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Community Member

H.323 Call Preservation

I would like more information on H.323 gateway call preservation. I currently have a 2811 with an E1 PRI. The gateway is configured as an H323 gateway and connected to our Callmanager 4.13 this way (H323 gateway). The gateway is planned to be used as a branch office gateway and therefore it is configured with it own VOIP DHCP pool and Cisco 7961 phones connected to a branch switch. I have simiulated a WAN connection via a Branch firewall to replicated the Branch situation. So visually like this E1 -> 2811 ->Switch with phones -> Firewall -> Callmanager. The 2811 default route is via the firewall. All phones and 2811 are on same VLAN.

I can get an inbound call with an associated dial-peer to route (setup and RTP audio stream) to an SCCP Branch 7961 phone, but when I "bring down" the WAN connection I lose audio both ways (Call is not preserved). The following commands have been issued:

voice class h323 1

h225 timeout tcp establish 3

call preserve

interface FastEthernet0/0

description VOIP

no ip address

no ip mroute-cache

duplex auto

speed auto


interface FastEthernet0/0.200

encapsulation dot1Q 200

ip address

h323-gateway voip interface

h323-gateway voip bind srcaddr

dial-peer voice 20 voip

preference 1

destination-pattern 92....

voice-class codec 2

voice-class h323 1

session target ipv4: (Callmanager)

incoming called-number 9

dtmf-relay h245-alphanumeric

no vad

ip route (Firewall)

It would appear that the RTP audio stream is going to the Callmanager and back. Why would this happen, I assume once the Call Setup is completed the RTP stream should be between the E1 Voiceport and the local IP Phone.

Phones are configured to use the 2811 as default gateway, option 150 is set to retrieve config data from the Callmanager.

Any help would be appreciated.

Thanks, Dennis.

Community Member

Re: H.323 Call Preservation

You may want to try going into the Call Manager Service parameters and changing the Allow Peer to Preserve H.323 Calls from False to True. Check this link out as well.

Community Member

Re: H.323 Call Preservation

This feature is hidden in CallManager 5.x. You must click on the Advanced option at the top of the page to display it.

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