Clearing of the BGP Process

[martyyy]

Hi, 

Whenever we edit the prefix-list or route-map associated to a specific BGP/OSPF neighbor, we have to clear the BGP/OPSF process to see the effects of the newly made changes. This adds an additional overhead every time we make changes.

We would like to understand if this is some kind of fail-safe mechanism or is there anything which we are missing in our configuration.

TIA :) 

[dingjerry_FTNT]

Hi @martyyy ,

I think that you need to soft reset BGP sessions at least:

https://community.fortinet.com/t5/FortiGate/Technical-Tip-BGP-soft-reset-to-refresh-BGP-routing-tabl...

[Toshi_Esumi]

Filtering (prefix-list, route-map, etc.) changes won't change its routes (BGP) or LSAs (OSPF). Therefore it wouldn't trigger route/LSA updates to neighbors. You have to "soft" clear neighbor, as, etc. for BGP (uni-cast) or clear process for OSPF (multi-cast) to trigger advertisement or renegotiation of neighboring to re-filter routes/LSAs by the new filters you just set up.
Unlike OSPF, which does periodic reflooding of LSAs every 30 min, BGP doesn't re-advertise routes without any route changes. 

Toshi

[Tauri]

Hi, @martyyy!.
It is possible if you use soft reset BGP session:

execute router clear bgp <in|out> <neighbor-IP> soft

Also you could try to use a soft-reconfiguration if supported to re-apply the updated route-map.

config router bgp
    config neighbor
        edit x.x.x.x
            set soft-reconfiguration enable
        next
    end
end