Understanding the network.pdf - Back to Home

• Link and services monitoring, network performance baselining, and periodic
performance revaluation. Proactive and reactive hardware, link and network
service failure detection. Network security monitoring.
In small office networks (generally 20 to 50 nodes), these duties are often
performed by a solitary network administrator. In this kind of scenario, spreadsheet
record-keeping or station and topology mapping with graphics packages like
SysDraw or VISIO is possible, because one person will always be able to find and
control the documentation. Router and other device configurations can be saved to
a TFTP server. Link and service monitoring, if they are done at all, are accomplished
with custom checking scripts, or with a free or commercial monitoring package and
an email-enabled pager.
In large enterprises, a network environment that consists of hundreds or thousands
of nodes, some kind of Network Management System (NMS) is generally required.
These systems are either maintained by the IT or MIS department, or outsourced to
network management firms like Electronic Data Systems (EDS). In either case,
large-scale NMSs are expensive and complicated. They require expensive hardware
and software components and, most importantly, trained staff to interpret the
management data and do problem resolution. No matter how great your
management system is, it cannot interpret the data it collects or fix your network
when it goes down. That must be done by the network administration staff.
When determining your network's management system requirements, it is essential
that you define what the NMS's operational scope will be. Without defining what
your network management needs are, you can easily spend too much time and
money developing a system that can perform many functions that you will not need.
For example, the use of custom monitoring scripts using ping is a perfectly
acceptable method for verifying if an IP-based device is up on the network. Ping
might not tell you if it is operating correctly, but it will verify that it is online. This
solution, for most scenarios, is adequate. If the script fails, it can send you email
notification of the failure. Alternatively, you can spend some significant money on a
management system that will poll the device and verify that all of the services are
functioning correctly, and attempt to restart it if it's not. When restart fails, the
system will notify you with an email. The point is that you need to determine what
your network's operational and service requirements are and then use a network
management approach that will accommodate those requirements in a sane,
cost-effective manner.
The broad scope of activities that fall under network management often become
blurred together. Network management system developers have a tendency to
promise much more than they can deliver—easy configuration, automatic data
collection, problem resolution, and so on. Effective network management is not
easy; in fact, it can be downright tedious and frustrating at times. NMSs are only a
tool, a very helpful tool when implemented correctly. They are not the only tool