Re: [nsp] REG: OSPF routes

From: Vinod Anthony Joseph Cherunni (vac@dsqworld.com)
Date: Mon Jan 08 2001 - 04:54:56 EST


Thanks a lot for the advice, I think I have been unclear with the language
I have used. Sorry for that.

To Clarify a little more.

The primary static route used on both the routers (A, B) refer to two
links connected to an Upstream ISP within the country. Therefore we intend
to push a majority of our Internet traffic through both these circuits.
This upstream ISP does not pass internet routes to us as a policy. But we
still announce our routes through BGP with an aggregate, & as well as few
specific prefixes to also influence the incoming traffic to enter our
network via this ISP.

The Secondary static route on both the routers (A, B) refer to two links
connected to an Upstream International ISP. We plan to use this bandwidth
predominantly for MPLS VPN traffic for a lot International customers, &
thereby would prefer to use the circuits, only if the primary links on
both the routers are down. I understand this is possible because even if
one router's primary link fails, It would use the OSPF propogated default
which has a lower administrative distance than the secondary static route
configured locally with an administrative distance of 150. Also to mention
is the fact that we are not accepting Internet routes sent by the
International ISP, because of the need that we need to use the primary
links first & only in need of redundancy the International links. Only
aggregate routes will be announced upstream via the International
provider, affecting the incoming traffic to use these links only when the
links to the national ISP are down.

But the only concern is that, assume that the primary link on both the
routers to the National ISP are down. Then each of the router will start
using the default OSPF propogated route sent by the other. The output here
would be that router A will send all Internet traffic to router B, which
will use its secondary (International link) to forward traffic, & vice
versa. In this scenario I would prefer that each router use its locally
available secondary circuit if available, thus saving on Inter-POP
bandwidth between the two routers, & achieve better load distribution on
the International links for outgoing Internet traffic.

Kindly advice on this.. Just assuming on whether some method, wherein
administrative distance on the default OSPF routes can be manipulated &
increased , or decreased based on the status of the primary link on each
router.

Thanks & warm regards,
Vinod.



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