Return To The Ip Network; Type Of Service - Nortel 1000 Description, Installation And Operation Manual

System description Page 105 of 644
As a result, for all calls going to the Gatekeeper, such as in IP Peer
Networking, no fallback can occur. The call either goes through with possibly
a lower QoS, or the call clears instead of falling back. All QoS control is in
the hands of the Gatekeeper.
However, for calls using the ATPM static address tables, the IP Trunk 3.01
(and later) Leader retains awareness of network status and can cause fallback
to the PBX, if needed.
The full QoS fallback function is available for locally provisioned addresses.
IP Peer and Qos
The IP Peer Networking nodes do not support QoS monitoring. The
capability must be enabled for both sides in order for it to work, but it cannot
be enabled for IP Peer Networking. Therefore, do not enable QoS monitoring
for any numbers terminating on an IP Peer Networking node. If this is done,
the IP Peer Networking node is unreachable for that IP Trunk 3.01 (and later)
node.
IP Trunk 3.01 (and later) nodes can perform QoS monitoring only on remote
IP Trunk 3.01 (and later) nodes provisioned locally with SL1, SL1 with
ESN5, or CS 1000S node capabilities.

Return to the IP network

Unless the DCH is down and all trunks appear busy to the system, outgoing
calls are introduced to the IP Trunk 3.01 (and later) node. Each call is tested
against the outgoing address translation and Quality of Service (QoS) for the
destination node. After the QoS returns to an acceptable level, all new
outgoing calls are again routed through the IP network. The call connections
that were established under the fallback to alternate facilities condition are not
affected.

Type of Service

The IP packet handler has a byte of data for Type of Service (ToS). This byte
allows the user to indicate a packet's priority so that routers can more
efficiently handle data packets. For example, a router can decide to queue low
priority data while immediately passing packets marked as high priority.
IP Trunk Description, Installation, and Operation