10
Chapter 1
The Campus Network
The New Campus Model
T
he changes in customer network requirements--in combination with
the problems with collision, bandwidth, and broadcasts--have necessitated
a new network campus design. Higher user demands and complex applica-
tions force the network designers to think more about traffic patterns instead
of solving a typical isolated department issue. We can no longer just think
about creating subnets and putting different departments into each subnet.
We need to create a network that makes everyone capable of reaching all net-
work services easily. Server farms, where all enterprise servers are located in
one physical location, really take a toll on the existing network infrastruc-
ture and make the way we used to design networks obsolete. We must pay
attention to traffic patterns and how to solve bandwidth issues. This can be
accomplished with higher-end routing and switching techniques.
Because of the new bandwidth-intensive applications, video and audio to
the desktop, as well as more and more work being performed on the Internet, the
new campus model must be able to perform the following:
Fast Convergence
When a network change takes place, the network
must be able to adapt very quickly to new changes and keep data moving
quickly.
Deterministic paths
Users must be able to gain access to a certain area of
the network without fail.
Deterministic failover
The network design must have provisions that
make sure the network stays up and running even if a link fails.
Scalable size and throughput
As users and new devices are added to the
network, the network infrastructure must be able to handle the new
increase in traffic.
Centralized applications
Enterprise applications accessed by all users
must be available to support all users on the internetwork.
The new 20/80 rule
Instead of 80 percent of the users' traffic staying on
the local network, 80 percent of the traffic will now cross the backbone
and only 20 percent will stay on the local network.
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