Introduction to LAN TDC 363 Week 2 Networking Hardware Book: Chapter 5 Topologies and Access Methods Book: Chapter 6 01/10/08 TDC363-02 1 Outline (Chap 5) Network Equipment NIC Repeater and Hub Bridge and Ethernet Switch Router 01/10/08 TDC363-02 2 Network Adapters Also called network interface cards (NICs) Connectivity devices enabling a workstation, server, printer, or other node to receive and transmit data over the network media Layer 2 device Why is NIC a LayerLayer--22 device? 01/10/08 TDC363-02 3 1 Types of Network Adapters Old Days Industry Standard Architecture (ISA) MicroChannel Architecture (MCA) Extended Industry Standard Architecture (EISA) PihPeriphera lCl Componen tItt Interconnec t (PCI) PCI Express Personal Computer Memory Card International Association (PCMCIA) Universal Serial Bus (USB) Compact Flash (CF) Card NIC on Motherboard 01/10/08 TDC363-02 4 Installing and Configuring Network Adapter Hardware (a Historical Perspective) Jumper Small, removable piece of plastic that contains a metal receptacle 01/10/08 TDC363-02 5 NIC Configuration Information Ref. p. 240 01/10/08 TDC363-02 6 2 Hubs and Repeaters LayerLayer--11 device Repeater: 2-2-portport hub Hub: mutimuti--portport repeater Connectivity device that regenerates digital signal Eliminate Noise (Attenuation) Signal received on one port is broadcast to all other ports 01/10/08 TDC363-02 7 Network of Hubs 01/10/08 TDC363-02 8 Bridges Like a repeater, a bridge has a single input and single output port Unlike a repeater, it can interpret the data it retransmits LayerLayer--22 device 01/10/08 TDC363-02 9 3 Ethernet Switches switch ::= multimulti--portport bridge Divide a network into smaller logical pieces (multiple collision domains) modular desktop or stackable 01/10/08 TDC363-02 10 CutCut--ThroughThrough Mode and Store and Forward Mode CutCut--throughthrough mode Switching mode in which switch reads a frame’s header and decides where to forward the data before it receives the entire packet CutCut--throughthrough switches can detect runts, or packet fragments Store and forward mode Switching mode in which switch reads the entire data frame into its memory and checks it for accuracy before transmitting the information 01/10/08 TDC363-02 11 Delay in Store-Store-andand--ForwardForward Max Frame Size 1500 bytes (12,000 bit) 10BaseT Network (10M bps) 12,000 ÷ 10M = 1,200 µsµs 100BaseTX N etwork (100M b ps) 12,000 ÷ 100M = 120 µsµs Gigabit Ethernet (1G bps) 12,000 ÷ 10M = 12 µµss 01/10/08 TDC363-02 12 4 Routers Multiport connectivity device Can integrate LANs and WANs running at different transmission speeds and using a variety of protocols Routers operate at the Network layer (Layer 3) of the OSI Model 01/10/08 TDC363-02 13 Routers Modular router Router with multiple slots that can hold different interface cards or other devices 01/10/08 TDC363-02 14 Router Features and Functions Filter out broadcast transmission to alleviate network congestion Prevent certain types of traffic from getting to a network Support simultaneous local and remote activity Provide high network fault tolerance through redundant components Monitor network traffic and report statistics to a MIB Diagnose internal or other connectivity problems and trigger alarms 01/10/08 TDC363-02 15 5 Router Features and Functions Static routing Technique in which a network administrator programs a router to use a specified paths between nodes Dynamic routing Automatically calculates best path between nodes and accumulates this information in a routing table Hop Term used in networking to describe each trip data take from one connectivity device to another 01/10/08 TDC363-02 16 Router Features and Functions 01/10/08 TDC363-02 17 Routing Protocols To determine the best path, routers communicate with each other through routing protocols In addition to its ability to find the best path, a routing protocol can be characterized according to its convergence tidbdidhhdime and bandwidth overhead Convergence time The time it takes for a router to recognize a best path in the event of a change or outage Bandwidth overhead Burden placed on an underlying network to support the routing protocol 01/10/08 TDC363-02 18 6 Routing Protocols The four most common routing protocols: RIP (Routing Information Protocol) for IP RIPRIP--IIII OSPF (Open Shortest Path First) for IP EIGRP (Enhanced Interior Gateway Routing Protocol) for IP, IPX, and AppleTalk BGP (Border Gateway Protocol) for IP required for routing on the public Internet 01/10/08 TDC363-02 19 Brouters and Routing Switches Bridge router Also called a brouter Industry term used to describe routers that take on some characteristics of bridges Routing switch Router hybrid