158 ITG engineering guidelines
TLAN subnet design
The IP Trunk3.01 (and later) nodes must connect to the intranet to minimize
the number of router hops between the systems if there is adequate
bandwidth on the WAN links for the shorter route. This reduces the fixed
and variable IP packetdelay, and improves the voice QoS.
If a mixed-codec IP Trunk3.01 (and later) network, or a non-default payload
size or fax settings is used, then use the LAN bandwidth consumption
in Table17 "Silence Suppression disabled TLAN Ethernet and WAN IP
bandwidth usage per IP Trunk3.01 (and later) " (page 113) to estimate the
amount of LAN bandwidth used by each card.
The TLAN network interface must connect to a 10/100BaseT switch. The
uplink from the TLAN network interface to the router should be at least 100
Mbps. If the uplink is 100 Mbps, then the maximum number of IP trunk
cards allowed on the switchis subject to the limits described in "Calculate
Ethernet and WAN bandwidth usage" (page 111).
Consider implementing LAN resiliency. This can involve installing redundant
up-links, backup routers and an Uninterruptible PowerSource (UPS).
ATTENTION
IMPORTANT!
Shared media hubs are not supported. Use Layer 2 switches.
Place the IP Trunk3.01 (and later) node and the TLAN subnet router as
close to the WAN backboneas possible. This enables the following:
•minimizes the number of router hops
•segregates constant bit-rate voice traffic from burstyLAN traffic
•simplifies the end-to-end QoS engineering for packet delay,jitter, and
packet loss
If an access router separates the IP Trunk 3.01 (and later) node from the
WAN router, there should be a high-speed link, such as Fast Ethernet,
FDDI, SONET,OC-3c, ATM STS-3c, between the access router and the
WAN backbone router.
Configure the TLAN subnet IP router
The IP Trunk3.01 (and later) node must be placed on its own TLAN subnet.
The router should have a separate 10/100BaseT interface for the TLAN
subnet and should not contain any other traffic. Other IP devices should
not be placed on the TLAN subnet.
Nortel Communication Server 1000
IP TrunkFundamentals
NN43001-563 02.01 Standard
Release 5.5 21 December 2007
Copyright© 2007, Nor tel Networks
.