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PacketStar
®
PSAX 2300 Multiservice Media Gateway User Guide
, Issue 1
Release 9.0.0
Chapter 3 System Features
Connections Supported
SVC Functional
Description
SVC signaling, per ATM Forum UNI 3.0 and UNI 3.1, is selectable on a per-
port basis. Call control is performed on the CPU module, including manage-
ment of the call-state transitions for each of the calls. This process allows on-
demand allocation of bandwidth and connection resources. The signaling
protocol supports the following basic functions at the UNI interface:
Call States
Call states exist on both the user side and the network side of the transaction.
Call states define which messages can be accepted by the user or the network
entity, and define how they are expected to react to those messages. As the
user or network entity moves from call state to call state, the call switching
process is accomplished.
In cases where the calling party is the user, and the called party is across the
network, the user-side interface (UNI) at the Multiservice Media Gateway
port presents a UNI to the user. The Multiservice Media Gateway port
receives these user-side messages from the user and—based on resource
availability, route determination, and other network factors—presents a net-
work-side interface (NNI or IISP) to the called party or the network-side
Multiservice Media Gateway port.
Both user-side and network-side interfaces undergo similar state transitions.
Transition messages trigger these call-state changes as follows:
Feature
Description
Connection/Call Setup
With this feature, calls originate and are established.
Connection/Call Request
With this feature, requests of resources for connections to
a certain destination are fulfilled. The Information Ele-
ment (IE) field contains resource information including
PCR, SCR, MBS, and QoS class.
Connection/Call Answer
With this feature, the destination party can respond to a
request with VPI/VCI and other information related to the
connection/call.
Connection/Call Clearing
With this feature, the information associated with remov-
ing the call/connection request is provided. This includes:
1) calls removed because there weren’t enough resources
to meet the call request, 2) connections removed when
call disconnect requests were received from either party,
and 3) calls removed due to link failure and other net-
work failures.
Reason for Clearing
With this feature, the clearing party can indicate the cause
for initiating its removal from a connection/call.