Choosing a Link to Remote Sites

Once the performance across all available links is known, the CNA system needs a way to instruct the edge routers or other forwarding devices how to route traffic to the remote sites. These two approaches for choosing a link differ primarily in where the configuration effort occurs:

• CNA Link-Group--this configuration option in CNA provides a mapping, using next hop route maps and/or BGP community values, between the network prefixes in use at the remote site and the various site-links that can be used to reach them; see the section “Choosing with CNA Link-Groups”
• Router Route Map--this configuration option adds these next-hop route maps and BGP community values directly on the edge and/or choke routers to correlate network prefixes and links to reach remote sites; see the section “Choosing with Router Route Maps”