Media5 Mediatrix 4104, Reference Manual

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Chapter 18 - SIP Protocol Features Authentication
260 Mediatrix 4104
Background Information
The following explains how the session timers are used.
SDP in Session Timer reINVITEs
The reINVITE is sent with the last SDP that was negotiated. Receiving a session timer reINVITE should not
modify the connection characteristics.
Relation Between Minimum and Maximum Values
A user agent that receives a Session-Expires header whose value is smaller than the minimum it is willing to
accept replies a “422 Timer too low” to the INVITE and terminates the call. The phone does not ring.
It is up to the caller to decide what to do when it receives a 422 to its INVITE. Mediatrix units will automatically
retry the INVITE, with a
Session-Expires value equal to the minimum value that the user agent server was
ready to accept (located in the Min-SE header). This means that the maximum value as set in the Mediatrix
unit might not be followed. This has the advantageous effect of establishing the call even if the two endpoints
have conflicting values. Mediatrix units will also keep retrying as long as they get 422 answers with different
Min-SE values.
Who Refreshes the Session?
Re-sending a session timer INVITE is referred to as refreshing the session. Normally, the user agent server
that receives the INVITE has the last word on who refreshes. Mediatrix units always let the user agent client
(caller) perform the refreshes if the caller supports session timers. In the case where the caller does not
support session timers, the Mediatrix unit assumes the role of the refresher.
Authentication
Authentication information allows you to add some level of security to the Mediatrix 4104 lines by setting user
names and passwords. You can add two types of authentication information:

line-specific authentication

unit authentication
When a realm requests authentication, the line-specific authentication is tried first, and then the unit
authentication if required.
You can also set these parameters via the web interface, as described in “SIP Authentication” on page 69 .
Line-Specific Authentication
You can define up to five user names and five passwords for each line of the Mediatrix 4104. A line can thus
register with five different realms. Keep in mind that:

Rows 1-5 of the table where you define the user names and passwords are reserved for line 1.

Rows 6-10 of the table where you define the user names and passwords are reserved for line 2.

etc.
For instance, to enter a user name for the second line, you must do so in the sixth row of the table. To enter
a user name for the third line, you must do so in the eleventh row of the table, and so on.
Standards Supported Basic and Digest authentication as per RFC 3261