From: Mark Salmon (masalmon@xxxxxxxxx)
Date: Thu Apr 05 2001 - 11:51:37 GMT-3
I have a caveat to the sync question. I would make sure that ALL IP nets (incl
ude the WAN/LAN EBGP) links are reachable by all BGP routers in your AS. The b
eauty about sync is no IP subnets/CIDR nets will appear in the BGP table unless
they appear first in the IGP table. With Sync off (no sync) that will not hap
pen. If your design is not done properly (ie all IP nets in the BGP table incl
ude next hop) is not reachable, then packets will be dropped.
Peter Van Oene wrote:
> Inline comments
>
> *********** REPLY SEPARATOR ***********
>
> On 4/5/2001 at 10:49 AM Oscar Diaz Poveda wrote:
>
> >Dear all,
> >
> >Inside an AS where there are routers that are not running IBPG:
>
> Obviously a stub AS as opposed to a transit? If transit, you should run IBGP
. If full routes internet transit there is no other option here (assuming scal
ability tools like rr's/confeds etc used as well)
>
> >
> >When you should redistribute BGP into the IGP and when you should turn off
> >synchronization???
>
> Synch is only relevant when you run a transit AS and don't' fully mesh with I
BGP. However, you should NOT do this. This is bad. Very bad in fact. If you
are running a transit service, use IBGP and disable synch. Synch is an obsole
te feature that should never be turned on. In fact, I highly doubt that any tr
ansit AS in the world has synch enabled. Further, I suggest that since it has
received little to no programming attention (educated guess) I expect it doesn'
t even work flawlessly. If a proctor asks you to enable synch, I'd call an exo
rcist immediately.
>
> For what its worth, Juniper (who make routers ostensibly for transit as's) do
not even have a knob to enable synch.
>
> Pete
>
> >Thank you for your advice in advance.
> >
> > Best regards,
> >
> >Oscar.
> >
> >
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