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

omer_srkn
Level 1
Level 1

Hello,

 

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
 h323
 sip
!

 

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

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

 

1 Reply 1

Hi. Do you have try to disable h245 tunnel?

voice service voip 
 h323
  h245 tunnel disable

 

Regards.