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Media flow-around problem when the codec is changed to t38



We have a problem about media flow-around. We send a fax from MGCP side to H323 side and the call is established with G729 codec between TG-1 and TG-2. all gw's that is between TG-1 and TG-2 is configured "never route media" also ipipgw is configured "media flow-around". And then CED tone is detected, TG-2 send a Request mode include T38 to switch over T38. And also ipipgw side send a RM to SBC side. MGCP side accept to switch to T38. iptoipgw side send an OLC with T38 codec and its own IP for media. This OLC message is not include TG-2 media IP. So TG-1 send T38 rtp packets to ipipgw's ip and TG-2 send T38 RTP packets to TG-1 directly but no T38 RTP packets are received from TG-1 to TG-2. Because of fax call is failed. Do you know why the iptoipgw behavior like this? Is this a bug? Do you have any suggestion?



Call direction is

Fax Machine == AS 5350XM(TG-1) --MGCP  -- CA --SIP-- SBC --h323--AS5350XM(ip to ip gw) --H323--AS5350XM(TG-2) == Fax Machine 

iptoipgw's IOS version is "Version 12.4(15)T12".

ipipgw's config;

voice service voip 
 media flow-around
 allow-connections h323 to h323
 fax protocol t38 ls-redundancy 0 hs-redundancy 0 fallback pass-through g711alaw


dial-peer voice 2 voip
 permission orig
 description ### General Incoming ###
 preference 10
 service routing
 voice-class aaa 1
 incoming called-number .T
 codec transparent
 ip qos dscp cs3 signaling

dial-peer voice 69 voip
 preference 10
 destination-pattern .T
 voice-class aaa 1
 session target ipv4:x.x.x.x
 codec transparent
 ip qos dscp cs3 signaling


Everyone's tags (6)

Hi. Do you have try to

Hi. Do you have try to disable h245 tunnel?

voice service voip 
  h245 tunnel disable



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