AudioCodes Mediant 4000 SBC, User Manual

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CHAPTER 60 Configuration Parameters Reference
Mediant 4000 SBC | User's Manual
Parameter Description
■ If more than two P-Preferred-Identity headers are received in the
incoming message, the device keeps the first two headers (if
configured to 0) or the first header (if configured to 1), and
removes the others in the outgoing message.
'GRUU'
configure voip >
sbc settings >
enable-gruu
[EnableGRUU]
Determines whether the Globally Routable User Agent URIs
(GRUU) mechanism is used, according to RFC 5627. This is used
for obtaining a GRUU from a registrar and for communicating a
GRUU to a peer within a dialog.
■ [0] Disable (default)
■ [1] Enable
A GRUU is a SIP URI that routes to an instance-specific UA and
can be reachable from anywhere. There are a number of contexts in
which it is desirable to have an identifier that addresses a single UA
(using GRUU) rather than the group of UA’s indicated by an Address
of Record (AOR). For example, in call transfer where user A is
talking to user B, and user A wants to transfer the call to user C.
User A sends a REFER to user C:
REFER sip:C@domain.com SIP/2.0
From: sip:A@domain.com;tag=99asd
To: sip:C@domain.com
Refer-To: (URI that identifies B's UA)
The Refer-To header needs to contain a URI that user C can use to
place a call to user B. This call needs to route to the specific UA
instance that user B is using to talk to user A. User B should provide
user A with a URI that has to be usable by anyone. It needs to be a
GRUU.
■ Obtaining a GRUU: The mechanism for obtaining a GRUU is
through registrations. A UA can obtain a GRUU by generating a
REGISTER request containing a Supported header field with the
value “gruu”. The UA includes a “+sip.instance” Contact header
parameter of each contact for which the GRUU is desired. This
Contact parameter contains a globally unique ID that identifies
the UA instance. The global unique ID is created from one of the
following:
✔
If the REGISTER is per the device’s client (endpoint), it is
the MAC address concatenated with the phone number of
the client.
✔
If the REGISTER is per device, it is the MAC address only.
✔
When using TP, “User Info” can be used for registering per
endpoint. Thus, each endpoint can get a unique id – its
phone number. The globally unique ID in TP is the MAC
address concatenated with the phone number of the
endpoint.
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