RE: bgp soft-reconfig in? posted 10/23/2002
Route Refresh Capability for BGP-4
Brian Dennis, CCIE #2210 (R&S/ISP Dial)
From: nobody@xxxxxxxxxxxxxx [mailto:nobody@xxxxxxxxxxxxxx] On Behalf Of
Sent: Wednesday, October 23, 2002 12:52 PM
To: Brian McGahan
Cc: Liban.Mohamed@xxxxxxxxxxxxxxx; ccielab@xxxxxxxxxxxxxx;
Subject: Re: bgp soft-reconfig in?
I take it the route-refresh is the new, (12.1) dynamic inbound soft
reset which requires no new config. (I was checking out the URL you
provided:) So I set up a very basic BGP connection to see if this was
negociated, both routers are running 12.2xx but I'm not sure what this
output is saying and can't find it on CCO:
C7206VXRB#sh ip bgp nei
BGP neighbor is 172.28.64.11, remote AS 10, external link
BGP version 4, remote router ID 172.28.64.11
BGP state = Established, up for 00:00:13
Last read 00:00:12, hold time is 180, keepalive interval is 60 seconds
Route refresh: advertised and received(old & new)
What is the "Route refresh: advertised and received(old & new)"? I
assume the routers have negociated that they are capable of dynamic
reset, what is the old and new??
Brian McGahan wrote:
> Soft-reconfig and route-refresh are two different
> They both accomplish pretty much the same thing, however they are
> implemented differently.
> Route-refresh is preferable over soft-reconfig, since there is
> no additional configuration required, and it does not require any
> additional memory resources. Soft-reconfig inbound can be dangerous
> use on a production BGP router, since inbound updates must be first
> cached, attributes applied, then flushed from memory. This means that
> if your router is short on memory, it could crash.
> For those of you with access to the Partner E-Learning
> connection, check out this link on multiprotocol extensions for BGP.
> gives a good overview of route-refresh and ORF.
> Brian McGahan, CCIE #8593
> Director of Design and Implementation
> CyscoExpert Corporation
> Internetwork Consulting & Training
> Voice: 847.674.3392
> Fax: 847.674.2625
> > -----Original Message-----
> > From: nobody@xxxxxxxxxxxxxx [mailto:nobody@xxxxxxxxxxxxxx] On Behalf
> > Liban.Mohamed@xxxxxxxxxxxxxxx
> > Sent: Sunday, October 20, 2002 2:47 PM
> > To: ccielab@xxxxxxxxxxxxxx; rich@xxxxxxxxxxxxxx
> > Subject: RE: bgp soft-reconfig in?
> > The dynamic inbound soft reset capability was added to
> > Cisco's BGP support in Cisco IOS Software Release
> > 12.0(6)T. BGP Soft Reset Enhancement is supported on
> > most Cisco router platforms up through the Cisco 7500
> > Series routers. Soft resets can be initiated without extra
> > commands using only the clear ip bgp in command.
> > Basically soft reconfiguration is to gracefully allow policies to be
> > configured and activated without "hardsetting" the bgp session.
> > are
> > two kinds. Outbound and inbound. For inbound, all recieved routes
> > stored
> > regardless of the fact whether they are accepted or denied. When we
> > clear
> > bgp with soft in, the polices are applied on the stored received
> > When we do clear bgp soft out, all entries in bgp table are re-run
> > new
> > updates are generated to be sent out.
> > syntax:
> > 1. sh ip bgp neighbor <peer address> received-routes
> > This displays all the received updates from neighbor
> > 2. neighbor <address> soft-reconfiguration <in>
> > This will start storing the received updates. So required for
> > soft
> > reconfig. Outbound reconfig does not need anything to be configured.
> > Thanks,
> > Liban Mohamed
> > IP Engineer
> > Sprintlink Internet BackBone
> > www.sprint.net
> > -----Original Message-----
> > From: rich [mailto:rich@xxxxxxxxxxxxxx]
> > Sent: Sunday, October 20, 2002 2:56 PM
> > To: ccielab
> > Cc: rich
> > Subject: bgp soft-reconfig in?
> > Is it true, when the neighbors support;
> > Neighbor capabilities: (taken from sho ip bgp neighbor)
> > Route refresh: advertised and received
> > Address family IPv4 Unicast: advertised and received
> > that you don't need to use the neighbor x.x.x.x soft-reconfiguration
> > inbound command? I have not used this command once. After making a
> > change to my bgp I just do a clear ip bgp XX sof.
> > Rich
Sr. Network Engineer
"You don't make the poor richer by making the rich poorer." --Winston