Limitation for registering Remote Workers

While sending a 301 Moved Permanently response from Session Manager, Avaya SBC does not replace the Session Manager IP address with the external interface IP address. Therefore, endpoints receiving the 301 Moved Permanently response cannot register to the Session Manager.

For example, two Session Managers are configured in Avaya SBC for Remote Worker as follows:

• The first Session Manager is configured with Public interface as A1 and Private Interface as B1

• The second Session Manager is configured with Public interface as A2 and Private Interface as B2

• A user 1234 is configured with the second Session Manager as Primary Session Manager

• The endpoint is configured with IP address of A1 interface as a proxy or registrar server

In this configuration, when the endpoint attempts registration as Remote worker with user 1234, the endpoint sends the REGISTER message to Avaya SBC on the A1 interface. Then, Avaya SBC sends the REGISTER message to the first Session Manager. For this user, the second Session Manager is configured as the Primary Session Manager. Therefore, the first Session Manager sends a 301 Moved Permanently message with the IP address of the second Session Manager in the contact header to the Avaya SBC. However, Avaya SBC forwards the 301 Moved Permanently response to the endpoint without changing the IP address in the contact header. Therefore, the endpoint cannot REGISTER to the second Session Manager.

Limitation for using 96x1 phones as remote users

When a remote worker is behind a NAT, the source IP in the message is different from the media IP published in the SDP message. In such scenarios, Avaya SBC uses media latching to determine the media IP. However, when remote workers behind a NAT only receive media, but do not send media, media latching cannot be used to determine the media IP. To overcome this limitation, the STUN keep alive mechanism is used to determine the media IP. The 96x1 phones do not support STUN keep alive mechanism. Therefore, when a SIP 96x1 phone registers to Avaya SBC as a remote worker user, the phone cannot use the Group Page feature with which media is unidirectional.

Limitation for using third-party SIP endpoints

Avaya SBC does not officially support the registration of third-party SIP endpoints. When used in combination with Avaya applications such as Avaya Oceana®, Avaya Meetings Server, or Avaya Equinox® Meetings Online, Avaya SBC does not support third-party SIP endpoints unless validated by these Avaya offers or applications.

Interaction with Communication Manager administration for music on hold

For remote workers that are administered behind a NAT, the SIP trunks used for the remote workers must have the following Communication Manager options administered to provide music on hold:

• Using the change trunk-group XX command, the TRUNK FEATURES screen on Page 3, you must set the Hold/Unhold Notifications option to no.

• Using the change trunk-group XX command, the PROTOCOL VARIATIONS screen on Page 4, you must set the Network Call Redirection option to no.