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Make IPv4 and IPv6 BGP options syntax consistent
Closed, ResolvedPublicBUG


There is a long-established inconsistency in BGP options. Options for IPv4 are right inside the neighbor, while IPv6 options are inside "address-family ipv6-unicast". For example, we have "neighbor x.x.x.x route-map export Foo" for IPv4, but "neighbor x.x.x.x address-family ipv6-unicast route-map export Foo" for IPv6.

FRR migration uncovered a nasty shortcoming of this: its correct functioning was dependent on particular behaviour of the old Quagga that enabled IPv4 on all peers with IPv4 addresses, whether "no default ipv4 unicast" option was set or not. FRR exhibits logical behaviour and disabled IPv4 BGP on all peers if that option is enabled.

Making IPv4 and IPv6 syntax consistent will not only improve, well, syntax consistency, but also automatically resolve the issue with that behaviour change.


Difficulty level
Normal (likely a few hours)
Why the issue appeared?
Will be filled on close
Is it a breaking change?
Unspecified (possibly destroys the router)

Event Timeline

syncer changed the task status from Open to In progress.Sep 25 2018, 2:03 PM
syncer triaged this task as Normal priority.
syncer moved this task from Needs Triage to In Progress on the VyOS 1.2 Crux (VyOS 1.2.0-rc1) board.
syncer claimed this task.

@dmbaturin is there any reason the IPv6 peer-group is under address-family ipv6-unicast and the IPv4 peer-group is not? Seems this one was missed during migration?

neighbor 2001:DB8:FFFF::1 {
     address-family {
         ipv6-unicast {
             peer-group iBGP
neighbor {
     peer-group iBGP
c-po reopened this task as In progress.Jun 16 2019, 1:51 PM
c-po claimed this task.
c-po added a subscriber: syncer.
c-po removed c-po as the assignee of this task.Aug 17 2019, 12:43 AM
c-po set Is it a breaking change? to Unspecified (possibly destroys the router).