====== H.323 Gateway ======

===== Configuration =====

  * Configure T1/E1 interface as in [[gw-t1-e1|T1/E1 Configuration]]
  * Reduce h225 timeout so it won’t timeout the ISDN when failover btw call manager. The example below reduce the failover time to 3s

<code>
voice class h323 1
  h225 timeout tcp establish 3 
</code>

  * Configure POTS Dial Peer
  * With DID, the router/gateway does not present a dial tone to the caller and does not collect digits. It forwards the call directly to the configured destination. This is called one-stage dialing.

<code>
dial-peer voice 1 pots
  destination-pattern .T
  incoming called-number .
  direct-inward-dial
  port 0/1/0:15
</code> 
 
  * Configure VOIP Dial Peer
  * Preference: prefer lower preference

<code>
dial-peer voice 2 voip
  description Subscriber
  preference 1
  destination-pattern 9235....
  session target ipv4:10.59.228.4	
  voice-class h323 1
</code>

===== Advanced =====

  * If H.323 gateway has multiple interface, manually specify the source IP address on the interface. The IP address should match what's configured on the interface.
<code>
interface GigabitEthernet0/0
 h323-gateway voip bind srcaddr <gw-ip>
</code>