[33477] in North American Network Operators' Group
RE: BGP keepalive/holdtime at GigE exchange
daemon@ATHENA.MIT.EDU (Lane Patterson)
Fri Jan 12 13:57:59 2001
Message-ID: <4FA6CECCC8A3D41186F700B0D0784FF4054DE2@hq-exchange.corp.equinix.com>
From: Lane Patterson <lpatterson@equinix.com>
To: "'nanog@merit.edu'" <nanog@merit.edu>
Date: Fri, 12 Jan 2001 10:49:02 -0800
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Hmm, many folks didn't seem to understand the context here.
fast-external-fallover doesn't apply if a peer BR across a GigE
exchange dies...you've still got link on your Gig port, so there
is no link level indication of failure.
tweaking tcp timers is not the right approach...BGP explicitly
has a keepalive for this exact purpose, when peering dies but
your interface stays up.
the best non-radical suggestion so far is to simply tweak your
keepalive to 10 and holdtime to 30 seconds, to bring this in line
with the granularity of direct-connected peer interface or IGP metrics.
Do people do this? Do people have problems doing this?
Do any folks do less than this on their eBGP peers, and at
what tradeoff expense.
This is the old issue of finding the right operationally sane
timeouts, not too high, not too low. The defaults clearly
seem too high, yet I haven't seen many cases where folks set
these down :-)
Cheers,
-Lane
> -----Original Message-----
> From: Lane Patterson [mailto:lpatterson@equinix.com]
> Sent: Thursday, January 11, 2001 10:08 PM
> To: 'nanog@merit.edu'
> Subject: FW: BGP keepalive/holdtime at GigE exchange
>
>
>
>
>
> I am looking for operational BCP feedback on common practice
> for tweaking
> down BGP holdtime/keepalive across GigE exchange points, since a peer
> could go down on the other side of the GigE switch without a
> corresponding adjacency change seen on your BR. The thought is
> to make down peers known as fast thru a GigE exchange as they would
> be over a POS private peer interface.
>
> The current defaults are pretty gross, and much worse than the
> ISIS hello and interface keepalive defaults of 10 seconds.
>
> IOS12.x: neighbor [ip-address | peer-group-name] timers
> keepalive holdtime
> holdtime: default 180 seconds
> keepalive: default 60 seconds
>
> http://cco.cisco.com/univercd/cc/td/doc/product/software/ios12
> 1/121cgcr/ip_r
> /iprprt2/1rdbgp.htm#xtocid8553
>
> JunOS 4.2:
> holdtime: default 90 seconds
> keepalive: default one third of holdtime
>
> https://www.juniper.net/techpubs/software/junos42/swconfig-rou
> ting42/html/bg
> p-summary13.html#1015669
>
> Cheers,
> -Lane
>
> Lane Patterson <lane@equinix.com>
> Equinix, Inc.
>
