Network architecture is something that came about one day when someone sat down and said “We are going to design a network architecture; let’s use CAT 3 cabling, a star topology, and CSMA /CD as an access method. Let’s call this architecture 10BaseT” In this example, 10BaseT was the name assigned to the architecture because 10 Mbps is the transfer rate of the network, Baseband communication is the technique used to transmit the signal, and the T means our cable type —in this case twisted pair. We know different types of twisted-pair cabling, but CAT 3 is the one that runs at 10 Mbps, so it is the cable used in 10BaseT.
The first types of network architecture to look at are the different Ethernet architectures. When designing networks, one of the first decisions we usually make is “Do we want to use Ethernet or the competing network architecture called Token Ring? we want to use Ethernet. What flavor of Ethernet?” In this discussion you will understand what the different flavors of Ethernet are. Ethernet is defined as the IEEE 802.3 standard.
10Base2
The 10Base2 Ethernet architecture is a network that runs at 10 Mbps and uses baseband transmissions. 10Base2 typically is implemented as a bus topology, but it could be a mix of a bus and a star topology. The cable type that we use is determined by the character at the end of the name of the architecture —in this case a 2. The 2 implies 200 meters. Now, what type of cable is limited to approximately 200m? Thinnet is limited to approximately 200m (185m to be exact). The only characteristic we have not mentioned is the access method that is used.
All Ethernet environments use CSMA /CD as a way to put data on the wire.
The following list summarizes features of 10Base2:
Ø Baseband communication
Ø 10 Mbps transfer rate
Ø Maximum distance of 185 meters per network segment
Ø 30 hosts per segment
Ø 0.5 meters minimum distance between hosts
10Base5
The 10Base5 Ethernet architecture runs at 10 Mbps and uses baseband transmission as well. It was also implemented as a bus topology. The cable it uses is limited to approximately 500 meters, which is thicknet, and it uses CSMA /CD as the access method. The thicker copper core in the wire allows the signal to travel further than is possible with thinnet.
The following list summarizes features of 10Base5:
Ø Baseband communication
Ø 10 Mbps transfer rate
Ø Maximum distance of 500 meters per network segment
Ø 100 hosts per segment
Ø 2.5 meter minimum distance between hosts
10BaseT
The 10BaseT Ethernet architecture runs at 10 Mbps and uses baseband transmission. It uses a star topology with a hub or switch at the center, allowing all systems to connect to one another. The cable it uses is CAT 3 UTP, which is the UTP cable type that runs at 10 Mbps. Keep in mind that most cable types are backward compatible, so you could have CAT 5 UTP cabling in a 10BaseT environment. But because the network cards and hubs are running at 10 Mbps, that is the maximum transfer speed you will get, even though the cable supports more.
Like all Ethernet environments, 10BaseT uses CSMA /CD as the access method.
10BaseFL
The 10BaseFL Ethernet architecture allows for a 10-Mbps Ethernet environment that runs on fiber-optic cabling. The purpose of the fiber-optic cabling is to use it as a backbone to allow the network to reach greater distances.
Fast Ethernet (100BaseTX and 100BaseFX)
These two standards are part of the 100BaseX family, which is known as fast Ethernet. The different fast Ethernet flavors run at 100 Mbps, use a star topology, use CSMA / CD as an access method, and differ in the type of cabling used. 100BaseTX uses two pairs (four wires) in the CAT 5 cabling, whereas 100BaseFX uses two strands of fiber instead of twisted-pair cabling.
Gigabit Ethernet
Gigabit Ethernet is becoming the de facto of network architectures today. With Gigabit Ethernet we can reach transfer rates of 1000 Mbps (1 Gbps), using traditional media such as coaxial, twisted-pair, and fiber-optic cabling. There are two standards for Gigabit: IEEE 802.3z and IEEE 802.3ab.
IEEE 802.3z
The IEEE 802.3z standard defines Gigabit Ethernet that runs over fiber-optic cabling or coaxial cabling. There are three types of Gigabit Ethernet that fall under this standard:
1000Base-SX is the Gigabit Ethernet architecture that runs at 1000 Mbps over multimode fiber (MMF) optic cabling. This architecture is designed for short distances of up to 550 meters.
1000Base-LX is the Gigabit Ethernet architecture that runs at 1000 Mbps over single-mode fiber (SMF) optic cabling. This architecture supports distances up to 3 kilometers.
1000Base-CX is the Gigabit Ethernet architecture that runs at 1000 Mbps over coaxial cable and supports distances of up to 25 meters.
IEEE 802.3ab
The IEEE 802.3ab standard, known as 1000BaseTX, defines Gigabit Ethernet that runs over twisted-pair cabling and uses characteristics of 100BaseTX networking, including the use of RJ-45 connectors and the access method of CSMA /CD. Like 100BaseTX, 1000BaseTX uses CAT 5, CAT 5e, and even CAT 6 unshielded twisted-pair, the difference being that 100BaseTX runs over two pairs (four wires) while 1000BaseTX runs over four pairs (all eight wires).
10-Gigabit Ethernet:
There are standards for 10-Gigabit Ethernet (10,000 Mbps) that have been developed that use fiber-optic cabling:
10GbaseSR runs at 10 Gbps and uses “short-range” multimode fiber-optic cable, which has a maximum distance of 100 meters.
10GBaseLR runs at 10 Gbps and uses “long-range” single-mode ?ber-optic cable, which has a maximum distance of 10 kilometers.
10GbaseER runs at 10 Gbps and uses “extra-long-range” single-mode ?ber- optic cable which has a maximum distance of 40 kilometers.
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