Nortel 1000 Fundamentals page 112

112 ITG engineering guidelines
To calculate the bandwidth requirement of a route, divide the total route
traffic by 36 CCS and multiply by the bandwidth use. All traffic data must be
based on the busy hour of the busy day.
To calculate resource requirements (IP Trunk 3.01 (and later) ports and
TLAN subnet/WAN bandwidth), traffic parcels are summarized in different
ways:
1. Add all sources of traffic for the IP Trunk 3.01 (and later) network,
2. For data rate requirement at each route, the calculation is based on
3. For fax traffic on a WAN, only the larger of either the fax-sent or
The engineering procedures for the TLAN subnet and WAN are different.
The following calculation procedure is for the TLAN subnet. The modification
required for WAN engineering is included in these procedures.
IMPORTANT
Voice packets must have priority over data packets.
When the WAN route prioritizes voice traffic over data traffic, the route bandwidth
can be engineered to 90% loading level; otherwise, a WAN route with bandwidth
of 1.536 Mbit/s or more can only be loaded up to 80%. A smaller WAN pipe (64
kbit/s) is recommended to a loading of 50%.
In Table 17 "Silence Suppression disabled TLAN Ethernet and WAN IP
bandwidth usage per IP Trunk 3.01 (and later) " (page
bandwidth is without Frame Relay or ATM overhead.
The Frame Relay overhead is 8 bytes (over IP packet).
The LLC SNAP (Link Layer Control SubNetwork Attachment Point) and
AAL5 overhead for ATM is 16 bytes (over IP packet).
IP packet size over 53 bytes requires two ATM cells, over 106 bytes requires
three ATM cells, and so on. Within the same number of cells, the bandwidth
requirements are the same for packets with different sizes.
TM 3.1 input for fax is in bytes, ranging from 20 to 48;
30 bytes is the default.This differs from voice applications where payload
size is the input.
Copyright © 2007, Nortel Networks
.
such as voice, faxes sent, and faxes received, together to calculate IP
Trunk 3.01 (and later) port requirements and TLAN subnet bandwidth
requirements.
each destination pair.
fax-received traffic is to be accounted for.
Nortel Communication Server 1000
IP Trunk Fundamentals
NN43001-563 02.01 Standard
Release 5.5 21 December 2007
ATTENTION
113), the first WAN