[SR-Users] early media: How to change to tag

[Klaus Darilion]

There is no need to change the tag. GW1 must accept the 200 OK with 
different tag, otherwise the gateway is buggy.

If the gateway is really buggy, the usual workaround is to strip the 
to-tag from the provisional responses, i.e. remove the to-tag from 
Asterisk's 183 response, e.g. using functions from textops module.

regards
Klaus


On 28.03.2012 02:27, Min Wang wrote:
> HI
>
> I am trying to do the early media like this:
>
>
> PSTN/GW1 -> Kamailio -> Asterisk
>
> --> PSTN/GW2
>
> GW1 send invite to Kamilio, Kamilio proxy to Asterisk,
>
> Asterisk reply with 183 ( with to tag=A) and sdp
>
> After the playing some medium, asterisk send 603 reply to Kamailio
>
> Kamilio intercept the 603, and lookup the routing table, decide to send
> invite to GW2.
>
> GW2 reply with 180/200OK with to tag=B
>
> In order to properly proxy the msg to GW1, Kamailio seems need to change
> the to tag from B to A.
>
>
> Is it the right way to do? If so how to change the to tag?
>
> or do I need B2BUA ( only signalling) to do the early media?
>
>
>
> thanks.
>
>
> min
>
>
>
>
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