Vyatta NOS documentation

Learn how to install, configure, and operate Vyatta Network Operating System (Vyatta NOS), which helps to drive our virtual networking and physical platforms portfolio.

Advertising IPv6 and IPv4 prefixes over IPv4 and IPv6 eBGP peers

The BGP speaker can now carry multiple network layer protocols like IPv4 and IPv6. The following configuration examples show how to advertise an IPv6 prefix over an IPv4 connection and an IPv4 prefix over an IPv6 connection.

Advertising an IPv6 prefix over an IPv4 eBGP peer
Figure 1. Advertising an IPv6 prefix over an IPv4 eBGP peer

The following components of the topology are shown in the preceding figure.

  • R1 router with a router ID of 1.1.1.1 and R2 router with a router ID of 2.2.2.2 are two routers.
  • The IPv4 unicast address of R1 router is 198.51.100.2.
Table 1. Advertising an IPv6 prefix over an IPv4 eBGP peer
Router Step Commands
R1

Activate the neighbor for the IPv6 unicast address family to enable the exchange of IPv6 unicast routes.

vyatta@R1# set protocols bgp 100 address-family ipv6-unicast network 2001:db8::/64
R1

Set the network to advertise.

vyatta@R1# set protocols bgp 100 neighbor 198.51.100.2 address-family ipv4-unicast
vyatta@R1# set protocols bgp 100 neighbor 198.51.100.2 address-family ipv6-unicast
R1

Set R2 in the same AS as R1.

vyatta@R1# set protocols bgp 100 neighbor 198.51.100.2 remote-as 200 
R1

Show the advertised routes.

vyatta@R1:~$ show ip bgp neighbors 198.51.100.2 advertised-routes
BGP table version is 2, local router ID is 1.1.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete

IPv6 Unicast address family:
Network            Next Hop         Metric   LocPrf  Weight  Path
*> 2001:db8::/64   ::ffff:c633:6401                  32768    i

Total number of prefixes 1

From the preceding configuration example, you observe the following:

  • The 2001:db8::/64 prefix is configured with a network command.
  • The BGP IPv4 transport session with the IPv6 unicast address family is configured.
  • The 2001:db8::/64 prefix is advertised with the next hop that is assigned to the IPv4-mapped IPv6 address (::fffff:198.51.100.1) from router 1 to router 2.
Note: The forwarding next hop must be an active route. You must ensure that the forwarding next hop is an active route because the IPv4 mapped address and the IPv6-address is derived. Therefore Ciena recommends that you use a route map to set the IPv6 next hop (for example, 2001:cafe::1/64). When a route-map is used, prefix 2001:db8::/64 is advertised with nexthop 2001:cafe::1/64.
Advertising an IPv4 prefix over an IPv6 eBGP peer
Figure 2. Advertising an IPv4 prefix over an IPv6 eBGP peer

The following components of the topology are shown in the preceding figure.

  • R1 router with a router ID of 1.1.1.1 and R2 router with a router ID of 2.2.2.2 are two routers.
  • The IPv6 unicast address of R1 router is 203.0.113.0/24.
Table 2. Advertising an IPv4 prefix over an IPv6 eBGP peer
Router Step Command
R2

Activate the neighbor for the IPv6 unicast address family to enable the exchange of IPv6 unicast routes.

vyatta@R1# set protocols bgp 100 address-family ipv4-unicast network 203.0.113.0/24
R2

Set the network to advertise.

vyatta@R1# set protocols bgp 100 neighbor 2001:cafe::2 address-family ipv4-unicast
vyatta@R1# set protocols bgp 100 neighbor 2001:cafe::2 address-family ipv6-unicast
R2

Set R2 in the same AS as R1.

vyatta@R1# set protocols bgp 100 neighbor 2001:cafe::2 remote-as 200
R2

Show the advertised routes.

vyatta@R1:~$ show ip bgp neighbors 2001:cafe::2 advertised-routes
BGP table version is 1, local router ID is 1.1.1.1
Status codes: s suppressed, d damped, h history, valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete

IPv4 Unicast address family:
Network          Next Hop   Metric  LocPrf Weight Path
*> 203.0.113.0   1.1.1.1                   32768    i

Total number of prefixes 1

From the preceding configuration example, you observe the following:

  • The 203.0.113.0/24 prefix is configured with a network command.
  • The BGP IPv6 transport session with the IPv4 unicast address family is configured.
  • The 203.0.113.0/24 prefix is advertised with the next hop that is assigned to the router ID 1.1.1.1 from router 1 to router 2.
Note: Ciena recommends that you use a route map to set the IPv4 next hop (for example, 203.0.113.1). When a route map is used the 198.51.100.0/24 prefix is advertised with the 203.0.113.1 next hop.