Assessing Wan Link Resources - Nortel Remote Office 9150 Installation And Administration Manual

Network engineering guidelines

Assessing WAN link resources

Introduction
For most installations, Remote Office traffic is routed over WAN links within the
intranet. WAN links are the most expensive repeating expenses in the network,
and they often are the source of capacity problems in the network. Unlike LAN
bandwidth, which is virtually free and easily implemented, WAN links,
especially inter-LATA and international links, take time to obtain financial
approval, provision, and upgrade. For these reasons, it is important to determine
the state of WAN links in the intranet before installing the Remote Office
network.
Each voice conversation (G.729 Annex AB codec, 30 ms payload) consumes
11.2 Kbps of bandwidth or 18.6 Kbps for each link that it traverses in the
intranet. A DS0 64 Kbps WAN link supports five simultaneous telephone
conversations.
Determining the state of WAN links
1 Obtain a current topology map and link utilization report of the intranet.
A visual inspection of the topology map should reveal which WAN links are
likely to be used to deliver Remote Office traffic.
Note: For an example, see the network topology map on page 387.
Alternatively, use the traceroute tool. See "Measuring the intranet Quality of
Service" on page 403.
386
Standard 1.0
Remote Office 9150