Nortel Networks NN43001-563 - Manual (Page 76)

76 System description
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
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.
The TM 3.1 User Interface allows two ToS values to be configured: data and
control. Data packets transmit the voice or fax call’s data, while control
packets setup and maintain the call. Both can be configured for any value
in the range of 0 – 255 (0 is the default). When an IP Trunk 3.01 (and
later) node is configured, ToS bits are initially set to default values. The
TM 3.1 IP Trunk 3.01 (and later) node administration interface allows the
customer to configure these bits for potentially better interworking with
different manufacturers’ routing equipment. The extent of any improvement
from setting these ToS bits depends on the network routing equipment.
Improvements can vary depending on the router’s prioritization algorithms.
Nortel Communication Server 1000
IP Trunk Fundamentals
NN43001-563 01.01 Standard
Release 5.0 30 May 2007
Copyright © 2007, Nortel Networks
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