Now that the end-system network configuration table is complete, we will focus on the end-system
network topology diagram. Like the topology diagram for the network, the end-system diagram is
designed to give a graphical representation of the end-systems in the network, giving you a better
view of traffic flow and interdependencies. This view also allows for easier identification of potential
bottlenecks or significant points of failure. For example, you can easily see on the end-system network
topology diagram whether your users will need to cross a slow serial connection to get to new
servers that are being put in. You can also see if there is only one path available from these users to
the servers, and, if redundancy is required, alter the location of the servers or add another path.
In most cases, the end-system network topology diagram is just an extension of the network
topology diagram, with the information gathered for the end-system network configuration
table added. Because of the amount of information included in these diagrams, it is necessary
to ensure that only pertinent data is added. Adding too much data can quickly clutter up the diagram
and make it difficult to use.
Typical items in an end-system topology diagram are as follows:
System Name
Connection to the Network
System Purpose
VLAN
IP Address
Subnet Mask
Network Applications
At a minimum, the system name and connection to the network are needed on the topology
diagram. The exception to this rule is when you are including a large number of like-configured
end systems that serve a common purpose and exist on the same subnet. In this arrangement,
where it is impractical to include each separate machine in the diagram, they can be grouped
together and represented by descriptive text. An example of this grouping is shown in Figure 35.2
in the next section.
Windows Name Resolution
When working with Windows systems, it is important to know the process by which names are
associated to IP addresses. In a Unix system, this resolution is relatively straightforward and usually
involves the use of cached entries, a HOSTS file, or DNS. In a Windows environment, however,
there are a few other options available. All the options that are available are as follows:
Internal cache of recently used entries
Broadcast message to the local network
Local LMHOSTS file
Local HOSTS file
WINS server
DNS server
In addition to the local cache, the HOSTS file, and DNS are three other options: broadcast, LMHOSTS,
and WINS. The order in which these items are checked in a Windows system varies based on a
number of factors, but in general, the internal cache and broadcast message are the first items
used to try to resolve a name into an IP address.
Following this, the LMHOSTS and HOSTS files are used. Both these files are usually located in the
%SystemRoot%\System32\Drivers\Etc directory of each Windows end system. They are textbased
files that can be edited to provide static name-to-IP-address translation.
Next in the series is the Windows Internet Name Service (WINS) server, which is Microsoft’s
version of a NetBIOS name server. It dynamically updates the names of other Windows clients
that are on the network. The server can then be queried in much the same manner as a DNS
server for name-to-IP-address resolution.
The final item used by a Windows end system is a DNS server. As is the case with any station
using DNS, a Windows station sends a query to the DNS server, and the server responds with
the IP address or a notification saying it does not know the address.