The recommended multisite Edge Server topology is similar to the single-site Edge Server topology for the primary site; however, for greater scalability, it has a set of load-balanced consolidated Edge Servers. The remote site has consolidated Edge Servers installed to prevent the introduction of media session delays by routing media through the local site, as shown in Figure 7-3. Because the domain DNS SRV records publish only the primary site (for federation and remote access purposes), the SIP traffic from remote Office Communicator clients always travels through the primary site in this topology. Because SIP traffic does not use as much bandwidth as media traffic, the Access Edge Servers can be managed at the primary site.

Figure 7-3. Multisite Edge Server topology