allocate-label all

[Arjun Dabol]

hi experts, I have 2 doubts : plz help

1.what is the use of  "allocate-label all" : command ?

eg : address-family ipv6 unicast

        allocate-label all

2. under which scenario we use below config ? ipv4 address under ipv4 add family.

address-family ipv6

neighbor <IPV4 Address> activate

[Nagendra Kumar Nainar · Accepted solution]

Hi Arjun,

1.what is the use of  "allocate-label all" : command ?

<Nagendra>For 6PE scenarios (IPv6 over IPv4 LSP), border nodes needs to exchange a label for each IPv6 Prefix. "allocate-label all" is used to assign and advertise label for IPv6 prefixes.

2. under which scenario we use below config ? ipv4 address under ipv4 add family.

<Nagendra> BGP is multi protocol capable. In simple words, a single session between 2 neighbors is sufficient to advertise different address-families. For example, you can have a single IPv4 session over whcih you can advertise IPv4, VPNv4, IPv6, VPNv6, MVPN etc.

In your case, when you enable "neighbor <ipv4> activate" under IPv6 address-family, you are allowing the node to exchange IPv6 prefixes (redistributed into local BGP table) to this neighbor. You may hvae to tweak the nexthop to make it work.

-Nagendra

[Vinit Jain · Accepted solution]

1. This command is used to allocate labels by BGP. This is similar to having send-label command in Cisco IOS. This command is generally used in Inter-AS MPLS VPNs or when you want BGP to allocate labels rather than LDP

2. address-family ipv6 is used when you want to establish IPv6 neighborship and exchanging IPv6 routes

Regards

Vinit