CHAPTER ONE
INTRODUCTION
1.1 BACKGROUND
The entire Ahmadu Bello University Campus Network Infrastructure, runs on fiber optic
technology for transmission and is built based on the Cisco standard hierarchical design standard
for campus networks (core, distribution and access levels) providing high speed and redundancy.
The network is built on Cisco technology using high end devices which include Cisco Catalyst
6500 series as the core switch, 4500, 3700 and 3560 series switches as distribution switches and
2960 series and gigabit small business series switches as access switches. This setup guarantees
gigabit transmission to every host on the network. The network covers all the campuses of ABU
Zaria which include Samaru, Kongo, Shika and NAPRI all connected with over 60km of optical
fiber cable.
The core network as in Figure1.1 is built on the Virtual Switching System technology for high
capacity using ether channel technology, whereby so many fiber ports are bundled together for
more bandwidth capacity on a link, all the servers are part of the core network including the
authentication server. Distribution is built on Layer 3 switches the Cisco 3750G all the distribution
points are connected back to the core network through a fiber link, with static addressing of point
to point nodes. Dynamic routing protocol is enabled running Open Shortest Path First (OSPF),
with each distribution switch used as the OSPF Area Border Router (ABR) with separate areas.
The distributions also host the virtual local area network VLAN of each access layer switches.
The access layer which comprises mainly of Small Business Series switches and 2960 series
switches is built on Layer 2 switching technology. Access layer devices have access to Dynamic
Host Configuration Protocol (DHCP) services from the distribution switch to which the Access
switch is connected.