Hi, MGC is just a UA in SIP network, so it should obey RFC3261. When sending INVITE request, Max-Forwards value is set to be large enough not to be consumed by normal routing in its SIP network, which is 70 by default. When receiving INVITE request, MGC does not care its value as a UAS.
It may be possible to map Max-Forwards into ISUP hop counter parameter and vise-versa in some way to avoid forwarding loop between SIP and ISUP. I do not know the implementation which support the above mapping in any way, though. Hop counter procedure is optional and temporary operation in Q.764 and, I think, is not guarateed in every ISUP network. (For example, Japanese ISUP standard does not support hop counter procedure and hop counter parameter.) I feel that to avoid or detect SIP/ISUP looping is operators' responsibility and how to achive that depends on them. Note that if ISUP encapslation is supported, hop counter mechanism is still valid, if applicable, through ISUP-SIP-ISUP interworking. Regards, Takuya > > Hi, > > Max-Forwards is a mandatory header in SIP INVITE request. However RFC 3398 > (ISUP to SIP Mapping) does not mention what ISUP parameter should be mapped > to Max-Forwards and vice-versa. > > What is the recommended ISUP parameter to map to Max-Forwards header ? > > Thanks, > Kasam > > _______________________________________________ > Sip-implementors mailing list > [EMAIL PROTECTED] > http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors -------- Takuya Sawada KDDI Corporation (KDDI) KDDI Bldg. 2-3-2 Nishishinjuku Shinjuku-ku, Tokyo 163-8003, Japan Tel: +81-3-3347-7406 Fax: +81-3-3347-7418 [EMAIL PROTECTED] _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
