Confederation

Route Reflector

Loop prevention

Autonomous system confederation set

Originator or set cluster ID

Break up a single autonomous system

Sub-autonomous systems

Clusters

Redundancy

Multiple connections between sub-autonomous systems

Client connects to several reflectors

External connections

Anywhere in the network

Anywhere in the network

Multilevel hierarchy

Reflectors within sub-autonomous systems

Hierarchical clusters

Policy control

Along outside borders and between sub-autonomous systems

Along outside borders

Scalability

Medium; still requires full IBGP within each sub-autonomous system

Very high

Migration

Very difficult (impossible in some situations)

Moderately easy (impossible in some situations)

In general, route reflectors are simpler to migrate to and relatively simple to use, whereas confederations are more flexible as to IGP and policy.