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what is network topology and rules of computer networking?

what is networkjing protocols?

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1. Network Topologies http://www.delmar.edu/Courses/ITNW2313/network.htm Rules? I spent a very long time learning computer networking. Go take CCNA 1-4 if you want the rules, otherwise you wont get a good answer. Networking protocols http://www.techfest.com/networking/prot.htm
2. Well, NETWORK TOPOLOGY Topology refers to the way in which the network of computers is connected. Each topology is suited to specific tasks and has its own advantages and disadvantages. The choice of topology is dependent upon type and number of equipment being used planned applications and rate of data transfers required response times cost There are FOUR major competing topologies Bus Ring Star FDDI Most networking software support all topologies. -------------------------------------------------------------------------------- Bus Topology all workstations connect to the same cable segment commonly used for implementing Ethernet at 10mbps the cable is terminated at each end wiring is normally done point to point a faulty cable or workstation will take the entire LAN down two wire, generally implemented using coaxial cable during the 1980's The bus cable carries the transmitted message along the cable. As the message arrives at each workstation, the workstation computer checks the destination address contained in the message to see if it matches it's own. If the address does not match, the workstation does nothing more. If the workstation address matches that contained in the message, the workstation processes the message. The message is transmitted along the cable and is visible to all computers connected to that cable. There are THREE common wiring implementations for bus networks 10Base2 (thin-net, CheaperNet) 50-ohm cable using BNC T connectors, cards provide transceiver 10Base5 (ThickNet) 50-ohm cable using 15-pin AUI D-type connectors and external transceivers 10BaseT (UTP) UTP cable using RJ45 connectors and a wiring centre -------------------------------------------------------------------------------- Physical Implementation Of A Bus Network The above diagram shows a number of computers connected to a Bus cable, in this case, implemented as Thin Ethernet. Each computer has a network card installed, which directly attaches to the network bus cable via a T-Connector. It is becoming common to use 10BaseT (UTP) for implementing Ethernet LANS. Each workstation is wired in star fashion back to a concentrator wiring centre (hub). The hub is a multi-port device supporting up to about 32 ports. One of these ports is connected to a server, or the output of the hub can be connected to other hubs. -------------------------------------------------------------------------------- Ethernet 802.3: Carrier Sense Multiple Access with Collision Detection (CSMA/CD) This protocol is commonly used in bus (Ethernet) implementations. Multiple access refers to the fact that in bus systems, each station has access to the common cable. Carrier sense refers to the fact that each station listens to see if no other station is transmitting before sending data. Collision detection refers to the principle of listening to see if other stations are transmitting whilst we are transmitting. In bus systems, all stations have access to the same cable medium. It is therefore possible that a station may already be transmitting when another station wants to transmit. Rule 1 is that a station must listen to determine if another station is transmitting before initiating a transmission. If the network is busy, then the station must back off and wait a random interval before trying again. Rule 2 is that a station which is transmitting must monitor the network to see if another station has begun transmission. This is a collision, and if this occurs, both stations must back off and retry after a random time interval. As it takes a finite time for signals to travel down the cable, it is possible for more than one station to think that the network is free and both grab it at the same time. CSMA/CD models what happens in the real world. People involved in group conversation tend to obey much the same behavior. -------------------------------------------------------------------------------- Physical Bus Cable Limits 10Base2 THIN ETHERNET NETWORK LAYOUT Limitations maximum number of trunk segments = 5 maximum trunk segment length = 607 feet (185 meters) maximum network trunk cable = 3035 feet (925 meters) maximum number of stations on a trunk segment = 30 minimum distance between T connectors = 1.5 feet (0.5 meters) Rules each end of the trunk segment is terminated in 50-ohms one of the terminators is grounded connector splices are kept to a minimum Cabling BNC-T type