[c-nsp] BGP KEEPALIVE maximum frequency

[M. V.]

hi Lukasz,

actually i tested this over 3 different scenarios separately, and the result was 
the same:
(1) in GNS3, i added 2 "cisco3600 (IOS: 12.3(22))" and connected them to 
each-other
(2) in GNS3, i added 2  "cisco3600 (IOS: 12.3(22))", then started  Quagga on 
FreeBSD, then connected my virtual Ciscos to quagga via "tap"s
(3) i connected a Quagga (on FreeBSD) to a real-box "Cisco2800 (ISO: 
12.4(15)T13)" via a real ethernet line

in each scenario, the configuration on each router (quagga, cisco2800, 
cisco3600) was the minimum that is needed:
#interface ???
##ip address X.X.X.Y 255.255.255.0
#router bgp 1
##neighbor X.X.X.Z remote-as 1
##neighbor X.X.X.Z activate

and the result on each scenario was the same:
in (1) both Ciscos were sending 3 KEEPALIVES (after OPENs)
in (2) Quagga and one Cisco sent 2 KEEPALIVES and one Cisco sent 3 KEEPALIVES 
(after OPENs)
in (3) Quagga and Cisco, both sent 2 KEEPALIVES. after that, i restarted Quagga, 
this time, Quagga sent 2 KEEPALIVES and Cisco sent 3 KEEPALIVES.
* i've tested Quagga before and saw Quagga also sends 3 KEEPALIVES sometimes.

this is a sample of my wireshark (just BGPs) for scenario(3) where 192.168.0.24 
is Quagga and 192.168.0.210 is my Cisco2800:
...
no          time            source                dest                 proto    
   info
700    10.198417    192.168.0.24    192.168.0.210    BGP    OPEN Message
701    10.200723    192.168.0.210    192.168.0.24    BGP    OPEN Message
705    10.200855    192.168.0.24    192.168.0.210    BGP    KEEPALIVE Message
706    10.201105    192.168.0.210    192.168.0.24    BGP    KEEPALIVE Message
708    10.201258    192.168.0.24    192.168.0.210    BGP    KEEPALIVE Message
709    10.202348    192.168.0.210    192.168.0.24    BGP    KEEPALIVE Message
712    10.202602    192.168.0.210    192.168.0.24    BGP    KEEPALIVE Message
713    70.204722     .....
...

Regards.





________________________________
From: Łukasz Bromirski <lukasz at bromirski.net>
To: cisco-nsp at puck.nether.net
Sent: Sat, December 4, 2010 4:19:55 PM
Subject: Re: [c-nsp] BGP KEEPALIVE maximum frequency

On 2010-12-04 12:40, M. V. wrote:
> hi,
> 
> i have sort of a technical question.
> RFC4271 (main RFC of BGP4) says: "KEEPALIVE messages MUST NOT be sent more
> frequently than one per second". i checked cisco with wireshark and saw it 
>sends
> more than 1 KEEPALIVE (sometimes 2, but usually 3) in less than 1 second right
> after OPEN messages are sent. and then after that, everything gets back to
> normal, and it sends KEEPALIVEs just every 60 seconds.

Do you have more details on this specific setup? IOS version? Both
devices were Cisco or Cisco<>3rd party? Was it on the real boxes
or under dynamips?

-- "Everything will be okay in the end.  |                 Łukasz Bromirski
If it's not okay, it's not the end." |      http://lukasz.bromirski.net
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