Increasing Bandwidth

In addition to creating additional segments to
increase available bandwidth, you can use a faster
medium such as optical fiber or Gigabit Ethernet.
Although these technologies are faster, they are still
shared media, so collision domains will still exist
and will eventually experience the same problems
as slower media.

Increasing Bandwidth

In addition to creating additional segments to
increase available bandwidth, you can use a faster
medium such as optical fiber or Gigabit Ethernet.
Although these technologies are faster, they are still
shared media, so collision domains will still exist
and will eventually experience the same problems
as slower media.

Increasing Bandwidth

In addition to creating additional segments to
increase available bandwidth, you can use a faster
medium such as optical fiber or Gigabit Ethernet.
Although these technologies are faster, they are still
shared media, so collision domains will still exist
and will eventually experience the same problems
as slower media.

Smaller Segments

Segments can be divided to reduce the number of
users and increase the bandwidth available to each
user in the segment. Each new segment created
results in a new collision domain. Traffic from one
segment or collision domain does not interfere with
other segments, thereby increasing the available
bandwidth of each segment. In the following figure,
each segment has greater bandwidth, but all segments
are still on a common backbone and must
share the available bandwidth. This approach works
best when care is taken to make sure that the largest
users of bandwidth are placed in separate segments.
There are a few basic methods for segmenting an
Ethernet LAN into more collision domains:
• Use bridges to split collision domains.
• Use switches to provide dedicated domains to
each host.
• Use routers to route traffic between domains
(and to not route traffic that does not matter to
the other domain).
This sheet discusses segmenting using bridges and
routers (switching is covered in the next chapter). 53

Ethernet Collisions

In a traditional LAN, several users would all share
the same port on a network device and would
compete for resources (bandwidth). The main limitation
of such a setup is that only one device can
transmit at a time. Segments that share resources
in this manner are called collision domains,
because if two or more devices transmit at the
same time, the information “collides,” and both
end points must resend their information (at different
times). Typically the devices both wait a random
amount of time before attempting to retransmit.
This method works well for a small number of
users on a segment, each having relatively low
bandwidth requirements. As the number of users
increases, the efficiency of collision domains
decreases sharply, to the point where overhead traffic
(management and control) clogs the network.