- Written by Sidharth
- Posted on February 26, 2024
- Updated on October 17, 2024
- 2521 Views
The EOS implementation of OSPF uses an alternate Area Border Router (ABR) behavior. This is implemented as an optimization over the standard OSPF so that the packets would not be dropped when a router loses Active backbone connection which could otherwise be successfully forwarded. As per this new behavior, when an ABR loses active backbone connection, it is allowed to consider summary-lsa from non-backbone area during SPF calculation and the subsequent route installation process thus ensuring improved connectivity. The EOS implementation of OSPFv3 also inherits the same behavior.
- Written by Haris S M
- Posted on August 31, 2023
- Updated on September 4, 2023
- 4495 Views
Configuring OSPF as PE-CE protocol enables us to distinguish between the “real external routes” and intra network routes between the sites that are stretched across VPN. But the problem arises when VPN sites are in the same area and have a backdoor connection. With OSPF as PE-CE protocol redistribution, CE routers end up getting inter-area routes(assuming the VRFs on the PE devices that connect the CE sites, are configured with the same OSPF domain id) that actually belong to the same area and just happen to be multihomed to the backbone.