SURVIVABILITY--WHERE NETWORK MANAGEMENT REALLY PAYS
Of course there is a fine line defining network capacity. If too much capacity exists,
there will probably be few user complaints, but there is excess capacity. Excess capacity
implies wasted resources and, thus, wasted money. Excess capacity, of course, can accom-
modate short-term growth. Therefore, performance/growth management supplies vital
information on network utilization. Such data provide the groundwork for future planning.
Security management controls access to and protects both the network and the network
management subsystem against intentional or accidental abuse, unauthorized access, and
communication loss. It involves link encryption, changes in encryption keys, user authen-
tication, passwords, firewalls, and unauthorized usage of telecommunication resources.
Accounting management processes and records service and utilization information. It
generates customer billing reports for services rendered. It identifies costs and establishes
charges for the use of services and resources in the network. It may also be a repository
for plant-in-place investment for telecommunications plant and provides reports to upper
management on return on that investment.
SURVIVABILITY -- WHERE NETWORK MANAGEMENT REALLY PAYS
The network management center is the front-line command post for the battle for network
survivability. We can model numerous catastrophic events affecting a telecommunications
network, whether the PSTN or a private/enterprise network. Among such events are fires,
earthquakes, floods, hurricanes, terrorism, and public disorder. Telecommunications have
brought revolutionary efficiencies to the way we do business and is so very necessary
even for life itself. Loss of these facilities could destroy a business, even possibly destroy
a nation. A properly designed network management system could mitigate losses, even
save a network almost in its entirety.
Cite the World Trade Center explosion (first attack) in New York City. The entire
PABX telephone system survived, less the extensions in the immediate area of the bomb,
simply because the PABX was mounted on the 6th floor. All offices in the building had
communications within the building and with the outside world. The vital communications
were never lost.
This brings in the first rule toward survivability. A network management center is a
place of point failure. Here we mean that if the center is lost, probably nearly all means
of reconfiguring the network are lost. To avoid such a situation, a second network man-
agement center should be installed. This second center should be geographically separate
from the principal center. It is advisable that the second center share the network manage-
ment load and be planned and sized to be able to take the entire load with the loss of the
principal center. There should be a communications orderwire between the two centers.
Both centers should be provided with no-break power and backup diesel generators.
One simple expedient for survivability is to back up circuits with an arrangement with
the local telephone company. This means that there must be compatibility between the
enterprise network and the PSTN as well as one or more points of interface. A major
concern is the network clock. One easy solution is to have the enterprise network derive
its clock from the digital PSTN. The local enterprise network should also be provided a
backup clock in case effective timing is lost from the PSTN.