Chapter Six Networking Hardware Network Interface Cards

Chapter Six Networking Hardware

Network Interface Cards (NICs) ¨ Connectivity devices enabling a workstation, server, printer or other node to receive and transmit data over the network media ¨ Sometimes called network adapters ¨ NICs are physical and data link layer devices

Network Interface Cards (NICs) Types of NICs ¨ Industry Standard Architecture (ISA) ¨ Micro. Channel Architecture (MCA) ¨ Extended Industry Standard Architecture (EISA) ¨ Peripheral Component Interconnect (PCI) FIGURE 6 -1 Four primary bus architectures

Network Interface Cards (NICs) ¨ NICs may connect to interfaces other than a PC’s bus. For example: – For laptop computers, Personal Computer Memory Card International Association slots may be used to connect NICs • PCMCIA • Also called PC card • Developed in the early 1990 s to provide a standard interface for connecting any type of device to a portable computer

Network Interface Cards (NICs) FIGURE 6 -3 Typical PCMCIA NIC FIGURE 6 -4 Parallel port NIC

Network Interface Cards (NICs) FIGURE 6 -5 Wireless NIC and transceiver FIGURE 6 -6 Ethernet NICs for printers

Network Interface Cards (NICs) ¨ Installing NICs – Installing hardware – Configuring software • Installing driver—software the tells OS how to communicate with NIC • Specifying IRQ, memory range, I/O port – Configuring firmware • Utilities supplied with NIC that enables you to write configuration changes to the EPROM chip on the NIC card

Installing and Configuring NIC Software ¨ After NIC is physically installed, restart the PC ¨ The driver for the NIC card must be installed and configuration information entered

Repeaters ¨ Connectivity device that regenerates and amplifies an analog or digital signal FIGURE 6 -14 Repeater

Hubs ¨ Multiport repeater containing one port that connects to a network’s backbone and multiple ports that connect to a group of workstations

Hubs ¨ Passive hubs – Only repeats signal ¨ Active hubs – Regenerate or amplify signal ¨ Intelligent hubs – Possesses processing capabilities ¨ Standalone Hubs – Serves a workgroup of computers that are separated from the rest of the network ¨ Stackable Hubs – Designed to be linked with other hubs in a single telecommunications closet

Modular Hubs and Intelligent Hubs ¨ Modular hub – Provide a number of interface options within one chassis • Connection point for networks using with different cabling, e. g. , 10 base 2 and 10 base. T ¨ Intelligent hubs – Also called managed hubs – MIB (management information base) • Collection of data used by management programs to analyze network performance

Choosing the Right Hub ¨ Performance ¨ Cost ¨ Size and growth ¨ Security ¨ Management benefits ¨ Reliability

Bridges ¨ Reduce network traffic bottleneck ¨ Regenerate signals to extend network lengths ¨ Operate at the Data Link Layer of the OSI model because they have to read packet addresses

Bridges ¨ Filtering database – Collection of data created and used by a bridge that correlates the MAC addresses of connected workstations with their locations – Also known as a forwarding Segment 1 table Bridge Segment 2

Bridges ¨ Transparent Bridging – Method used on most Ethernet networks ¨ Source Route Bridging – Method used on most Token Ring networks ¨ Translation Bridging – Method that can connect Token Ring and Ethernet networks

Switches ¨ Switches subdivide a network into smaller logical pieces ¨ Collision domain – Portion of a LAN encompassing devices that may cause and detect collisions among their group ¨ Switches are layer 2 devices

Switches ¨ Switch Methods – Cut-through mode—switch reads only the header to determine where to forward the packet. – Store and forward mode—switch reads the entire packet and checks for accuracy before forwarding

Using Switches to Create VLANs ¨ Virtual local area networks (VLANs) – Means by which a switch can logically group a number of ports into a broadcast domain

Higher-Layer Switches ¨ Switch capable of interpreting Layer 3 is called a Layer 3 switch ¨ Switch capable of interpreting Layer 4 is called a Layer 4 switch ¨ Higher-layer switches may also be called routing switches or application switches

Routers ¨ Routers connect two or more networks ¨ Consist of hardware and software – Hardware • Network server, separate computer, special black box • Physical interface for various networks – Software • Operating system and Routing protocol ¨ Routers operated at the Network layer

Routers ¨ Can connect dissimilar LANs and WANs running at different transmission speeds and using a variety of protocols ¨ Read the network address information in a packet ¨ Calculates the optimal path to a particular network – Reroute packets if a path is not available ¨ Routing tables stored in the router list all known addresses and possible paths

How do Routers Select Routes ¨ Dynamic route selection – Routers continually adjusts the routes based on network conditions ¨ Static route selection – Route is designated in a table and router cannot vary from that route

Router Features and Functions ¨ Filter out broadcast transmission to alleviate network ¨ ¨ congestion Prevent certain types of traffic from getting to a network 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

Routers

Routing Protocols ¨ Means by which routers communicate with each other about network status ¨ Routing protocol characteristics – 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

Routing Protocols ¨ RIP (Routing Information Protocol) for IP and IPX ¨ OSPF (Open Shortest Path First) for IP – Best path refers to the most efficient route from one node on a network to another ¨ EIGRP (Enhanced Interior Gateway Routing Protocol) for IP, IPX, and Apple. Talk ¨ BGP (Border Gateway Protocol) for IP

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 – Another term for a Layer 3 or Layer 4 switch

Gateways ¨ Combination of networking hardware and software that connects two dissimilar kinds of networks – – E-mail gateway IBM host gateway Internet gateway LAN gateway