connectors RG58-AU 50-ohm cable, 0.2" -------------------------------------------------------------------------------- 10Base5 THICK ETHERNET NETWORK LAYOUT Limitations maximum number of trunk segments = 5 maximum trunk segment length = 1640 feet (500 meters) maximum network trunk cable = 8200 feet (2500 meters) maximum number of stations on a trunk segment = 100 minimum distance between transceivers = 8 feet (2.5 meters) maximum transceiver cable length = 165 feet (50 meters) Rules each end of the trunk segment is terminated in 50-ohm one of the terminators is grounded connector splices are kept to a minimum Cabling Transceivers 802.3 50-ohm cable RG-11 Male DIX connector Wiring of the DIX Connector Pin Ethernet IEEE 802.3 1 Shield Control-in Shield 2 Collision presence+ Control-in A 3 Transmit+ Data-out A 4 Reserved Data-in Shield 5 Receive+ Data-in A 6 Power return Voltage common 7 Reserved Control-out A 8 Reserved Control-out Shield 9 Collision presence- Control-in B 10 Transmit- Data-out B 11 Reserved Data-out Shield 12 Receive- Data-in B 13 Power Voltage 14 Reserved Voltage Shield 15 Reserved Control-out B Shell --- Protective Ground -------------------------------------------------------------------------------- 10BaseT UTP NETWORK LAYOUT Limitations maximum segment length of 100 Meters Hub to Hub or repeater to repeater links limited to 100 Meters Rules star topology 4 repeater/5 segment rule of 10Base5 is retained only two nodes per segment are allowed Cabling RJ-45 Connectors Category 3 UTP minimum, preferably Category 5 -------------------------------------------------------------------------------- Bus Network Topology Summary Advantages Disadvantages Easy to implement Limits on cable length and Workstation numbers Low Cost Difficult to isolate network faults A cable fault affects all workstations As the number of workstations increase, the speed of the network slows down NETWORK TOPOLOGY Topology refers to the way in which the network of computers is connected. Each topology is suited to specific tasks and has its own advantages and disadvantages. The choice of topology is dependent upon type and number of equipment being used planned applications and rate of data transfers required response times cost There are FOUR major competing topologies Bus Ring Star FDDI Most networking software support all topologies. -------------------------------------------------------------------------------- Bus Topology all workstations connect to the same cable segment commonly used for implementing Ethernet at 10mbps the cable is terminated at each end wiring is normally done point to point a faulty cable or workstation will take the entire LAN down two wire, generally implemented using coaxial cable during the 1980's The bus cable carries the transmitted message along the cable. As the message arrives at each workstation, the workstation computer checks the destination address contained in the message to see if it matches it's own. If the address does not match, the workstation does nothing more. If the workstation address matches that contained in the message, the workstation processes the message. The message is transmitted along the cable and is visible to all computers connected to that cable. There are THREE common wiring implementations for bus networks 10Base2 (thin-net, CheaperNet) 50-ohm cable using BNC T connectors, cards provide transceiver 10Base5 (ThickNet) 50-ohm cable using 15-pin AUI D-type connectors and external transceivers 10BaseT (UTP) UTP cable using RJ45 connectors and a wiring centre -------------------------------------------------------------------------------- Physical Implementation Of A Bus Network The above diagram shows a number of computers connected to a Bus cable, in this case, implemented as Thin Ethernet. Each computer has a network card installed, which directly attaches to the network bus cable via a T-Connector. It is becoming common to use 10BaseT (UTP) for implementing Ethernet LANS. Each workstation is wired in star fashion back to a concentrator wiring centre (hub). The hub is a multi-port device supporting up to about 32 ports. One of these ports is connected to a server, or the output of the hub can be connected to other hubs. -------------------------------------------------------------------------------- Ethernet 802.3: Carrier Sense Multiple Access with Collision Detection (CSMA/CD) This protocol is commonly used in bus (Ethernet) implementations. Multiple access refers to the fact that in bus systems, each station has access to the common cable. Carrier sense refers to the fact that each station listens to see if no other station is transmitting before sending data. Collision detection refers to the principle of listening to see if other stations are transmitting whilst we are transmitting. In bus systems, all stations have access to the same cable medium. It