From: Brian McGahan (bmcgahan@internetworkexpert.com)
Date: Mon Nov 24 2003 - 17:51:49 GMT-3
Jim,
It appears that adding soft-reconfig forces a hard reset, but
removing it does not:
R1(config)#router bgp 100
R1(config-router)#nei 204.12.1.254 remote-as 54
*Mar 4 20:15:07.836: %BGP-5-ADJCHANGE: neighbor 204.12.1.254 Up
R1(config-router)#nei 204.12.1.254 soft-reconfig in
*Mar 4 20:15:24.540: %BGP-5-ADJCHANGE: neighbor 204.12.1.254 Down Soft
reconfig change
*Mar 4 20:16:02.326: %BGP-5-ADJCHANGE: neighbor 204.12.1.254 Up
R1(config-router)#do sh ip bgp nei 204.12.1.254 received-routes
<snip>
Total number of prefixes 10
R1(config-router)#no nei 204.12.1.254 soft-reconfig in
R1(config-router)#do sh ip bgp nei 204.12.1.254 received-routes
% Inbound soft reconfiguration not enabled on 204.12.1.254
It must need a hard clear to populate the 'received' routes in
the first place. I'd be interested to see your results of the memory
savings if any.
Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987
Direct: 708-362-1418 (Outside the US and Canada)
> -----Original Message-----
> From: Jim Devane [mailto:jim@powerpulse.cc]
> Sent: Monday, November 24, 2003 1:49 PM
> To: 'Brian McGahan'
> Subject: RE: BGP Soft Reset (BGP RIB)
>
>
> Brian,
>
> Actually, I don't believe the hard reset takes place
> automatically. At least not on a 12012 running 12.0.25T
>
> I went through my config's and found 2 neighbors that had the
> soft-reconfig in place and after I checked to see that the
> opposite site router was running 12.2 I removed it.. the BGP
> session has not had any change to it.
>
> Unless you meant something else and I am mis-understanding.
>
> I hope I can schedule a window this week to reset the session
> to see if there is any memory savings.
>
> Thanks,
> Jim
>
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On
> Behalf Of Brian McGahan
> Sent: Monday, November 24, 2003 11:38 AM
> To: 'kurt'; ccielab@groupstudy.com
> Subject: RE: BGP Soft Reset (BGP RIB)
>
> Kurt,
>
> Correct, if route-refresh is supported you can 'clear
> ip bgp x.x.x.x in' without memory implications.
> Route-refresh is supported by default as of 12.0T.
>
> > also memory held by a previous soft (configured) reset will
> > be held until a reboot ??
>
> This I'm not sure about, but I'm going to guess no. If
> you add or remove the 'soft-reconfiguration inbound'
> statement a hard clear of the BGP neighbor automatically
> takes place. Therefore any cached received routes will be
> automatically flushed.
>
>
> HTH,
>
> Brian McGahan, CCIE #8593
> bmcgahan@internetworkexpert.com
>
> Internetwork Expert, Inc.
> http://www.InternetworkExpert.com
> Toll Free: 877-224-8987
> Direct: 708-362-1418 (Outside the US and Canada)
>
>
>
> > -----Original Message-----
> > From: kurt [mailto:kurt@cybernex.net]
> > Sent: Monday, November 24, 2003 1:18 PM
> > To: Brian McGahan
> > Subject: Re: BGP Soft Reset (BGP RIB)
> >
> >
> >
> > ok ,
> >
> > if i understand this correctly
> > i had been in the practice of setting
> > neighbor xxxxx soft-reconfiguration inbound
> > this causes the memory doubling issue
> > correct?
> >
> > if i do a
> > sh ip bgp neighbor
> > and it says route refresh is supported then i can
> > do a clear ip bgp * soft without memory implications
> > right ??
> >
> > also memory held by a previous soft (configured) reset will
> > be held until a reboot ??
