When connecting the IP Office in the branch to Avaya Aura® Session Manager, you must configure the SIP connection on both systems as follows:

• On the IP Office, the connection to Session Manager is configured as an SM Line. This is a special type of SIP trunk on the IP Office.
• On the Session Manager, the connection to the IP Office is configured as a SIP Entity Link.

SM Lines provide the following additional capabilities in the Branch solution:

• Ability to monitor the SIP connection to Avaya Aura® Session Manager and determine whether the connection is up or down.
• Ability to configure dial plans and prefixes for the branch.

You must obtain SM Trunk Channel licenses for the IP Office to make or receive calls over the SM Line.

IP Office supports two Sessions Managers, a primary Session Manager and a secondary Session Manager, which are each connected through an SM Line. To route calls, you must configure the following routing rules on IP Office and on Avaya Aura® Session Manager:

• On the IP Office, you must configure appropriate IP Office Short Codes and optionally IP Office ARS entries to route calls to the rest of the enterprise through the SM Line. This is not needed to route calls to Centralized users in the branch. IP Office automatically routes these types of calls within the branch in sunny-day mode through the SM Line.
• On the Session Manager, you must configure appropriate Routing Policies and Dial Patterns to route calls to the IP Office in each branch.

Each IP Office system has 2 LAN interfaces, labelled as LAN (LAN 1) and WAN (LAN 2). The SM Lines, as well as connections to IP phones, should be configured to use LAN 1. LAN 2 is primarily intended to connect to the Internet or to public SIP trunks from carriers. You must enable SIP trunks on the LAN 1 configuration in order for the SM Line to use that LAN interface. For more information about configuring SM Lines and other SIP connections, see Deploying Avaya IP Office™ Platform as an Enterprise Branch with Avaya Aura® Session Manager.