BGP soft-reconfiguration

[rpidcock@bankrcb.net]

Are there any negative impacts to implementing soft-reconfiguration as a normal standard.  I know that soft-reconfiguration needs to be enabled if I want to see received routes from a neighbor (i.e. show ip bgp neighbors x.x.x.x received-routes).

Are  there any negative impacts to implementing soft-reconfiguration on neighbors as a normal standard?

Thanks

Richard

[Deepak Kumar]

Hi,

As I know ther is no such impact but it needs some extra resources on the router as memory.

[Joseph W. Doherty]

As noted by Deepak, it uses memory, but later BGP supports route refresh. I.e. later BGP doesn't need to use that option.

[paul driver · Accepted solution]

Hello

 If have to append you bgp inbound policy the rtr will need to process it so with soft inbound configuration enabled the rtr will store a copy of advertised unfiltered routes locally so it can run run it’s inbound route policy against it locally before any routes are actually placed in the route table.

So I would say yes it can be very resource intensive if the rtrs are receiving large amounts of prefixes and even more so if they have multiple neighbours

If the rtrs and it’s peers support it then the route -refresh capability is a much much viable option as it allows the rtrs to perform a bgp soft reset which sends any new inbound route policy towards the bgp peers asking them to resend their advertised routes again without having your rtrs to store an unedited copy of the its received routes locally and running this same function locally thus saving valuable rtr resources on the rtrs.

[rpidcock@bankrcb.net]

Some of the routers in my environment but not all currently have the soft-reconfiguration enabled.  After reading your explanation and some other online research I see where, yes this will be at least somewhat more intensive on my routers.  My routers do support route refresh so I'm probably going to just leave it alone.

Thanks,