IST 201 Chapter 5

LAN Technologies Ethernet – most widely used technology in LANS In 1970, developed and implemented by: Digital Intel Xerox IEEE standard is based on the DIX specification.

Ethernet Specifications – Ethernet 802.3u – FastEthernet 802.3z – Gigabit Ethernet (Fiber) 802.3ab – Gigabit Ethernet (UTP) 802.3ae – 10 Gigabit Ethernet Layer 1 specification

Media Carries flow of information through a LAN Operates at Layer 1 Cat 5 UTP – primary media in Ethernet networks NIC Ports RJ45 AUI – attachment unit interface 15 pin connector Unusual Requires a transceiver to convert to RJ45

UTP Straight Through Cable One end: ow o gw bl blw g brw br Transmit Receive Used for: Switch  router Computer  switch Computer  hub

Crossover Cable One end: ow o gw bl blw g brw br One end: gw g ow bl blw o brw br Used for: Router  router Computer  computer Computer  router Switch  switch Switch  hub

Roll-over Cable One end: ow o gw bl blw g brw br One end: br brw g blw bl gw o ow

Hubs Multiport repeater Concentrators – central connection point Active – has power re-generates signal & sends out all ports except receiving Intelligent – active microchip w/diagnostics expensive good for troubleshooting Passive – no power connection point does not regenerate the signal

5-4-3 Rule No more than 5 segments connect using 4 hubs Only 3 segments can have hosts Ensures that the signal reaches the destination within a specified time limit to avoid collisions..

Wireless RF Infrared – req line of site Microwaves No wires Mobile Versatile Convenient

Bridges Data link layer Connects network segments Builds MAC table of hosts on each segment Filter – looks at the destination MAC address, drops the frame if the destination is on the same segment. Flood – doesn’t have destination MAC address in the bridge table, sends out all ports except receiving one.. Forward – picks up frame and forwards out to the correct segment

Switch Multiport bridge Makes decisions based on MAC address Builds MAC table (switching table) Reduce traffic Increase bandwidth Filter Flood Forward breaks up collision domain

NIC Printed circuit board providing network connectivity layers 1 and 2 but it is considered a layer 2 device MAC address

Peer to Peer Networks Computers connected to act as equal partners No centralized administration Ea. computer may act as a server or client to other computers 10 or fewer Share files Share printers Easy to install Does not scale well Security is low

Client/Server Centralized control Common admin Increased security Scalable – requires authentication Server – additional processing power RAM Single point of failure

WANs Networks connected together over a wide geographic area. Use serial connections Bits of data are transmitted sequentially over a single channel Dedicated leased lines ISDN DSL Cable

Leased Lines T1 – Mbps T3 – Mbps Run PPP or Frame Relay Encapsulations PPP – Point to Point Protocol Frame Relay

ISDN Integrated Services Digital Network 128 kbps Dial on demand connections BRI (Basic Rate Interface) 2 B channels (64 kbps bearer channels) - data 1 D channel (16 kbps delta channel) – signaling and link management Typically uses PPP encapsulation.

DSL Digital Subscriber Line 128 kbps – 6.1 Mbps Dial-up connectivity Uses telephone infrastructure

Cable Up to 8 Mbps (maybe higher?) Uses existing cable tv infrastructure Coaxial cable

Router Purpose Route packets from source to destination with a LAN Provide connectivity from the LAN to the WAN. Segments a network into subnetworks Breaks up broadcast domains.

Router WAN Serial Ports V.35 connectors DTE (data terminal equipment) – on the customer side of the connection DCE (data circuit-terminating equipment) on the ISP side. Provides clock rate CSU/DSU – channel service unit/data service unit Another device that provides clocking with a direct connection.

Configuring the Router Need management connection Roll-over cable/console cable Connects serial port of computer using DB9 to RJ45 transceiver to Console port (RJ45) on the router Terminal emulation software Hyperterminal w/these settings on the COM port 9600 bps 8 data bits No parity 1 stop bit None

Console v. Auxiliary Port Console port is used for initial router configuration Console management connection is between a pc and the router console port. Management via a modem connection is possible for configuration changes. Modem is connected to the auxiliary port

Cisco 2500 Router DB-15 port Requires a transceiver to convert to a Ethernet port (RJ45)