[Users] Angle bracket in Route header coming from Contact and strict router

[Marcello Lupo]

Hi to all,
little question about populating the Route Header field.
I'm dealing with 2 CPE of different vendors (Patton and Netsynt) and an 
Openser in the middle.
Patton in their SIP is not using angle bracket on SIP From,To and 
Contact headers.
Netsynt is using strict routing method to build BYE messages.
This is causing that when Netsynt is creating the BYE it is putting the 
proxy IP in the R-URI and the URI of Contact received from previuos 
packets from patton in the Route header to let it be processed by the proxy.
In this way the Route header field constructed is without the <> 
enclosing the uri. Netsynt keep it from previous Contact without any 
manipulation on it.
This is causing an error on the proxy parsing the name-addr field of the 
Route header field and the loose_route() fail. Seems that it is 
mandatory for Openser to get angle bracket in Route header fields.
Now in the section 20 of RFC3261 is said that it is not a MUST that 
From,To and Contact header have to be enclosed in angle bracket.
So i'm searching in the RFC where is said that if the Contact is without 
the angle bracket the UAC have to check if the Contact have the <> and 
if it don't have the <> it have to insert it before to out it on the 
Route (i searched the RFC2543 too).
can someone give me clarification on this issue?
Where is written the Route header field is mandatory to have <> 
enclosing the URI.
I'm searching all of this because i have to give a good reason to each 
vendor (Netsynt and Patton) to modify their sip stack for this issue. I 
don't know who of the 2 should fix the problem. If Patton to add <> in 
each request or Netsynt to fix the Route field population.
Thanks,
Bye,
Marcello