Estimate Network Loading Caused By Ip Trunk 3.01 (And Later) Traffic - Nortel 1000 Description, Installation And Operation Manual

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Estimate network loading caused by IP Trunk 3.01 (and later)
traffic
553-3001-363 Standard 2.00
ITG engineering guidelines
The third step is to assess how much spare capacity is available. Enterprise
intranets are subject to capacity planning policies that ensure capacity use
remains below some determined utilization level. For example, a planning
policy might state that the utilization of a 56 kbit/s link during the peak hour
must not exceed 50%; for a T1 link, the threshold is higher, for instance, 80%.
The carrying capacity of the 56 kbit/s link would be 28 kbit/s and for the T1,
1.2288 Mbit/s. In some organizations the thresholds can be lower than those
used in this example; in the event of link failures, there must be spare capacity
to re-route traffic.
Some WAN links can be provisioned on top of Layer 2 services such as
Frame Relay and ATM; the router-to-router link is actually a virtual circuit,
which is subject not only to a physical capacity, but also to a "logical
capacity" limit. Obtain, in addition to the physical link capacity, the QoS
parameters, especially the Committed Information Rate (CIR) for Frame
Relay and Maximum Cell Rate (MCR) for ATM.
The difference between the current capacity and its allowable limit is the
available capacity. For example, a T1 link utilized at 48% during the peak
hour, with a planning limit of 80%, had an available capacity of
approximately 492 kbit/s.
At this point, enough information has been obtained to "load" the IP Trunk
3.01 (and later) traffic on the intranet. Figure 25 on
this is done on an individual link.
September 2004
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