TAT, TRO-CM, and COTs

[jneiberger]

We're running into an interesting problem. Qwest/Nortel has provided an answer but I'm hoping someone here can re-explain it to me in a way that makes sense.

Imagine two sites with Option 11 PBXs. A call comes into Site A on a DID, gets answered and then transferred to Site B, then gets answered and transfered right back to Site A. TRO, or TAT, or some magical mechanism tears down the unnecessary call path to Site B and all is well.

Now, the weird part. In that same scenario, if the original call comes in on a COT, the unnecessary path does not get torn down after the transfer back to Site A.

Qwest and Nortel say this has something to do with some security issue and that COT call paths are not allowed to be modified, but that does not apply to DIDs. I still don't really understand the reasoning.

Do any of you know what the reasoning is behind this?

Thanks,
John

 

[janchundia]

Post:
LD 21
req prt
type net_data

req prt
type rdb
rdb x, y, z (where x, y, z are DID, COT and ISDN routes)

ld 22
req prt
type adan dch

ld 20
req prt
type (did, cot, tie)
tn

Javier

 

[srmega41]

Why does the post of this data matter? I would be interested to know if anyone knows why DID's and COT's are treated differently in call modification scenarios? I realize there are some toll fraud reasons why COT's cannot be modified, but is that still the case with all PBX's and within their own code? Is it also true outside of the vendors and within QSIG, or Q.931?

Nortel documentation states TAT does not function on COT trunks. My question would be why?