Intra-site session concentration is done by configuring MSMQ independent clients to use between one and three dedicated MSMQ servers, (InRSs and OutRSs). If an independent client is configured to use an OutRS, every outgoing MSMQ message sent by the independent client is routed to the OutRS. Likewise, if an independent client is configured to use an InRS, every message sent to the independent client is routed through the InRS.
Only MSMQ independent clients can be configured to have either InRSs or OutRSs; MSMQ dependent clients and MSMQ servers cannot be configured to use InRSs or OutRSs. By default, MSMQ independent clients are not configured to use InRSs or OutRSs.
The PEC, PSCs, BSCs, and MSMQ routing servers can all be used as InRSs and OutRSs. The same MSMQ server can be used as an independent client's InRS and OutRS. However, the InRSs and OutRSs must be in the independent client's original site, and must have at least one CN in common. When a user travels to another site with an independent client, InRS and OutRS settings are disabled until the independent client is returned to its original site.
The cost of session concentration is one additional hop for each message and subsequent additional load on the server. The enterprise administrator must determine the best tradeoff between session concentration versus hops and load balancing based on the configuration and network load.
Intra-site session concentration typically reduces network bandwidth usage. For example, if you use a star topology within a site, and each computer usually communicates directly with every other computer, you can greatly reduce your bandwidth usage by using an MSMQ-based application and configuring each MSMQ independent client to use the PSC as its InRS and OutRS.
Figure 1.7
In Figure 1.7 the PSC is being used as both an InRS and an OutRS for each MSMQ independent client. This reduces the total number of possible sessions from 36 to 8.
Because computers configured with InRSs and OutRSs are dependent on the MSMQ server, it is preferable to assign more than one InRS or OutRS to independent clients, to provide failure recovery.
For information on how to specify an independent client's InRS or OutRS, see MSMQ Explorer Help.