Setting The Trunk Group Call Capacity; Inbound Call Routing For A Trunk Group - Linksys RTP300 - Broadband Router With 2 Phone Ports Administration Manual

Setting the Trunk Group Call Capacity

The ITSP may set a limit to the number of calls that can be made on a trunk group. You can
configure a trunk group's call capacity parameter to meet the requirements of the ITSP. Both
incoming call and outgoing calls are counted towards this limit. The call capacity has the
following impact on call handling:
• Inbound calls: When the limit is reached, the Trunk UA replies 486 to the caller.
• Outbound calls: When the limit is reached, the Line UA plays a fast busy tone to the
caller. Note that a trunk line can make an outgoing call only through its own trunk. If
that trunk reaches full capacity, it will not attempt to failover to use other trunks.
You can configure this setting in the Voice tab > Trunk (T1 ... T4) page, Subscriber Information
section, Call Capacity field. For more information, see

Inbound Call Routing for a Trunk Group

An incoming call is handled as follows:
1. When an incoming call is detected by the Trunk UA, the UA first checks if there is capacity to
handle the call. If there is insufficient capacity, the UA rejects the call with a 486 response.
2. If there is spare call capacity, the UA consults the Contact List to determine which line or
lines to ring (that is, for the proxy to send SIP INVITE to), and starts "hunting. " (See
"Configuring a Trunk Group, " on page
3. When a line is selected to ring, one or more PBX phones may be alerted, according to the
PBX features and configuration.
4. The Caller ID of the external Caller is signaled by the Line UA out to the FXS port using the
configured Caller ID method (FSK, DTMF, etc.). The PBX must be able to detect Caller ID
signal in order for the proper Caller ID to show.
5. If the call is picked up by the PBX, the Line UA replies 200 OK with SDP to the internal Proxy.
The Trunk UA in turn replies 200 OK to the ITSP and relay the Line SDP in the 200 OK
message also. If all goes well, the Line UA and the ITSP equipment start exchanging RTP
packets afterwards.
Linksys ATA Administration Guide
SIP Trunking and Hunt Groups on the SPA8000
"Configuring a Trunk Group, " on page
67)
67.
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