User's Manual

682 CHAPTER 17: USING 3COM NETWORK DIRECTOR ON A MULTI-SITE NETWORK
physically located, or the PC that runs an application is located, is known
as the local site. Other sites are known as remote sites.
Similarly, devices that are located at the local site are known as local
devices, while devices that are located at remote sites are known as
remote devices.
Issues with Managing a Multi-Site Network
Due to their differences, managing a multi-site network is not as
straightforward as managing a network whose components are restricted
to a single site. These differences result in several issues specific to
managing multi-site networks, some of which are:
■ The geographical separation of the sites means that device failure,
physical network changes and, in some cases, device reconfigurations
require either site visits or a network manager at each site to resolve
them.
■ The links between sites, WAN links, are generally slower than the links
within sites, LAN links. These cause larger latency between sites that
is normally seen within a single site. This may cause problems with
time-sensitive data, such as VoIP traffic.
■ Due to their monetary cost, WAN links are often utilized at near to
their full capacity. Additional traffic directed to such WAN links can
result in the links becoming less reliable than normal, with the routers
at either end dropping some of the packets destined for the link. This
can potentially disrupt the performance of the applications in your
network that run across multiple sites.
■ The links between sites may be installed, owned and managed by a
service provider, leaving you with little or no control over them.
3Com Network
Director
Support for
Multi-Site Networks
3Com Network Director monitors and manages the devices in your
network from a single PC. As a result, when running in a multi-site
network there are some issues that can arise with the default
configuration of 3Com Network Director:
■ Due to the additional latency caused by WAN links, discovery of
remote sites may take much longer than the discovery of the local site.
■ One of the attributes that 3Com Network Director uses to monitor the
status of devices in your network is their responsiveness (this is shown
by the IP Ping Service monitor). When monitoring remote devices the
additional latency caused by the WAN links may result in these devices