From: Howard C. Berkowitz (hcb@gettcomm.com)
Date: Fri Nov 28 2003 - 21:26:46 GMT-3
At 4:56 PM -0500 11/28/03, Scott Morris wrote:
>It's my impression that the databases are set up in a particular fashion
>by the soft-reconfig command, regardless of whether you are or are not
>doing any particular filtering.
>
>How much memory is on your router(s)? Were you having any difficulties
>accepting all of the routes before?
>
>Short of going to a default route from your provider, you may consider a
>prefix-list idea (perhaps on their end if they will ponder it for you)
most easily if you both support Outbound Route filtering.
>to prevent routes of, say more specific than /20 from being sent to you,
>or being accepted on your end.
>
>I would be interested in the output of "show ip bgp summary" both with
>and without the soft-reconfig options... That'll tell a bit about the
>memory being used and how many entries et al. At least if you feel like
>resetting and/or rebooting things again! :)
>
>Scott
>
>-----Original Message-----
>From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
>Anthony Pace
>Sent: Friday, November 28, 2003 2:21 PM
>To: Scott Morris; 'Brian McGahan'; 'Jim Devane'; ccielab@groupstudy.com
>Cc: cchurch@wamnetgov.com; marcelo.medina@citigroup.com
>Subject: Why Disabling BPG soft-reconfig did not reclaim Memory?
>
>
>I saw this thread and it was in vien of my situation. I had 2 production
>routers doing soft-reconfig and were at 90% memory utilization. They
>were taking in full tables from two providers(1 each). I removed
>soft-reconfig from both configs, cleared BGP and even rebooted routers
>but after they converged they were still using 90% memory.
>
>I now cannot view received routes, validating that the "untouched table
>is gone", but the memory utilization is identical.
>
>Is it possibel that instead of storing 2 tables, perhaps the router
>marks certain routes or indexes it some how to accomodate your filters?
>I was not really filtering it so maybe it never stored a second table?
I don't know how Cisco has implemented the BGP tables. In at least
two code implementations where I have seen the code, the
interface-level RIBs and the Loc-RIB are all in the same structure,
appropriately flagged.
>
>My next step is to only take in partial routes (my neigbor's neigbors)
>
>Tony Pace
>
>
>On Mon, 24 Nov 2003 16:17:11 -0500, "Scott Morris" <swm@emanon.com>
>said:
>> 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
>> > > > > the Barclays
>> > > > > > > > Group does not accept legal responsibility for the
>> > > > > contents of this
>> > > > > > > > message. Although the Barclays Group operates
>> > > > > > > > anti-virus
>> > > > > > > programmes,
>> > > > > > > > it does not accept responsibility for any damage
>> > > > > whatsoever that
>> > > > > > > > is
>> > > > > > > > caused by viruses being passed. Any views or opinions
>> > > > > > > presented are
>> > > > > > > > solely those of the author and do not necessarily
>> > represent
>> > > > > > > those of
>> > > > > > > > the Barclays Group. Replies to this email may be
>> > > > > monitored by the
> > > > > > > > > Barclays Group for operational or business reasons.
>> > > > > > > >
>> > > > > > > >
>> > > > > > >
>> > > > >
>> > > ------------------------------------------------------------------
>> > > --
>> > > > > > > --
>> > > > > > > > --
>> > > > > > > >
>> > > > > > > >
>> > > > > > >
>> > > > >
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>> _
>> Please help support GroupStudy by purchasing your study materials
>from:
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>--
> Anthony Pace
> anthonypace@fastmail.fm
>
>--
>http://www.fastmail.fm - Same, same, but different
>
>_______________________________________________________________________
>Please help support GroupStudy by purchasing your study materials from:
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