From: Robert Massiache (robert2140@hotmail.com)
Date: Wed Nov 13 2002 - 18:57:48 GMT-3
Do not take that way...I know it might be confusing a little bit.
The thumb rule is, if you got IGP running inside the AS you might need sync,
otherwise 'no sync'.
In the 2nd case it is assumed that all your routers inside the AS are BGP
running. They can communicate with each other throu IBGP.
Assume a situation like where a 'transit' AS announces to its neighbouring
downstream AS about the routes it has learned from an upstream AS. Now this
transit AS has to be cautious while announcing routes to its downstream
routers. Cautious in what way?
It has to sync its EBGP learned routes(from upstream AS) with its internal
IGP before announcing it to the downstream AS. Otherwise the packets
destined for the upstream AS would get lost at the transit AS.
In essence to avoid packet loss, it is not supposed to announce someone
before its own IGP 'knows' about the routes it has learned.
thanks
>From: "KHAN, IFTIKHAR A" <IKHAN@scana.com>
>Reply-To: "KHAN, IFTIKHAR A" <IKHAN@scana.com>
>To: "'ccielab@groupstudy.com'" <ccielab@groupstudy.com>
>Subject: BGP synchronization
>Date: Tue, 12 Nov 2002 13:13:13 -0500
>
>Group,
> I am confused about BGP synchronization with IGP routing protocols BGP
>should have "no synchronization" when you are not redistributing any
>interior routing protocol with BGP and it should be on if you are
>redistributing with IGP.
>am I right
>
>Confused ????
>
>Thanks
>Iftikhar Khan
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