Ethernet Hardware Cabling –Twisted Pair 100 Meter length limit Point to Point –Fiber Expense Point to Point 2000 meter length limit

Ethernet Cabling Cont. –Coax (10 MB ethernet only) inexpensive Bus System (party line) Thin(185 Meter length limit) –30 connections/cable, min 18 inches between Thick (500 meter length limit) –200 connections, min 2.5M between Transceivers

10baseT/100baseT 2 twisted pairs Transmit/Receive 100 meter/328 foot distance limit Uses standard telephone modular plugs Category 3 (10mb) vs. Category 5 (100mb)

White/Orange Orange/White White/Green Green/White Blue/White White/Blue White/Brown Brown/White

Ethernet Twist (hub-hub) W/O O/W G/W W/G

Hubs and Repeaters Hubs (Star topology) Twisted Pair Fiber, Coax, Twisted Pair Backbone (Twisted Pair may need a twist!)

Hub Advantages Standard Telephone Wiring Standard Punch Blocks and Cross Connects Ability to disable a single port Easier to monitor traffic patterns Visible Indication of Link Status If a wire is cut only one port is affected –Unless the backbone feed is cut!

Coaxial Installation Multidrop (Bus topology) T T=terminator (50 ohm resistor) Repeater Backbone Other computers T T T

Repeater Rule 10MB 3 repeater rule Repeater System 1 Sys 2 Sys3 System 1 can talk to Sys 2 but not Sys3

Network Diameter (100MB) 205 Meter Limit Repeater 100M 5M 100M 10MB diameter is 500M

Switches and Bridges Repeater Bridge

Bridge Insides Interface Filter based on ethernet address LAN A LAN B

Switch Insides A B C D E F G Switching based on ethernet address

100baseT to 10baseT Hub/Bridge 10baseT 100baseT 10baseT hub 100baseT hub 100baseT to 10baseT Bridge Module

Ethernet Rules 3 repeater (populated) limit 5 repeater per segment limit 7 bridges Cable lengths Number of stations/cable

How to get around limits? Hubs Switch ROUTER Other Lans To the Internet (switching based on IP address) Firewall

Ethernet Errors Carrier Loss Collisions –How many are tolerable? Jabber Runts –Causes Tools –tcpdump, snoop, traceroute, ping

Token Ring Mic (Media Interface Connector at each computer) 4 or 16 MB/s

MAU Multistation Access Unit `` Ring inRing out Computer Ports

Appletalk EtherTalk –uses ethernet LocalTalk –Serial link at 230KB/s TokenTalk AppleShare –File Sharing Zones

Routers Advantages –Multi Protocol –Broadcast filtering Disadvantages –Cost –Complexity Configuration

Complex System Modems ATM Switch FDDI Concentrator A B C D Buildings Router Primary router To Internet

Routed vs. Switched Network Routed –IP/IPX Layer Routing –Subnetted Network –Broadcast Filtering –More Expensive –Complex Configuration –Better Control Switched –Ethernet Layer Routing –Flat Network –Broadcasts progagate –Less Expensive –Simple Configuration –Loose Control –Network Diameter limit