[Serusers] Active Passive role supported in UAs

Ladislav Andel ladia6 at centrum.cz
Tue May 16 16:27:29 CEST 2006


It is based on if UA(User Agent) starts relaying RTP packets(active) or 
wait for the first packet from its peer (passive).
It could be used for avoiding RTP proxy when one NAT is involved in the 
session.

For example if public User Agent supports passive role and SER knows it 
then
public UA waits until gets first RTP packet from NATed User Agent, reads 
source IP address/port of the packet
and starts relaying RTP packets to the source IP address/port.. It is 
also called symmetric RTP.
This is the second situation out of three categories I stated.

This practice is also called Connection Oriented Media.

Ladislav

PS: Hard to say if this is being implemented because it is based on 
Internet Draft and it is not standard yet.
I know just that some gateways are supporting it.


Gould, Aaron wrote:
> what is the definition of a active ua and a passive ua?
>  
> thanks
> aaron
>
> ________________________________
>
> From: serusers-bounces at lists.iptel.org on behalf of Ladislav Andel
> Sent: Tue 5/16/2006 4:40 AM
> To: serusers at lists.iptel.org
> Subject: Re: [Serusers] Active Passive role supported in UAs
>
>
>
> Actually, it might be divided into three categories:
>
> 1) UA is advertising its role
> 2) UA is not advertising its role but can be set to be active or passive
> (some Cisco gateways can do it)
> 3) UA can be set by sending a=direction:passive (or active) from SIP
> proxy. This will make the UA passive or active.
>
> Any ideas about this topic?
>
> Ladislav
>
> Ladislav Andel wrote:
>   
>> Hello everybody,
>> I'm sorry for this off topic.
>> I'm trying to make a list of UAs which supports active, passive role.
>> (Regarding connection oriented media or so)
>> These UAs can be gateways, hardphones, softphones, B2BUAs etc.
>>
>> I would appreciate any contribution to my list and thank you,
>> Ladislav
>>
>> _______________________________________________
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>> serusers at lists.iptel.org
>> http://lists.iptel.org/mailman/listinfo/serusers
>>
>>
>>     
>
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