We have three sites that are connected in a triangle for redundancy and optimal routing. At present, all three sites are connected using point to point links and routers are using OSPF as the routing protocol beteen the sites. OSPF costs take care of the routing so, packets going from New Hampshire to Florida will traverse the link to Florida and the packets from New Hampshire to Georgia will traverse the link to Georgia. So if one of the links fail, routes will be moved to the other link and all is well.
The issue we are having is when the the link stays up but, the problem is with the Carrier network - the cost of the links don't change. For instance; when traffic is going from New Hampshire to Florida and there is a problem with the Carrier cloud - the OSPF cost won't change so, OSPF will continue to send traffic over that problem link rather than switching to the link to Geogia and then, to Florida.
What is best solution for this issue? IP SLA and tracking?
Not to complicate things but, we will be moving to BGP links from the Carrier and changing over to EIGRP for the internal networks.
The sites will all connected to an MPLS cloud using eBGP. eBGP will be configured on all of our remote routers' Carrier facing interfaces. Then, the BGP will be redistributed into EIGRP (used for internal networks) - and EIGRP will be redistributed into eBGP. When we do this, eBGP will fail over to the other link if say, the Carrier is having issues and a link suddenly has more ASs to traverse (I believe?) but, what about some other types of issues? There are many reasons a link could be less than desirable. Should we think of IP SLAs with this implementation as well?
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