his command enables CUBE to set configuration parameters for outgoing calls based on the received called number. This ensures that both legs of the SIP call use matching codecs. 25. This command defines an alternate SIP trunk for redundant connections to the CUCM cluster. 26. This command defines a SIP Proxy fully qualified domain name (FQDN) for out- bound SIP calls to Verizon. Cisco UCM H.323 Interconnect When using CUCM 3.x, 4.x, or 5.x, using H.323 is the only practical choice to intercon- nect to a SP SIP trunk, as shown in Figure 10-3. Enterprise CUCM 3.x, 4.x, 5.x H.323 SIP (UDP) Figure 10-3 CUCM to SIP Trunk Interconnect Using H.323 When using H.323 to an older CUCM, the SIP side facing the SP's network is the same as shown in Examples 10-1 and 10-2. It is only the interconnection (dial-peer) to the CUCM Chapter 10: Deployment Scenarios 203 that changes. Initiating a SIP Early Offer to the SP SIP trunk requires that CUCM initi- ates an H.323 FastStart. Initiating an H.323 FastStart, in turn, requires that CUCM makes use of a Media Termination Point (MTP). Example 10-3 shows the CUBE configuration connecting to CUCM using H.323. CUCM 4.2 and CUBE 1.0 (IOS 12.4(11)T) are used in this example. Example 10-3 H.323 CUCM to SIP Trunk Interconnect voice service voip allow-connections h323 to sip (1) allow-connections sip to h323 (1) fax protocol t38 Is-redundancy 0 hs-redundancy 0 fallback pass-through g711ulaw h225 connect-passthru voice class codec 1 codec preference 1 g729br8 codec preference 2 g711ulaw interface GigabitEthernet010 description Inside towards CUCM ip address 172.x.x.x 255.255.255.0 duplex auto interface GigabitEthernet0/1 description Outside towards SIP Trunk ip address X.X.X.X 255.255.255.0 duplex auto sccp local GigabitEthernet0/0 (2) sccp ccm 172.x.x.x identifier 1 version 4.1 sccp ccm group 1 (2) associate ccm 1 priority 1 associate profile 1 register MTP0013C4037300 dspfarm profile 1 mtp (2) codec g729br8 maximum sessions software 10 associate application SCCP dial-peer voice 1 voip descri