> >
> > main-gw#sbn
> > BGP neighbor is , remote, external link
> > BGP version 4, remote router ID BGP state = Established,
> > up for 7w4d
> > Last read 00:00:00, hold time is 180, keepalive interval is
> > 60 seconds
> > Neighbor capabilities:
> > Route refresh: advertised and received(old & new)
> > Address family IPv4 Unicast: advertised and received
> > Message statistics:
> > InQ depth is 7
> > OutQ depth is 0
> > Sent Rcvd
> > Opens: 2 2
> > Notifications: 1 0
> > Updates: 6 3448866
> > Keepalives: 148547 148540
> > Route Refresh: 1 0
> > Total: 148557 3597408
> > Default minimum time between advertisement runs is 30 seconds
> >
> > For address family: IPv4 Unicast
> > BGP table version 10566014, neighbor version 0
> > Index 1, Offset 0, Mask 0x2
> > Inbound path policy configured
> > Outgoing update prefix filter list is locally-originated
> >
> >
> > ----- Original Message -----
> > From: "Brian McGahan" <bmcgahan@internetworkexpert.com>
> > To: "'Kurt Kruegel'" <kurt@cybernex.net>;
> > <Ken.Farrington@barclayscapital.com>; <ccielab@groupstudy.com>
> > Sent: Monday, November 24, 2003 1:50 PM
> > Subject: RE: BGP Soft Reset (BGP RIB)
> >
> >
> > > Kurt,
> > >
> > > If route-refresh is supported then both 'clear ip bgp * in'
> > and 'clear
> > > ip bgp * soft in' will do route-refresh. If route-refresh is not
> > > supported and soft-reconfiguration is not configured you
> > will get the
> > > following error message:
> > >
> > > router#clear ip bgp 172.16.4.3 in
> > > %BGP: Inbound soft reconfig for 172.16.4.3 not possible as it
> > > has neither refresh capability, nor inbound soft reconfig
> > >
> > > router#clear ip bgp 172.16.4.3 soft in
> > > %BGP: Inbound soft reconfig for 172.16.4.3 not possible as it
> > > has neither refresh capability, nor inbound soft reconfig
> > >
> > >
> > >
> > > HTH,
> > >
> > > Brian McGahan, CCIE #8593
> > > bmcgahan@internetworkexpert.com
> > >
> > > Internetwork Expert, Inc.
> > > http://www.InternetworkExpert.com
> > > Toll Free: 877-224-8987
> > > Direct: 708-362-1418 (Outside the US and Canada)
> > >
> > >
> > >
> > > > -----Original Message-----
> > > > From: Kurt Kruegel [mailto:kurt@cybernex.net]
> > > > Sent: Sunday, November 23, 2003 7:45 PM
> > > > To: Brian McGahan; Ken.Farrington@barclayscapital.com;
> > > > ccielab@groupstudy.com
> > > > Subject: Re: BGP Soft Reset (BGP RIB)
> > > >
> > > >
> > > > so ....
> > > > will
> > > > clear ip bgp in
> > > > force a route refresh ???
> > > >
> > > >
> > > >
> > > > ----- Original Message -----
> > > > From: "Brian McGahan" <bmcgahan@internetworkexpert.com>
> > > > To: <Ken.Farrington@barclayscapital.com>;
> <ccielab@groupstudy.com>
> > > > Sent: Sunday, November 23, 2003 8:21 PM
> > > > Subject: RE: BGP Soft Reset (BGP RIB)
> > > >
> > > >
> > > > > Ken,
> > > > >
> > > > > "Soft-reconfiguration" is Cisco's old proprietary way
> > of allowing
> > > > > changes in the BGP policy without tearing down the TCP
> > session and
> > > > > rebuilding it. "Route-refresh" is the standard and
> > > > preferred method
> > > > > to do so.
> > > > >
> > > > > Soft-reconfiguration must be preconfigured with the
> > > > 'neighbor x.x.x.x
> > > > > soft-reconfiguration inbound' bgp subcommand. With
> > > > soft-reconfig, the
> > > > > router caches prefixes received from a neighbor, then
> > installs a
> > > > > separate copy which is a result of configured inbound filters.
> > > > > The original copy can be seen by issuing the 'show ip bgp nei
> > > > > x.x.x.x received-routes' command. Using this method is not
> > > > > recommended, because the memory required on a per
> > neighbor basis
> > > > > can be
> > > > effectively
> > > > > doubled.
