BGP.is it mandatory to do clear ip bgp after adding new network

[webstd.design]

Hi,

<RouterID 10.10.10.1>----eBGP----<RouterID 10.10.1.1>---adding new subnet 10.10.1.2

In case if we add new subnet like 10.10.1.2 into bgp using network command should we do clear ip bgp x.x.x.x?

Thanks

[Thotsaphon Lueangwattanaphong]

Hi,

   No need. Just make sure that the new "network" you added is already in RIB.

HTH,

Toshi

[cadet alain]

Hi,

no it isn't and as a side note as most routers support route refresh you should be better doing a clear ip bgp x.x.x.x in or

clear ip bgp x.x.x.x out which are soft resets which don't tear the peering.

Regards.

Alain.

[webstd.design]

--10.10.10.2----eBGP----10.10.1.2-----adding new subnet 10.10.1.20/30

I'm not able to find subnetwork 10.10.1.20/30 with command below:

10.10.10.1> sh ip bgp neigh 10.10.1.2 routes

Also this command doesn't show route 10.10.1.20/30

10.10.1.1> sh ip bgp neigh 10.10.1.2 advertised-routes

Can see 10.10.1.20/30 in below

10.10.1.1>sh ip bgp

Can't see 10.10.1.20/30 in below

10.10.10.1>sh ip bgp

What should I within clear ip bgp? or any other usefull command? Any glue?

Thanks

[sfaizul]

clear ip bgp is not mandatory the only the important thing is the mask in the network statment and in the routing table should be same.

syed.

[milan.kulik]

Hi,

aren't you filtering the prefixes advertised to  10.10.1.2?

Outgoing route-map, filter-list, etc.?

You could try

clear ip bgp 10.10.1.2 soft

but it should not be necessary if the  10.10.1.20/30 was in the RIB at the moment you added

network 10.10.1.20 mask 255.255.255.252

to you BGP config.

Another low probability  chance:

Aren't you receiving the same prefix from 10.10.1.2 already with better BGP attributes?

In that way you would not advertise  the prefix back.

Or isn't the prefix next-hop pointing to 10.10.1.2?

HTH,

Milan

[webstd.design]

10.10.1.20 is directly connected network on RouterID 10.10.1.1

I don't think that I should add this route into IGP, as we use eBGP between RouterID 10.10.1.1 and RouterID 10.10.10.1

[webstd.design]

If we modify policy - should we do clear ip bgp soft?

[cadet alain · Accepted solution]

Hi,

if you modify a policy then you must do either a soft reset or a route-refresh( with clear ip bgp x.x.x.x in or clear ip bgp x.x.x.x out).

Regards.

Alain