part of the domain to determine the scope of the
end-system network documentation. Only collect data
that is relevant to the objective and provide sufficient detail
for those relative pieces. Extra layers of information will
only make the documentation more difficult to use.
Use consistent terminology, abbreviations, and style.
Make the documents orderly and easy to understand.
Use templates and keep a library of symbols and
graphic icons that can be reused. Store the network
documentation in a location where it is readily available on
the job. A copy of the documentation should also be kept in a
secure off-site location. Modify the network
documentation as conditions and devices in the network change.
A standardized process should be implemented for
handling changes to network documentation. Factors in this
process that need to be accounted for include reporting network
changes, maintaining version control and assigning
responsibility for modifying and distributing updated
documents. Example
Last year documentation of the
network for a branch of the corporation was completed. One year
later, troubleshooters still use the network documentation to
successfully troubleshoot network problems. The following is a
list of reasons that the documentation process was successful:
- Network segments and devices were identified within
the domain of responsibility.
- The purpose for creating
the documentation was determined.
- The most
experienced network employees were queried to learn about what
information would be the most useful to meet their needs.
- Consistent symbols and terminology were used to
represent the data in both graphical and tabular form.
- Logical locations were designated to store copies of the
documentation and indexing permitted networking personnel to
easily find the needed data. A sign-out sheet was implemented
so that possession of copies of the network documentation could
be accounted for.
- A reporting system was instituted
so employees could relay information about changing conditions
in the network to a central location. When a change in network
conditions took place, employees knew whom to notify and that
person promptly modified, dated, and distributed the updated
documentation to the designated locations.
Lab
Activity Lab Exercise: Network Baseline Discovery In this
lab, the student will establish the baseline for the
configuration and operation of the student network.
Content 1.3 Building-Block Approach
1.3.1 Identifying the components of an end-system
configuration table Network documentation can be a valuable
tool for troubleshooting. However, a network is not complete
without end-systems. An incorrectly configured end-system can
have a negative impact on the overall performance of a network.
This section discusses the creation of configuration
documentation for the purposes of troubleshooting end-systems
connected to a network. The information contained in this
section assumes a scenario where network devices have already
been documented but the network administrator is unfamiliar
with the configuration. Therefore the end-system portion of the
network documentation will need to be created from scratch.
End-system devices such as servers, network management
consoles, and desktop workstations play a large role in the way
a network operates and, therefore, should not be ignored.
Maintaining relevant documentation about the configuration of
end-systems provides a complete picture of the network and
allows intelligent decisions about any modifications or
upgrades that end-systems may require. The inclusion of
end-system network configuration information in the baseline
will enable troubleshooting of problems in a timely and
efficient manner. An end-system network configuration table is
baseline documentation that shows accurate records of the
hardware and software used in end-systems. When creating an
end-system network configuration table for troubleshooting, the
following should be documented: - Device Name (Purpose)
- Operating System/Version
- IP Address
- Subnet Mask
- Default Gateway, DNS Server, and WINS
Server Addresses
- Any High-Bandwidth Network
Applications that the End-System Runs
An end-system
network configuration table will contain different components
based on its use. Some tables are used administratively for
inventory. Some simply list the physical location of the device
and perhaps a note about when it needs to be backed up, while
others are used as a tool for troubleshooting. An end-system
network configuration table used for troubleshooting typically
varies, depending on the device being recorded. There are many
different types of end-systems and, therefore, there is quite a
bit of information that can be recorded. To simplify things, it
can be helpful to divide the recorded information into
categories based on the relationship the component has with the
layers of the TCP/IP model. It is important to find out what
the most useful pieces of information are for troubleshooting
particular end-systems. Recording network applications that are
available on an end-system is also useful information to
include on an end-system network configuration table.
Additionally, record any high-bandwidth network applications
that are running on the end-system, because they can have a
large impact on network performance. Examples of high-bandwidth
applications are streaming video, such as QuickTime, and
multicast applications, such as IP/TV. Figure provides an
example of an end-system configuration table using the
following categories to document the network-related properties
of a device: - Device Name (Purpose)
- Operating
System/Version
- IP Address/Subnet Mask
- Default Gateway Address
- DNS Server Address
- WINS Server Address
- Network Applications
- High-Bandwidth Applications
Content
1.3 Building-Block Approach
1.3.2 Identifying the components of an end-system
topology table An end-system network topology is a
graphical representation of the tabular data gathered in the
end-system network configuration table. Topologies should
illustrate how end-systems are both physically and logically
connected to the network. Since end-systems are frequently
added to existing network diagrams, topology diagrams that
include end-systems often include components of network device
configurations. Like the network devices in a topology diagram,
end-systems in a network topology do not typically include
every component of the end-system network configuration table.
Minimally, the end-systems on a topology diagram should include
the name, an illustration of the device and how it is connected
to the network. Like an end-system network configuration table,
the components of a topology diagram that includes end-systems
can have different components, depending on the types of
end-systems in the network. These components can also be
categorized according to logical TCP/IP layers. A topology
diagram that includes end-systems will differ, depending on its
focus. A topology that is focused on the end-systems rather
than the configuration of network devices may represent the
network components as a network cloud symbol with the details
of the end-systems connected to it. On the other hand, all the
details of the network device configuration may be included on
the same diagram as the end-systems. Figure provides an example
including the following components related to end-systems:
- Device name and purpose
- Operating system
- IP address
Content
1.3 Building-Block Approach
1.3.3 Identifying commands and applications used to
discover information about end-system configuration Figure
shows general commands that a troubleshooter uses to gather
information about the network configuration of an end-system.