Suppose this simply scenario: 3 SIP phones A,B,C. On B is set a redirection (moved temporarily) direct to C. On C is set a redirection (moved temporarily) direct to B. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

If A calls B and B replies with moved temporarily to C.

A INVITE B A ---------a B

B “Moved temporarily to C” A s--------- B

A calls C and B replies with moved temporarily to B.

A INVITE C A ---------a C

C “Moved temporarily to B” A s--------- C

A calls B A INVITE B A ---------a B

so it generates an endless loop.

How can I detect and avoid this endless loops?

Does the INVITE contain an header field, analogous to the “Max Forwards”, that I can see to identify a loop and consequently refuse the INVITE?

Thanks for your help,

Daniele