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Chapter 1

The Campus Network

The New 20/80 Rule

With new Web-based applications and computing, any PC can be a sub-
scriber or publisher at any time. Also, because businesses are pulling servers
from remote locations and creating server farms (sounds like a mainframe,
doesn't it?) to centralize network services for security, reduced cost, and
administration, the old 80/20 rule is obsolete and could not possibly work in
this environment. All traffic must now traverse the campus backbone, which
means we now have a

20/80 rule

in effect. Twenty percent of what the user

performs on the network is local, whereas up to 80 percent crosses the net-
work segmentation points to get to network services. Figure 1.2 shows the
new 20/80 rule network.

F I G U R E 1 . 2

A 20/80 network

The problem with the 20/80 rule is not the network wiring and topology

as much as it is the routers themselves. They must be able to handle an enor-
mous amount of packets quickly and efficiently at wire speed. This is prob-
ably where we should be talking about how great Cisco routers are and how

VLAN3

VLAN2

VLAN1

VLAN4

VLAN5

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