Foundation Summary 61
Table 2-3
Hubs, Bridges, Switches, and Routers
Device
Does it Segment
Bandwidth Domain?
Does it Segment
Broadcast
Domain?
Standard Usage
OSI Model
Hub
No
No
Connects devices in
small LANs
Physical layer
Bridge
Yes
No
Connects networks
Data link layer
Switch
Yes
No
Connects individual
devices or networks
Data link layer
Router
Yes
Yes
Connects networks
Network layer
Table 2-4
Network Performance Parameters
Function
Goal
Performance
Measure and make available various aspects of network performance so that
internetwork performance can be maintained at an acceptable level.
Configuration
Monitor network and system configuration information so that the effects on
network operation of various versions of hardware and software elements can be
tracked and managed.
Accounting
Measure network-utilization parameters that the individual or group uses so that the
network can be properly regulated. Regulation minimizes network problems and
maximizes the fairness of network access across all users.
Fault
Detect, log, notify users of, and, where possible, automatically fix network
problems to keep the network running effectively. Fault management is perhaps the
most widely implemented of the ISO network management elements.
Security
Control access to network resources according to company guidelines so that the
network cannot be sabotaged (intentionally or unintentionally) and sensitive
information cannot be accessed by those without appropriate authorization.
87200333.book Page 61 Wednesday, August 22, 2001 2:18 PM