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[CME] External Call Transfer Restrictions

rmajorcz
Level 1
Level 1

Hello,

I have following setup:

  • INTERNAL – telephones registered in CME
  • VOIP_TRUNK – telephones registered in CUCM with sip trunk to CME
  • PSTN line connected on CME

And now I would like to do following:

  1. Internal phone call to internal phone number (within same site), it should be allowed
  2. Internal phone calls a PSTN number, it should be allowed
  3. Internal phone calls to VOIP_TRUNK, it should be allowed
  4. VOIP trunk phone calls to Internal phone (CME), it should be allowed
  5. PSTN (CME FXO lines) to Internal phones (CME), it should be allowed
  6. Internal phone tries to Conference VOIP_TRUNK (phone) & PSTN number, it should not be allowed
  7. Internal phone is on call with VOIP_TRUNK phone and if internal phone tries to transfer calls to PSTN number, it should not be allowed
  8. Internal phone is on call with PSTN and if internal phone tries to transfer calls to VOIP_TRUNK, it should not be allowed
  9. VOIP_TRUNK calls coming to internal phones, should not be forwarded to PSTN number (not allowed)
  10. PSTN calls coming to internal phones, should not be forwarded to VOIP_TRUNK (not allowed)

 

I was already trying to use LPCOR feature or Toll froud prevention but in both cases I have ended up also losing the possibility to transfer/forward/conference between internal (CME users) and PSTN.

 

I know that on CUCM it could probably be achived by External Call Transfer restrictions by classifying calls as on-net off-net, but how can it be achived on CME?

 

thanks and regards,

3 Replies 3

R0g22
Cisco Employee
Cisco Employee
LPCOR are used to implement FAC on CME. You can put restrictions on what patterns can be dialed for transfer, conference etc. Check here -
https://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucme/admin/configuration/manual/cmeadm/cmetrans.html

That is a much better solution.

Hello Nipun,

Thanks for this tip but actually I have already tried it. 

 

Lets say that cme user needs to dial prefix 9 to reach pstn. I configure block transfer pattern 9.T and it indeed blocks transfer of voip trunk (cucm registered end point) from internal (cme registered end point) to pstn. But unfortunately it also blocks possibility of transfer of internal by internal to pstn, what is undesired. 

 

I was also thinking that maybe it could be achieved by using block translation rules on pots dial peer based on transferred caller ID (cucm users are using different extensions). Have you met any solution of such type?

 

regards,

I don't think there are other ways to do it. What you are trying to achieve is too dynamic for the system to comprehend.
Block translations can only be configured in the inbound direction.

You can try and achieve this through COR but that will be too complex and would be a nightmare if you need to troubleshoot something in the future.

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