[c-nsp] BGP timer jitter?

[M. V.]

thanks Pete for your answer,

you're quite right, RFC doesn't say one must implement this feature. in RFC2119 
the meaning of SHOULD is defined :

"SHOULD    this word, or the adjective "RECOMMENDED" mean that there may exist 
valid reasons in particular circumstances to ignore a particular item, but the 
full implications must be understood and carefully weighed before choosing a 
different course."

1- timer jitters are very important for routers to prevent congestion, and 
implementation of them are not complicated at all . i know cisco implemented 
jitter in RIP, so there must be a good reason that they didn't implement it in 
BGP. (plus, RFC says there must be a good reason if one doesn't implement one of 
"SHOULD"s). does anyone know what could be the reason? 


2- testing timer jitters are one of the mandatory tests of standard BGP 
Conformance tests, (with conformance testers like Spirent, ...). and if a BGP 
router doesn't have jitter in its timers, it gets a negative point for each 
jitter test (for BGP, we have about 5 tests for different timer jitters). so why 
do they do it when it's not a MUST. shouldn't they just get BGP Conformance 
result based on "MUST" features of RFC?

Cheers!



________________________________
From: Pete Lumbis <alumbis at gmail.com>
To: bored to death <bored_to_death85 at yahoo.com>
Cc: cisco-nsp <cisco-nsp at puck.nether.net>
Sent: Sun, November 21, 2010 6:09:49 AM
Subject: Re: [c-nsp] BGP timer jitter?

I'm not 100% sure, but I don't think it's implemented.  "SHOULD" != "MUST".



On Sun, Nov 21, 2010 at 2:28 AM, bored to death
<bored_to_death85 at yahoo.com> wrote:
> hi everybody,
>
>  i was monitoring cisco's BGP packets and i realized my cisco's BGP keepalive
> packets are being sent out exactly every 60 seconds (with no jitter - with
> maximum 0.001 seconds variance).i looked at BGP main RFC (RFC4271) and it says
> timers should have jitters and says:
>
> "[...] jitter SHOULD be applied to the   timers associated with
> MinASOriginationIntervalTimer,
> KeepaliveTimer,MinRouteAdvertisementIntervalTimer, and ConnectRetryTimer. 
>[....]
> The suggested default amount of jitter SHALL be determined by   multiplying 
the
> base value of the appropriate timer by a random factor, which is uniformly
> distributed in the range from 0.75 to 1.0.    A new random value SHOULD be
> picked each time the timer is set."
>
> so i wanted to know, has cisco implemented timer jitters for different timers 
>(5
> timers) of BGP? if so, do i have to do anything to activate it?
>
> Cheers!
>
>
>
>
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