asterisk users - Feb 2005 - Bug in SUBSCRIBE handling : running out of RTP ports

While trying to deploy a bunch of Polycom IP 500 phones, I ran in to the
following.  I limited the RTP ports from 8000-8050 to limit holes in
firewall.  Pretty soon Asterisk ran out of RTP ports.  Traced the problem
back to how * is handling SUBSCRIBE.  A sip structure is allocated as soon
as a request is received, which also allocates RTP ports.  Normally, this is
not a problem as the structure is released as soon as the request is
answered, which is pretty quick.  However, SUBSCRIBE has an expiry header,
till which time * keeps around the call structure and hence hanging on to
those RTP ports.  (SUBSCRIBE doesn't even need an RTP port).  This problem
is amplified by Polycom "Buddy Lists" as each phone subscribes to
changes in
extension status of all the "buddy" up to 7 extensions.
 
I just added few lines in handle_request functions to release RTP ports if
it is a subscribe.  Seem to work fine..  Should I send this to Dev list or
somewhere?
 
Hope this helps some one running in to similar problems.
 
Thanks
Sarat.
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Sarat Vemuri wrote:
> While trying to deploy a bunch of Polycom IP 500 phones, I ran in to the 
> following.  I limited the RTP ports from 8000-8050 to limit holes in 
> firewall.  Pretty soon Asterisk ran out of RTP ports.  Traced the 
> problem back to how * is handling SUBSCRIBE.  A sip structure is 
> allocated as soon as a request is received, which also allocates RTP 
> ports.  Normally, this is not a problem as the structure is released as 
> soon as the request is answered, which is pretty quick.  However, 
> SUBSCRIBE has an expiry header, till which time * keeps around the call 
> structure and hence hanging on to those RTP ports.  (SUBSCRIBE doesn't 
> even need an RTP port).  This problem is amplified by Polycom "Buddy 
> Lists" as each phone subscribes to changes in extension status of all 
> the "buddy" up to 7 extensions.
>  
> I just added few lines in handle_request functions to release RTP ports 
> if it is a subscribe.  Seem to work fine..  Should I send this to Dev 
> list or somewhere?
Please add your patch to the bug tracker!
http://bugs.digium.com

Thank you for contributing.

/Olle