From: ccie ccie (cciefun@gmail.com)
Date: Sat Dec 08 2007 - 05:06:52 ART
Hi Scott,
Thanks for your reply. I cant do "debug ip rpouting"
1. Because we have lots of OSPF routes in the routing table.
2. If single BGP flap unfortunately the same time when i am doing debugging.
Sure i will have to face BIG problem. So i cant go for this.
Is any other way i can find out the BGP routing loop only using show
command?
Will CPU span wil help?
{ In many cases i have observed that only EBGP session flap when CPU spike
97-99%, IBGP session doesn't flap. Can you please put some light on this.}
Regards
Mike
On 12/8/07, Scott Morris <smorris@ipexpert.com> wrote:
>
> Do a "debug ip routing" on the 6500's. If you are just getting a default
> route, not that much should change. However, I think you have introduced a
> BGP routing loop. You'll see some messages about which route is causing
> recursion and therefore killing the sessions if I'm right.
>
> Scott
>
>
>
> ------------------------------
> *From:* ccie ccie [mailto:cciefun@gmail.com]
> *Sent:* Friday, December 07, 2007 10:01 PM
> *To:* smorris@ipexpert.com
> *Subject:* Re: Real world Scnario...Need Help...Lossing $$$
>
>
> Hi All,
>
>
> What SUP are you running on the 6500's? ==> Sup 720
>
> how much memory? Not in office need to check that but sure more more than
> 128MB. They have set good standard for memory/enggeering IOS etc.
>
> What does "sh proc cpu" look like? EBGP hold time expire (hello 2 , hod
> time is 6sec) & its come up immegiately. In "sh proc cpu his" the flap time
> matches to cpu spike. CPU spike when flap happen mostly between 97-99% only
> for few second.
>
> Are you getting any log messages on your switch (e.g. are you SURE you
> aren't getting full routes or trying to?)--Only default BGP route from
> Juniper router.
>
> What i have checked,
>
> 1. BW on link to Juniper & Core sw 2 is OK
> 2. CPU is 20% all time mostly
> 3. Log all clear except BGP hold timer expire when flap
> 4. No input output interface drop on Core sw2 to juniper interface
> 5. IBGP session between both switches, never falp. Only EBGP session flap
> with BOTH juniper. ( So juniper is not culprit as usual.)
> 6. I suspect some kind of traffic from LAN or WAN hitting causing the few
> second spike in CPU which turn to EBGP session flap on core switch 2. My
> observation in all DC of my company, whenever the CPU hits to 97-99% only
> EBGP session flap & IBGP as well as OSPF keep clam.
>
> The reason EBGP flap is due to MTU mismatch on uplink that is also not
> there.
>
> Thanks in advance for any kind on help.
>
> Regards,
> Mike
>
>
>
>
>
>
>
>
> On 12/8/07, Scott Morris <smorris@ipexpert.com> wrote:
> >
> > What SUP are you running on the 6500's? how much memory? What does "sh
> > proc cpu" look like? Are you getting any log messages on your switch (
> > e.g.
> > are you SURE you aren't getting full routes or trying to?)
> >
> > Scott
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto: nobody@groupstudy.com] On Behalf Of
> > ccie
> > ccie
> > Sent: Friday, December 07, 2007 12:42 PM
> > To: Cisco certification
> > Subject: Real world Scnario...Need Help...Lossing $$$
> >
> > Hi Tech Lover,
> >
> > Juniper R1
> > Juniper J2 <---- Connect to
> > BB
> > router as well as this router face the internet world.
> > | | / / \ \
> > | | <--- Each
> > EBGP
> > session with hello 2 Hold 6 running on each physical link. OPSF is also
> > running on same link.
> > Server Iron LB ======= 6500 sw1 ---ibgp---
> > 6500 sw2 ====Server Iron LB
> > | | / / \ \
> >
> > | | <--- Physical
> > link are L2 port channel
> > 4948 sw1 4948
> > sw2
> >
> >
> >
> > This is an scnario, where i need your help. We cant run EBGP on loopback
> >
> > due to some architecturial concern. Problem with only EBGP session on
> > core
> > sw2.
> >
> > Our EBGP session only on core switch 2 with Juniper 1 & 2 flap with few
> > irregular hours. IBGP session between core switch 1 & 2 never flap. We
> > are
> > get hell lot of traffic. This site run multicast ( but sure that could
> > not
> > be problem) servers, web server, DB server etc. Core sw1 session are
> > always
> > stable. OSPF neighborship on both switch to Juniper BB router is up
> > snce
> > more than 1 yrs.
> >
> > 1. BW on link is not high.
> > 2. CPU show 99% spike when BGP falp. CPU cause BGP flap i think so. ( I
> > dont
> > think BGP flap can cause of CPU spike.)
> > 3 Core switch is not having full BGP route.
> >
> > ( i tried to put ip nabr protocol-discover on EBGP link & session flap
> > due
> > to me, i revert back in few sec to save my job)
> >
> > Suggest an troubleshooting step. As usual TAC is already open & CISCO
> > taking
> > too much time.
> >
> > Regards,
> > Mike
> >
> > _______________________________________________________________________
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> > http://www.groupstudy.com/list/CCIELab.html
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