From: Jim Devane (jim@powerpulse.cc)
Date: Mon Nov 24 2003 - 18:23:49 GMT-3
Gotcha.... makes sense. I will reset my peers on Wed night and summarize to
see if there was in fact any memory resources freed up. I agree, 2:1 would
be great! But I am not that optimistic.
-----Original Message-----
From: Scott Morris [mailto:swm@emanon.com]
Sent: Monday, November 24, 2003 1:17 PM
To: 'Brian McGahan'; 'Jim Devane'; ccielab@groupstudy.com
Subject: RE: BGP Soft Reset (BGP RIB)
That's because the "policy" of being able to do a soft reset is
something that has to be set up in the database at the beginning of a
peering arrangement. So whenever you add it, the database needs to be
refreshed accordingly. Extra chunks of the database are used to be able
to do on-the-fly processing of the soft-reset.
It's not so much that memory is held (the way we normally think of
applications), but more that the BGP database is allocated differently
in order to allow for better parsing, so that takes up memory. In my
experience, it hasn't necessarily been a 2:1 increase like someone else
had mentioned, but it may cause issues on otherwise over-laden routers.
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713,
CISSP, JNCIS, et al.
IPExpert CCIE Program Manager
IPExpert Sr. Technical Instructor
swm@emanon.com/smorris@ipexpert.net
http://www.ipexpert.net
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Brian McGahan
Sent: Monday, November 24, 2003 3:52 PM
To: 'Jim Devane'; ccielab@groupstudy.com
Subject: RE: BGP Soft Reset (BGP RIB)
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
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > >
> > > >
> > --------------------------------------------------------------------
> > > > > > --
> > > > > > > --
> > > > > > > For more information about Barclays Capital, please visit
> > > > > > > our web site at http://www.barcap.com.
> > > > > > >
> > > > > > >
> > > > > > > Internet communications are not secure and therefore
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> > > > > > > Group does not accept legal responsibility for the
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> > > > > > > message. Although the Barclays Group operates anti-virus
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> > > > > > > it does not accept responsibility for any damage
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> > > > > > > is
> > > > > > > caused by viruses being passed. Any views or opinions
> > > > > > presented are
> > > > > > > solely those of the author and do not necessarily
> represent
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