Testing SRST

[problemchild27]

                   Hi,

                       Is there a way to test the SRST by creating any type of ACL in CUCM itself. Why am asking is, recently we faced a link flap issue, at the time the gateway was jumping between SRST & MGCP.

Thank you

      PC

[ronpatel]

Hi

You can not create ACL in CUCM. To test SRST you can stop CM service on CUCM and ip phones will fall to SRST. Also you can have ACL configured on branch router to test.

regards

Ronak Patel

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[problemchild27]

Hi,

     Thanks for the response. If i stop the CM service, wont it affect the other branch MGCP gateway & HQ??? Did you mean i can have the ACL configured in the branch MGCP gateway itself???

Thank You

      PC

[ronpatel]

Hi PC,

Yes you can have ACL in branch router to stop SCCP signaing traffic on outgoing WAN interface.

Regards

Ronak Patel

[jonathan.dixon]

I usually add a null route or routes on the branch WAN router, eg:

ip route 255.255.255.255 Null0

This will black hole any traffic destined for the CUCM(s).

[Bruno Rangel]

In add the others comments to MGCP dont forget to TCP 2428, otherwise your phones will go into SRST mode but your gateway will not.

This the ACL you can use to test SRST:

ip access-list extended DENY_VoIPtrafic

deny   tcp any eq 2000 any

deny   tcp any eq 2428 any

deny   udp any eq 2427 any

permit tcp any any

permit udp any any

Please remember to rate helpful  responses and identify helpful or correct answers

Cheers
Bruno Rangel