On Monday 14 January 2008 10:16:00 Mahesh_Pidshetty wrote:
> Hi all,
>
> I am bit bemused with the parameter maddr.
>
> I would be glad if someone delineate the exact meaning and usage of maddr
> parameter.
>
> The remaining test cases are pending for our company product because of
> not getting clear picture of maddr parameter.
>
> I am looking fwd.
"maddr" is used for multicast.
RFC3261:
16.4 Route Information Preprocessing
...
If the Request-URI contains a maddr parameter, the proxy MUST check
to see if its value is in the set of addresses or domains the proxy
is configured to be responsible for. If the Request-URI has a maddr
parameter with a value the proxy is responsible for, and the request
was received using the port and transport indicated (explicitly or by
default) in the Request-URI, the proxy MUST strip the maddr and any
non-default port or transport parameter and continue processing as if
those values had not been present in the request.
A request may arrive with a maddr matching the proxy, but on a
port or transport different from that indicated in the URI. Such
a request needs to be forwarded to the proxy using the indicated
port and transport.
16.5 Determining Request Targets
...
If the Request-URI of the request contains an maddr parameter, the
Request-URI MUST be placed into the target set as the only target
URI, and the proxy MUST proceed to Section 16.6.
18.1.1 Sending Requests
...
A client that sends a request to a multicast address MUST add the
"maddr" parameter to its Via header field value containing the
destination multicast address, and for IPv4, SHOULD add the "ttl"
parameter with a value of 1.
18.2.2 Sending Responses
...
* Otherwise, if the Via header field value contains a "maddr"
parameter, the response MUST be forwarded to the address listed
there, using the port indicated in "sent-by", or port 5060 if
none is present. If the address is a multicast address, the
response SHOULD be sent using the TTL indicated in the "ttl"
parameter, or with a TTL of 1 if that parameter is not present.
19.1.1 SIP and SIPS URI Components
...
The maddr parameter indicates the server address to be
contacted for this user, overriding any address derived from
the host field. When an maddr parameter is present, the port
and transport components of the URI apply to the address
indicated in the maddr parameter value. [4] describes the
proper interpretation of the transport, maddr, and hostport in
order to obtain the destination address, port, and transport
for sending a request.
The maddr field has been used as a simple form of loose source
routing. It allows a URI to specify a proxy that must be
traversed en-route to the destination. Continuing to use the
maddr parameter this way is strongly discouraged (the
mechanisms that enable it are deprecated). Implementations
should instead use the Route mechanism described in this
document, establishing a pre-existing route set if necessary
(see Section 8.1.1.1). This provides a full URI to describe
the node to be traversed.
--
Iñaki Baz Castillo
[EMAIL PROTECTED]
_______________________________________________
Sip-implementors mailing list
[email protected]
https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