> > > > >
> > > > > Unlike soft-reconfig, route-refresh does not need to keep
> > > > two copies
> > > > > of the BGP table. There is no way to see the
> > unmodified received
> > > > > table other than going to the upstream side and doing a 'sh
> > > > ip bgp nei
> > > > > x.x.x.x advertised'. Route-refresh is part of the BGP
> > > > > capabilities exchange, and does not require any additional
> > > > > configuration.
> > > > >
> > > > >
> > > > > HTH,
> > > > >
> > > > > Brian McGahan, CCIE #8593 bmcgahan@internetworkexpert.com
> > > > >
> > > > > Internetwork Expert, Inc.
> http://www.InternetworkExpert.com Toll
> > > > > Free: 877-224-8987
> > > > > Direct: 708-362-1418 (Outside the US and Canada)
> > > > >
> > > > >
> > > > >
> > > > > > -----Original Message-----
> > > > > > From: nobody@groupstudy.com
> [mailto:nobody@groupstudy.com] On
> > > > > > Behalf Of Bob Sinclair
> > > > > > Sent: Sunday, November 23, 2003 5:05 PM
> > > > > > To: Ken.Farrington@barclayscapital.com;
> ccielab@groupstudy.com
> > > > > > Subject: Re: BGP Soft Reset (BGP RIB)
> > > > > >
> > > > > >
> > > > > > Ken,
> > > > > >
> > > > > > The soft-reconfiguration inbound command is
> required if you
> > > > > > want to issue a
> > > > > > "neighbor received-routes" command. The received routes
> > > > > > command will show
> > > > > > you what the neighbor is sending you BEFORE any inbound
> > > > > > policies are applied. Very helpful!
> > > > > >
> > > > > > HTH,
> > > > > >
> > > > > > -Bob Sinclair
> > > > > > CCIE #10427, CISSP, MCSE bsinclair@netmasterclass.net
> > > > > >
> > > > > > ----- Original Message -----
> > > > > > From: <Ken.Farrington@barclayscapital.com>
> > > > > > To: <ccielab@groupstudy.com>
> > > > > > Sent: Sunday, November 23, 2003 5:05 PM
> > > > > > Subject: BGP Soft Reset (BGP RIB)
> > > > > >
> > > > > >
> > > > > > > Guys,
> > > > > > >
> > > > > > > Please can I confirm that nowadays you do not have
> > to use the "
> > > > > > > neighbor 200.200.1.1 soft-reconfiguration
> inbound" command.
> > > > > > >
> > > > > > > All my routers without this command have the route-refresh
> > > > > > capability
> > > > > > > on (please see output below), and as such and I can do a
> > > > > > >
> > > > > > > "cle ip bgp 200.200.1.1 soft in" or "cle ip bgp
> > > > > > 200.200.1.1 in"
> > > > > > >
> > > > > > > without configuring soft-reconfiguration under the
> > BGP process.
> > > > > > >
> > > > > > >
> > > > > > > Also, I assume the router stores two copies of the
> > RIB, one
> > > > > > > unmodified
> > > > > > and
> > > > > > > one modified with inbound policies. If this is
> > > > correct, is there
> > > > > > > a
> > > > > > > way of showing the unmodified RIB ?
> > > > > > >
> > > > > > >
> > > > > > > TEST2#sh ip bgp nei 200.200.1.1
> > > > > > > BGP neighbor is 200.200.1.1, remote AS 6500,
> external link
> > > > > > > BGP version 4, remote router ID 155.195.16.161
> > > > > > > BGP state = Established, up for 00:06:48
> > > > > > > Last read 00:00:48, hold time is 180, keepalive interval
> > > > > > is 60 seconds
> > > > > > > Neighbor capabilities:
> > > > > > > Route refresh: advertised and received(new)
> > > > > > > <======================Please Note
> > > > > > > Address family IPv4 Unicast: advertised and received
> > > > > > > Received 1481 messages, 936 notifications, 0 in queue
> > > > > > > Sent 1537 messages, 0 notifications, 0 in queue
> > > > > > > Route refresh request: received 0, sent 6
> > > > > > > Default minimum time between advertisement runs
> > is 30 seconds
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > >
> > > >
> > --------------------------------------------------------------------
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