is therefore possible that a station may already be transmitting when another station wants to transmit. Rule 1 is that a station must listen to determine if another station is transmitting before initiating a transmission. If the network is busy, then the station must back off and wait a random interval before trying again. Rule 2 is that a station which is transmitting must monitor the network to see if another station has begun transmission. This is a collision, and if this occurs, both stations must back off and retry after a random time interval. As it takes a finite time for signals to travel down the cable, it is possible for more than one station to think that the network is free and both grab it at the same time. CSMA/CD models what happens in the real world. People involved in group conversation tend to obey much the same behavior. -------------------------------------------------------------------------------- Physical Bus Cable Limits 10Base2 THIN ETHERNET NETWORK LAYOUT Limitations maximum number of trunk segments = 5 maximum trunk segment length = 607 feet (185 meters) maximum network trunk cable = 3035 feet (925 meters) maximum number of stations on a trunk segment = 30 minimum distance between T connectors = 1.5 feet (0.5 meters) Rules each end of the trunk segment is terminated in 50-ohms one of the terminators is grounded connector splices are kept to a minimum Cabling BNC-T type connectors RG58-AU 50-ohm cable, 0.2" -------------------------------------------------------------------------------- 10Base5 THICK ETHERNET NETWORK LAYOUT Limitations maximum number of trunk segments = 5 maximum trunk segment length = 1640 feet (500 meters) maximum network trunk cable = 8200 feet (2500 meters) maximum number of stations on a trunk segment = 100 minimum distance between transceivers = 8 feet (2.5 meters) maximum transceiver cable length = 165 feet (50 meters) Rules each end of the trunk segment is terminated in 50-ohm one of the terminators is grounded connector splices are kept to a minimum Cabling Transceivers 802.3 50-ohm cable RG-11 Male DIX connector Wiring of the DIX Connector Pin Ethernet IEEE 802.3 1 Shield Control-in Shield 2 Collision presence+ Control-in A 3 Transmit+ Data-out A 4 Reserved Data-in Shield 5 Receive+ Data-in A 6 Power return Voltage common 7 Reserved Control-out A 8 Reserved Control-out Shield 9 Collision presence- Control-in B 10 Transmit- Data-out B 11 Reserved Data-out Shield 12 Receive- Data-in B 13 Power Voltage 14 Reserved Voltage Shield 15 Reserved Control-out B Shell --- Protective Ground -------------------------------------------------------------------------------- 10BaseT UTP NETWORK LAYOUT Limitations maximum segment length of 100 Meters Hub to Hub or repeater to repeater links limited to 100 Meters Rules star topology 4 repeater/5 segment rule of 10Base5 is retained only two nodes per segment are allowed Cabling RJ-45 Connectors Category 3 UTP minimum, preferably Category 5 -------------------------------------------------------------------------------- Bus Network Topology Summary Advantages Disadvantages Easy to implement Limits on cable length and Workstation numbers Low Cost Difficult to isolate network faults A cable fault affects all workstations As the number of workstations increase, the speed of the network slows down FDDI Topology 100mbps normally implemented over fiber optic (fast-Ethernet, UTP) dual redundancy built in by use of primary and secondary ring automatic bypassing and isolation of faulty nodes Fiber Distributed Data Interface FDDI is based on two counter rotating 100-Mbit/sec token-passing rings. The rings consist of point to point wiring between nodes which repeat the data as it is received. The primary ring is used for data transmission; the secondary is used for data transmission or to back up the primary ring in the event of a link or station failure. FDDI supports a sustained transfer rate of about 80Mbps, a maximum of 1000 connections (500 nodes) and a total distance of 200 kilometers end to end. There is a maximum distance of 2 kilometers between active nodes. FDDI Station Types There are two main types of stations, class A which attach directly to dual rings; or class B which attach to a station acting as a concentrator. A concentrator is a specialized workstation that attaches to the ring and has multiple ports that allow attachment of other devices in a physical star configuration. These may be cascaded. -------------------------------------------------------------------------------- Logical Networks versus Physical Networks A logical network describes how the network operates. A physical network describes how the network has been cabled. It is thus possible to have a physical star, logical bus network. In other words, the network operates as a bus network, but the cabling has been implemented using star topology.