Cisco SPA2102-SF Administration Guide - Page 81

Configuring Voice Services SIP Trunking and Hunt Groups on the SPA8000 4 chooses lines in random order (hunt=ra). If a selected line does not answer within 12 seconds (12), the Trunk UA chooses another line at random. If there is no answer after 1 cycle (1), the call is forwarded to forwarded to the specified number (cfwd=14085550123). • ?,hunt=ra;*;1,cfwd=14085550155 A wildcard character is used to represent "all trunk lines." The Trunk UA chooses lines in random order (hunt=ra). The interval is *, meaning the hunt stops when a selected line starts ringing, and will ring the line until it answers, or the caller hangs up, or the line's ringer times out. If the ringer times out, the call is automatically forwarded to the specified number (cfwd=14085550155). Outgoing Call Routing for a Trunk Group Outbound calls on a trunk line are handled as follows: STEP 1 When a PBX phone selects an outside line, the PBX looks for an open line. If the PBX finds an open line, it takes the line off hook and bridges the audio between the PBX phone and the line. On detecting the off hook signal, the SPA8000 Line UA plays dial tone and ready to collect digits from the PBX phone. STEP 2 As the PBX phone user dials the number, the Line UA applies its dial plan to the number. If the Line UA detects an invalid number, it rejects the all by playing reorder tone, then howling tone, then silence. If a valid number is received, it sends a SIP INVITE message to the internal Proxy. STEP 3 The Proxy routes the call to the trunk group UA for the line, and the trunk group UA will attempt to place the call to the ITSP if there is available capacity on the trunk. If there is no call capacity left on the trunk, the internal Proxy will reject the INVITE from the Line UA, which in turn terminates the call and plays reorder tone out to the FXS port. NOTE The SPA8000 will also apply the Trunk Dial Plan on the number before sending out INVITE to the ITSP. This Trunk Dial Plan typically is redundant since the trunk should trust the number sent by the Line UA. By default the trunk dial plan allows any nonempty number: ([*#0-9A-D][*#0-9A-D].) Cisco Small Business ATA Administration Guide 81