NETWORK TECHNOLOGIES
1. ETHERNET
2. TOKEN RING
3. FDDI [Fiber Distributed Data Interface ]
ETHERNET
- 10 MbPS
- Revisions
- Fast Ethernet [ IEEE 802.3U ] 100 MbPS
- Gigabit Ethernet [ IEEE 802.5 ] 100 MbPS or 1 GbPS
CSMA/CD [Carrier Sense Multiple Access / Collision Detection]
- Ethernet` at Data Link layer is responsible for Ethernet addressing, commonly referred to as hardware addressing or MAC addressing
- Ethernet is also responsible for framing packets received from the network layer and preparing them for transmission on the local network through Ethernet CONTENTION Media Access Method
ETHERNET FRAME FORMAT IEEE 802.3
PRE – Preamble – 7 bytes in alternating 1’s, 0’s – indicating the receiver stations that frame is coming
SFD – Start Frame Delimiter / synch – 1 byte
1,0,1,0,1,0,10,1 ------------- 1,1,1,1,1,1,1,1
Alternations ------------------ all 1’s
1, 0
- PRE uses either SFD or synch
DA – Destination Address – 6 bytes
LSB is 0 – Individual Address
1 – Group Address
TOKEN RING [IEEE 802.5]
- No collisions
- Ideal for applications [factory automation]
- 4 or 16 MbPS
Logically a ring but physically a star configuration to MAU relays
- Token ring LANs continuously pass a token or a Token Ring frame
- MAU [ Outstation Access Unit]
FDDI [Fiber Distributed Data Interface]
- 100 MbPS Token passing network
- Fiber optic cable with mass length of 2 km
- Dual-ring architecture for redundancy
- Used for corporate and carrier backbones
CDDI [Copper Distributed Data Interface]
- implements FDDI over STP and UTP cable
Dual Ring Architecture
- Primary ring for data transmissions
- Secondary ring for reliability and robustness
Components
- Single attachment station ( SAS ) for PC’s
- Dual attachment stations ( DAS ) for servers
- Concentrator
FDDI concentrator
- also called as Dual- attached concentrator (DAC)
- Building block of an FDDI network
- Attaches directly to both rings and ensures that any SAS failure or power-down does not bring down the ring