Networks

There are two types of network.

• LAN &
• WAN

Routers connect the two. They are configured to pass and accept messages to and from legitimate WAN addresses. Firewalls can be used, too.

Four types of architecture

• Bus
• Ring
• Star
• Tree

Network risks include

• Wiretapping or copper of fibre optic cables
• Sniffer programs
• Wireless leakage

Separate domains can be used, but network management is a critical and highly skilled role.

The internet itself is a WAN. It was developed as a means for academic to share files, so it was not developed with security in mind. Messages are broken up into packets for transmission and are reconverted into messages at the target computer. The coding and decoding is done by TCP (transaction control protocol). Major uses of the internet for communication are email and ecommerce.

Network Management

Network management governs connections between hardware, applications, LANs, WANs and the internet. Responsibilities include

• Planning & design
• Change management
• Troubleshooting
• Maintenance
• Performance
• Capacity/availability management
• Configuring, control and optimisation of networked resources

Network planning is closely aligned to IT strategy.

Capacity Management

The purpose of these activities is to determine how information technology demands will increase and over what timescale.

In essence capacity management is made up of three sub processes:

• Business capacity management (BCM) – to forecast capacity needs based on business events
• Service capacity management (SCM) – to ensure capacity levels support established service level targets
• Resource capacity management (RCM)

 Inputs

• Performance and workload monitoring
• Application sizing
• Resource forecasting
• Demand forecasting and
• Modelling

Outputs
 

• Forecasts
• Capacity plan
• Tuning data and
• Service level management guidelines

Possible KPIs related to efficiency and effective capacity management

• total cost of unplanned capacity expenditures
• total cost of unused capacity
• accuracy of capacity forecasts
• number of incidents related to capacity/performance issues
• number of service level agreement performance targets missed due to capacity.

ISO 2000 on service management covers this area.

Processing & Connectivity

Hardware and software together are known as system architecture.

Within infrastructure, we consider the IT roles within a centralised IT department, distributed computing, distributed and local computing and change control.

We consider network.