address-family ipv4 unicast + nexus 7k

[kmothukuri]

Hi All ,

What is the purpose of address-family ipv4 under BGP and also under neighbor on nexus 7k.

If You i remove address-family ipv4 from bgp then what kind of impact would be there .

example nexus 7k switch

router bgp 10

router-id x.x.x.x

address-family ipv4 unicast   --- If i remove this command then what would be the impact .

network x.x.x.x

network y.y.y.y

neighbor a.a.a.a remote-as 11

address-family ipv4 unicast

[pieterh]

explained in this post

Now, the address-family ipv4 declares neighbors with whom we want to exchange normal IPv4 unicast routes. This may be surprising because to exchange IPv4 routes with a neighbor, it is sufficient to simply define that neighbor by its address. The fact is that for backward compatibility with older BGP versions that have not been multiprotocol-capable, the BGP implicitly assigns all defined neighbors to an invisible address-family ipv4 section. In other words, as soon as you define a neighbor, it is automatically being added to an invisible address-family ipv4 section so that you don't have to do it manually.

[kmothukuri]

Thank you Pieterh for the reply and info.

Yes you are correct , traditional  cisco router and L3 switches have address-family ipv4 unicast as invincible .But on nexus 7ks we have to enter into address-family ipv4 unicast prior configuring network / neighbor statements.

My question is , if we remove address-family ipv4 unicast command from BGP on nexus 7k , what would happen to BGP routes and states ?

Router bgp 10

no address-family ipv4 unicast   - If I remove it from nexus 7k switch what would be the impact to bgp routes /states

network 10.x.x.x /24

network 20.x.x.x/24

neighbor x.x.x.x remote-as 11

address-family ipv4 unicast

[Giuseppe Larosa]

Hello @kmothukuri ,

if NX-OS is more similar to IOS XR that is strictly hierarchical, the impact would be huge and you would torn down the BGP sessions when removing address-family ipv4 unicast or the parser will prompt you that there are established peers.

I would suggest to avoid any change for safety. The configuration is easily readable with address-family ipv4 unicast.

Hope to help

Giuseppe