Tag :: ABR

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.

This feature adds the support for OSPFv3 multi-site domains (currently this feature is added for IPv6 address family only) described in RFC6565 (OSPFv3 as a Provider to Customer Edge Protocol for BGP/MPLS IP Virtual Private Networks (VPNs) ) and enables routes BGP VPN routes to retain their original route type if they are in the same OSPFv3 domain. Two sites are considered to be in the same OSPFv3 domain if it is intended that routes from one site to the other be considered intra-network routes.

In an OSPFv2 Area Border Router (ABR), area filters may be used to prevent specific prefixes from being announced by an area as Type 3 Summary LSAs or routes to AS boundary routers as Type-4 ASBR summary LSAs.

In an OSPFv3 Area Border Router (ABR), area filters may be used to prevent specific prefixes from being announced by an