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Chapter 4. Media Access Continued
Generally, we have two types of networks – regardless of the topology.
A) Peer-to-Peer Network; in this fashion, there is no dedicated server. Workstations are connected
to each other without a centralized server to manage services. Say you share a printer between
multiple work stations in BUS topology. Recall that in Peer-to-Peer the maximum number of
nodes which can be connected is (Node = any device with an IP) ten. Each computer is a client
and a server, but they are very ‘active’ clients and ‘passive’ servers.
B) Client/Server Network. The server is the centralized manager and can have an unlimited
number of clients. So, at the heart of this system there is a dedicated server. The server uses
special operating systems: Windows 2003, 2008, Unix, Linux(?). The dedicated server is running
a NOS (Network Operating System). The server controls access to network resources. Note:
Client/Server Network requires an existing network infrastructure (topology).
Though we have numerous topologies, the most popular topology today is: …
Regarding the Ethernet,
Supports Star/BUS (IEEE 802.3), Star Support CAT 3,4,5,5a,5e (although CAT 3 and 4 are not star)
– Cat5: Shielded Twisted Pair OR Unshielded Twisted Pair *Note: Cat 3 is a Token Ring 16 M/S
Network, Cat 4 is another version of Token Ring.
Cat5 is either a shielded twisted pair (very expensive) or unshielded twisted pair (UDP)(RJ45
connection). Max length 100m. CAT5 supports 10/100 Base-T [IEEE notation](twisted pair). *Note:
100Base = TX.
Cat5a,e supports: 1000Base-T (Speed: 1 G/S or 1000 M/S) <- Ethernet topology
Cat6a supports: 10GBase-T (Max Cable Length: 100m)
Multiple Access Unit (MAU) Token Ring is a “hub”. Recall that a star network topology is using a
hub or a switch. It can use CAT cables to connect to clients.
Sometimes we need more speed, so we need fiber optic cables. The first fiber optic network was
called FDDI. FDDI was designed based on the token ring topology, with the following features:
a) Introduction to Dual Ring
b) Extended the distance limitation of CAT3 (100 m) to 1000m using fiber optic cables
Fiber optic cable comes in two versions or types.
a) Single-mode Cable: Capable of extending the cable length up to 40 km (although we
have 100 and 400 km types). It carries one type of signal only, in other words, it is
Baseband. Uses ‘pure’ fiber glass. It will break if bent.
b) Multi-mode: Supports multiple signals. Supports shorter distances than single-
mode. And uses a mix of fiber glass and plastic material