Router1(config-if)#ipv6 enable Router1(config-if)#ipv6 address 2001:DB8::1/128 Router1(config)#interface GigabitEthernet0/0 Router1(config-if)#ip address 192.168.10.1 255.255.255.0 Router1(config-if)#ipv6 enable Router1(config-if)#ipv6 address 2001:DB8:0:10::1/64 Router1(config)#router bgp 1 Router1(config-router)#neighbor 192.168.10.2 remote-as 65200 Router1(config-router)#bgp log-neighbor-changes Router1(config-router)#address-family ipv6 Router1(config-router-af)#network 2001:db8::1/128 Router1(config-router-af)#neighbor 192.168.10.2 activate Router1(config-router-af)#neighbor 192.168.10.2 route-map IPV6_NEXT_HOP in Router1(config-router-af)#route-map IPV6_NEXT_HOP permit 10 Router1(config-route-map)#set ipv6 next-hop 2001:DB8:0:10::2
Router 2
Router2(config)#ipv6 unicast-routing Router2(config)#interface loopback 0 Router2(config-if)#ipv6 enable Router2(config-if)#ipv6 address 2001:DB8::2/128 Router2(config)#interface GigabitEthernet0/0 Router2(config-if)#ip address 192.168.10.2 255.255.255.0 Router2(config-if)#ipv6 enable Router2(config-if)#ipv6 address 2001:DB8:0:10::2/64 Router2(config)#router bgp 2 Router2(config-router)#neighbor 192.168.10.1 remote-as 65100 Router2(config-router)#bgp log-neighbor-changes Router2(config-router)#address-family ipv6 Router2(config-router-af)#network 2001:db8::2/128 Router2(config-router-af)#neighbor 192.168.10.1 activate Router2(config-router-af)#neighbor 192.168.10.1 route-map IPV6_NEXT_HOP in Router2(config-router-af)#route-map IPV6_NEXT_HOP permit 10 Router2(config-route-map)#set ipv6 next-hop 2001:DB8:0:10::1
Verification
Router1#show ip bgp ipv6 unicast BGP table version is 2, local router ID is 192.168.10.1 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, x best-external, f RT-Filter Origin codes: i - IGP, e - EGP, ? - incomplete Network Next Hop Metric LocPrf Weight Path *> 2001:DB8::1/128 :: 0 32768 i * 2001:DB8::2/128 ::FFFF:192.168.10.2 0 0 2 i
Router1#show ip bgp ipv6 unicast | begin 2001 *> 2001:DB8::1/128 :: 0 32768 i *> 2001:DB8::2/128 2001:DB8:0:10::2
Router2#show ip bgp ipv6 unicast BGP table version is 2, local router ID is 192.168.10.2 Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, r RIB-failure, S Stale, m multipath, b backup-path, x best-external, f RT-Filter Origin codes: i - IGP, e - EGP, ? - incomplete Network Next Hop Metric LocPrf Weight Path * 2001:DB8::1/128 ::FFFF:192.168.10.1 0 0 1 i *> 2001:DB8::2/128 :: 0 32768 i
Router2#show ip bgp ipv6 unicast | begin 2001 *> 2001:DB8::1/128 2001:DB8:0:10::1
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