Remote Neighbor Session Policy - Cisco ASR 9000 Series Routing Configuration Manual

Implementing EIGRP
Configuring unicast neighbors
However, as the number of forwarders needing to exchange EIGRP information over the networking cloud
increases, unicast EIGRP neighbor definitions may become cumbersome to manage. Each neighbor must be
manually configured, resulting in increased operational costs. To better accommodate deployment of these
topologies, ease configuration management, and reduce operational costs, the Dynamic Neighbors feature
provides support for the dynamic discovery of remote unicast (referred to as "remote neighbors"). Remote
neighbor support allows EIGRP peering to one or more remote neighbors, which may not be known at the
time the device is configured, thus reducing configuration management.
In the topology illustrated below, ASA behaves as a hub and the other routers (2921s, 7010s) act as spokes.
The 2921's and 7010's must not peer with each other, and there must never be a time where a packet (data
traffic) is routed in this path: ASA > 2921.3 > 2921.4. To support this type of network, EIGRP allows you to
configure static neighbors and establish sessions using unicast packet transmission. Thus, in this topology,
2921s and 7010s peer with ASA using neighbor command and ASA is configured to dynamically discover
remote neighbors.

Remote Neighbor Session Policy

When using remote unicast-listen or remote multicast-group neighbor configurations, EIGRP neighbor IP
addresses are not predefined, and neighbors may be many hops away. A device with this configuration could
peer with any device that sends a valid HELLO packet. Because of security considerations, this open aspect
requires policy capabilities to limit peering to valid devices and to restrict the number of neighbors in order
to limit resource consumption. This capability is accomplished using the following manually configured
parameters, and takes effect immediately.
• Neighbor Filter List
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