On 15-07-2005 07:25, Dave wrote:

Hi, I am trying to understand the section 5.1.1 (mediaproxy ser.cfg analysis) and I am having trouble understanding RE-INVITES and loose-routing:

Consider following scenario:

UA1 - SER -- P2 - UA2

1. When SER gets a REINVITE from UA1, what happens?

How does SER know it is a REINVITE? Does it work as follows: When SER gets a REINVITE, it checks it's memory to see if an existing TransactionID exists and if yes, then it know that this is a REINVITE?

re-INVITE messages have To tag. Normal INVITEs do not have To tag.

Even if it knows it is a REINVITE, what role does loose_route() play?

re-INVITE messages are sent within an existing dialog and thus they hit the proxy only if the proxy inserted Record-Route header field.

2. WHY does the line 85 on page 40 say

"n order to ensure that we are dealing only with an actual re-INVITE, we must make sure the has_totag() function returns TRUE and loose_route() is also TRUE." Why would the REINVITE have a to_tag()?

See above or RFC3261.

Why must the loose_route return TRUE for RE-INVITES? Won't REINVITES be also record_routed() before reaching the loose_route() directive?

ANy explanations will be appreciated.

Jan.