This is another proposal for the multi-branch architecture. The major difference from previous proposals is that the "Backup Router" has been turned into a proxy/router pair. This change allows this "auxiliary" pair to function effectively as an HA partner of every branch's proxy/router pair(s), allowing the system to provide redundancy via SRV processing rather than via additional Contacts generated in 302 responses. This removes much of the extra message traffic and allows managing the system more like simple sipXecs installations.
The "central branch" has a sipXconfig which manages all the sipXecs components in the system. Each branch (including the central branch, which is much like any other branch) is provided with a SIP subdomain. E.g., branch1.xxx, branch2.xxx. Each branch has one or more proxy/router pairs on a series of hosts. E.g., host1-1.branch1.xxx, host1-2.branch1.xxx, host1-3.branch1.xxx, host 2-1.branch2.xxx. These hosts may be low-powered, as they will handle only traffic to/from phones/services for which this is the home branch. They will be configured to consider their branch's SIP subdomain as their domain, with the main SIP domain as an alias. They are configured with aliases to route every SIP user for which they are not the home branch to the home branch of the user. There are one or more "auxiliary" proxy/router pairs on a series of hosts. E.g., host1.aux.xxx, host2.aux.xxx. These hosts are high-powered, since they will replicate all registrations and may handle traffic for users with any home branch. They are *not* configured with aliases for SIP users. (Only SRV records internal to the enterprise network are considered here.) For each branch, its proxy/router pairs, and all auxiliary proxy/router pairs, are configured as SRV targets for the branch's subdomain. The auxiliary pairs are less preferred than the branch pairs. The main SIP domain is provided with SRV records that specify one or more proxy/router pairs. These are not normally used for routing, since *every* UA (phone and service) is configured with its home branch subdomain as its outbound proxy. Each user is assigned a "home branch". Any UA appearance for that user is configured with its home branch subdomain as its outbound proxy. (UA's that may be used outside the enterprise network are considered later.) Registrar-based services (user forwarding, voicemail processing) for a user are configured for the user's home branch's registrar(s), but no others. (Or, if the auxiliary hosts have sufficient power, they may be configured with these services as well.) Services are partitioned among branches. Services which are specific for a user (e.g., BLF subscription server) are allocated to a service process on the host(s) of the user's home branch. Other services (e.g., paging group processing, park orbits) are allocated to a service process on host(s) chosen for efficiency/reliability -- usually the host(s) of the home branch of the majority of the service's users or targets. In regard to externally-visible SIP domains and their SRV records: The enterprise domain has external SRV records for the public addresses of the proxy/registrar(s) of the "central branch". The central branch provides services seen by outside callers (e.g., the main autoattendant). Other branches may have external SRV records for the branch SIP subdomain. These SRV records target the public addresses of the proxy/registrar(s) of the branch. (Note that these public addresses may be just additional listening ports on the enterprise gateway, forwarded to the appropriate hosts.) Any user appearance on a UA that is used outside the enterprise network must have a home branch that has external SRV records. (This may restrict the set of branches available as home branches for "remote workers".) Dale _______________________________________________ sipx-dev mailing list [email protected] List Archive: http://list.sipfoundry.org/archive/sipx-dev Unsubscribe: http://list.sipfoundry.org/mailman/listinfo/sipx-dev sipXecs IP PBX -- http://www.sipfoundry.org/
