- 1. Lecture 8 Network Installation, Performance and
Management
2. Topics
3. Network Installation
- When putting together costs for installation of a network,
there are many hidden costs to be allowed for.
- The reasons for this relate primarily to the need to minimize
disruption both now and in the future.
- Networks should be cabled with sufficient capacity for the
future both in terms of traffic as well as connected ports,
accessible pull boxes, etc. and should have all networking devices
accessible to allow for quick replacement should any device
fail.
- Depending on the nature of the business and the network,
disruption to the network could cost the company millions of
pounds.
4. Types of Network Wiring
- Natural this is the natural structure which has evolved over a
period of time. Likely to include legacy cabling from previous
networking layouts. Generally arises as the network expands in an
ad hoc manner to meet the companies changing needs.
5. Types of Network Wiring
- Standardized This arose through attempts to standardize the
cabling on a particular technology. In order to solve the problems
associated with natural wiring, they would run one high capacity
system everywhere (often coax cable based) in an attempt to give
suitable performance to all locations.
- Unfortunately as demand continued to rise, yet more cabling was
required often requiring a completely different wiring topology and
perhaps of a different cable type from that already installed.
6. Types of Network Wiring
- Structured The next solution basically breaks the problem into
parts and cables accordingly.
- Sockets (typically RJ45) are sited close to the
users/printers/telephones and wired back using individual 8 core
cables to patch panels in a wiring closet where there are Ethernet
hubs, switches, token ring MAUs or telephone voice panels.
- These patch panels then link together the various systems
within the area to form an overall integrated computer networking
and telecom system. These are then linked back to a central
area.
- Currently, the structured approach is the preferred choice and
is used extensively through the University.
7. Structured Cabling
- Using the structured cabling approach, it is relatively easy to
change network topologies. Relocation of users, peripherals and
telephones are also much easier.
- It is common practice nowadays to floodwire buildings to
minimise the need for additional cabling at a later stage. Often
six ports will be wired for each likely user of the system to
provide some level of expansion within the system. Typically a user
will utilize three ports (computer, printer and telephone).
8. Planning a Network
- The first step in all but the smallest of networks is to plan
the installation. This generally will start with Capacity Planning
to determine cabling types and necessary equipment.
- You must check for sources of noise which may interfere with
the system.
- In larger installations, you should be aware of the expected
growth/decline of the company, new business areas and practices and
likely staff movements.
- Consider flood wiring with a high wiring ratio (perhaps 8:1 or
10:1) without necessarily fitting all sockets and equipment,
etc.
9. Design Considerations 10. Design Considerations 11. Design
Considerations 12. Design Considerations 13. Design Considerations
14. Self vs Contractor Installation
- Unless you are in the business of cabling, it is likely to be
more economical and beneficial to contract this to a specialist.
Cabling often involves holes to be cut in the building
infra-structure requiring a suitable knowledge of structural
issues.
- The installation must meet all the requirements of the Health
and Safety regulations
- It is not recommended that you undertake an installation
requiring structural alteration to a building without the help of
suitably qualified specialists neither will your insurance
company.
15. Self vs Contractor Installation
- Care must be taken when connecting buildings in close
proximity. Cables may need to be raised to high levels to allow
high vehicles to pass underneath. However cables elevated to this
height face other dangers, such as interference with power lines
and lightning strikes.
- Also if supply to the neighbouring building is from a different
source, ground currents between the two systems are potentially
lethal.
- Use of fibre optic cable is now essentially standardised.
16. Cabling Types
- Structured Cabling normally uses either Unsheilded Twisted Pair
(UTP) or Shielded Twisted Pair (STP)
- UTP normally comes in three grades
- CAT-3 (three twists/metre)
- CAT-4 (four twists/metre)
- CAT-5 (five twists/meter)
- The higher the twists/meter, the better the screening factor
and higher the price.
17. Post Installation
- After completion of the network cabling and before it goes
live, several procedures should be adopted.
- Measure cable drops to equipment and document results.
- Fully document the network and draw plans noting any IP numbers
on the plans.
- Baseline the network performance with specialist testing
software (such as Sniffer)
- This process will help identify faults as they arise in the
future.
18. Network Management
- In order to ensure the network remains in good condition it is
important that this be effectively managed.
- Network Management falls into two main categories, namely
- It is effective management of these two key factors that keep a
network in good shape performing close to its theoretical
performance.
19. Network User Issues
- Maintenance of User accounts creating users, passwords managing
network disk space, freeing up of locked-up accounts.
- Security issues associated with a large number of users,
creation of group accounts to permit groups to work freely with
each other etc.
- The object of User maintenance is to try to keep the network at
all times available and accessible without compromise on security
issues.
- Preparation and activation of contingency plans should the
network be unavailable.
20. Network Technical Issues
- Technical issues divide into three distinct areas
- Back-up maintenanceis in many ways the most critical. In case
of disaster or accidental deletion, data can be retrieved.
- Backups must be taken at regular intervals based on a corporate
decision of what data interval you are prepared to loose. If the
interval is too long, then either more frequent backups must be
taken or consider investment be made in RAID technology.
21. Network Technical Issues
- Software Maintenancerequires the networking of various software
applications, including upgrades and patches to be applied, audit
trails protecting and printing.
- Also includes the maintenance of of network devices, resetting
print queues, maintenance of print servers, etc.
- Management of interconnection devices (bridges, repeaters,
gateways, etc.) using management tools utilizing, for example,
Simple Network Management Protocol (SNMP).
22. Network Technical Issues
- Performance Maintenance Probably the most contentious of all
issues. Once a network is installed or upgraded, the demand for its
services is likely to increase. Also as users become more
competent, information will be accessed more frequently putting
even more traffic through the system.
- Knowledge of which protocol to use and the appreciation of the
effects at high data rates are essential when designing a system to
ensure that system performance is maintained. It is not just
capacity that is important but also the system throughput.
23. Network Technical Issues
- Reliability and Availability . One Hundred percent reliability
is not possible but companies must be prepared to accept costs of
installing extra cabling and equipment as a contingency.
- Equipment purchased should have high MTBF (mean time between
failures) rating as well as low MTTR (mean time to repair).
- Designers should also choose products from reliable
manufacturers who can be obtained quickly in the event of a
failure. Also the availability of technical support from the vendor
can also be important.
24. JANET Backbone & NorMAN
- Check out JANET BackBone document on download page
- NorMAN North East Metropolitan Area Network
- Sunderland University Network Design
25. 26. The End