that combines a router and a switch 01/10/08 TDC363-02 20 Gateways Standard definition: a layerlayer--77 device to interconnect two distinct networks. Practical definition: a device to interconnect two networks. Combination of networking hardware and software that connects two dissimilar kinds of networks Popular types of gateways include: EE--mailmail gateways IBM host gateways Internet gateways LAN gateways 01/10/08 TDC363-02 21 7 HigherHigher--LayerLayer Switches Switch capable of interpreting Layer 3 data is called a Layer 3 switch What is the difference between a Layer 3 switch and a router? Switch capable of interpreting Layer 4 data is called a Layer 4 switch What kdfkind of layer 4 data is use d to switch? These higherhigher--layerlayer switches may also be called routing switches or application switches LayerLayer--77 switch ??? Confusion in terminology??? 01/10/08 TDC363-02 22 Chapter Outline (Chap. 6) LAN Topology WAN Topology Ethernet Token Ring Other LAN Technologies: FDDI and ATM 01/10/08 TDC363-02 23 Simple Physical Topologies Physical topology Physical layout of a network A Bus topology consists of a single cable, called a bus, connecting all nodes on a network without intervening connectivity devices Q: any problem with this topology? 01/10/08 TDC363-02 24 8 Ring Topology Each node is connected to the two nearest nodes so the entire network forms a circle One method for passing data on ring networks is token passing 01/10/08 TDC363-02 25 Star Topology Every node on the network is connected through a central device 01/10/08 TDC363-02 26 StarStar--wiredwired Ring Topology Hybrid topology Complex combination of the simple physical topologies StarStar--wiredwired ring StarStar--wiredwired topologies use physical layout of a star in conjunction with token ring-ring-passingpassing data transmission method 01/10/08 TDC363-02 27 9 StarStar--wiredwired Bus Topology In a starstar--wiredwired bus topology, groups of workstations are starstar--connectedconnected to hubs and then networked via a single bus 01/10/08 TDC363-02 28 EnterpriseEnterprise--WideWide Topologies Enterprise An entire organization Backbone networks SilbkbSerial backbone Distributed backbone Collapsed backbone Parallel backbone 01/10/08 TDC363-02 29 Serial & Distributed Backbone Serial backbone Two or more hubs connected to each other by a single cable Distributed backbone Hubs connected to a series of central hubs or routers in a hierarchy Serial Backbone 01/10/08 TDC363-02 30 10 Collapsed Backbone Collapsed ::= divide a single collision domain into multiple ones Uses a router or switch as the single central connection point for multiple subnetworks 01/10/08 TDC363-02 31 Parallel Backbone Collapsed backbone arrangement that consists of more than one connection from central router or switch to each network segment Ref: Figure 6-10: A parallel backbone network 01/10/08 TDC363-02 32 Logical Topologies Refer to the way in which data are transmitted between nodes Describe the way: Data are packaged in frames Electrical pulses are sent over network’s physical media Logical topology may also be called network transport system Communication at layer 2. 01/10/08 TDC363-02 33 11 Switching Circuit Message Packet Switching Switching Switching Frame Cell Switching Switching Discussion: switching vs. transmission. What are the differences? Note: ATM is NOT a circuit switching technology. 01/10/08 TDC363-02 34 Practical Questions As a network engineer, you are assigned to design a campus network. What is the technology to be deployed at the entrance facility? From carrier’s central office From the main building of the campus What is the technology to be deployed at the equipment room? What is the technology to be deployed at the telecom closet? What is the technology to be deployed at the work area (i.e., desktop)? 01/10/08 TDC363-02 35 What are my choices? Ethernet 10BaseT, 10Base2, 10Base5 Fast Ethernet 1G and 10G Ethernet TkToken Ring 100BaseVG FDDI ATM [Wireless] 01/10/08 TDC363-02 36 12 Ethernet Most popular industry use and acceptance Product availability Many vendors Relatively low cost High knowledge base Standardized for multiple media types Twisted pair (10M, 100M, and 1G) Optical fiber (10M, 100M, 1G, and 10G) Coaxial cable (10Base2, 10Base5) 01/10/08 TDC363-02 37 Ethernet Standards Specifications Ethernet standards define Physical and MAC layers of the OSI model only. Physical layer Electrical characteristics of cable cable connectors, including maximum lengths Bit encoding (e.g., Manchester coding) and transmission rate (10/100/1000 Mbps) Medium Access Control (MAC) layer Ethernet frame format and addressing Access protocol = Carrier Sense Multiple Access with