AudioCodes Mediant 4000 SBC User Manual page 361

User's Manual
Parameter
User UDP Port Assignment
user-udp-port-
assignment
[IPGroup_UserUDPPortAssi
gnment]
Version 7.2
request for that user was routed. In other words, once initial
registration of the user to one of the IP addresses of the Proxy Set
associated with this destination Server-type IP Group is successful
(i.e., 200 OK), binding occurs to this specific address (registrar)
and all future SIP requests from the user are routed (based on
matched routing rule) only to this specific registrar.
Note:

The parameter is applicable only to Server-type IP Groups.

The Proxy Set associated with the Server-type IP Group must be
configured with multiple IP addresses (or an FQDN that resolves
into multiple IP addresses).

This feature is also applicable to IP Group Sets (see Configuring IP
Group Sets on page 523). If a user is bound to a registrar
associated with this Server-type IP Group which also belongs to an
IP Group Set, IP Group Set logic of choosing an IP Group is
ignored and instead, the device always routes requests from this
user to this specific registrar.

A user's "stickiness" to a specific registrar ends upon the following
scenarios:

If you modify the Proxy Set.

If the Proxy Set is configured with an FQDN and a DNS
resolution refresh removes the IP address to which the user is
bound.

User registration expires or the user initiates an unregister
request.

The Proxy Set's Hot-Swap feature (for proxy redundancy) is not
supported for users that are already bound to a registrar. However,
you can achieve proxy "hot-swap" for failed initial (non-bounded)
REGISTER requests. If a failure response is received for the initial
REGISTER request and the response's code appears in the
Alternative Routing Reasons table (see Configuring SIP Response
Codes for Alternative Routing Reasons onn page 516), "hot-swap"
to the other IP addresses of the Proxy Set is done until a success
response is received from one of the addresses. In the case of
failed REGISTER refresh requests from users that are already
bound to a registrar, no "hot-swap" occurs for that request; only for
subsequent refresh requests.

When using the User Info table (see SBC User Information for SBC
User Database on page 635), registrar "stickiness" is supported
only when the user initiates the REGISTER request. Therefore, you
must configure the 'Registration Mode' parameter of the IP Group
(User-type) to which the user belongs, to User Initiates
Registration.

This feature is also supported when the device operates in HA
mode; registrar "stickiness" is retained even after an HA
switchover.
Enables the device to assign a unique, local UDP port (for SIP
signaling) per registered user (User-type IP Group) on the leg
interfacing with the proxy server (Server-type IP Group). The port is
used for incoming (from the proxy to the user) and outgoing (from the
user to the proxy) SIP messages. Therefore, the parameter must be
enabled for the IP Group of the proxy server.

[0] Disable = (Default) The device uses the same local UDP port for
361
Description
17. Control Network
Mediant 4000 SBC