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)

1

2

3

4

5

7

8

6

White/Orange

Orange/White

White/Green

Green/White

Blue/WhiteWhite/Blue

White/Brown

Brown/White

Ethernet Twist (hub-hub)

W/O

O/W

G/W

W/G

1

2

3

4

1

2

3

4

Hubs and Repeaters

• Hubs (Star topology)

Twisted Pair

Fiber, Coax, Twisted Pair

Backbone

(Twisted Pair may needa 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 computersTTT

Repeater Rule 10MB

• 3 repeater rule

Repeater

Repeater

Repeater

Repeater

System 1

Sys 2 Sys3

System 1 can talk to Sys 2 but not Sys3

Network Diameter (100MB)

• 205 Meter Limit

Repeater

Repeater

100M

5M

100M

10MB diameter is 500M

Switches and Bridges

Repeater

Repeater

Repeater

RepeaterB

ridge

Bridge Insides

Interface

Interface

Filter based on ethernet address

LAN A LAN B

Switch Insides

A

B

C

D

E

F

G

Switching based onethernet address

100baseT to 10baseTHub/Bridge10baseT 100baseT

10baseT hub

100baseT hub

100baseTto10baseTBridgeModule

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(switchingbased onIP address)

Firew

all

Ethernet Errors

• Carrier Loss• Collisions

– How many are tolerable?

• Jabber• Runts

– Causes

• Tools– tcpdump, snoop, traceroute, ping

Token Ring

Mic (Media Interface Connector at eachcomputer)

4 or 16 MB/s

MAU

• Multistation Access Unit

``Ring in Ring 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

AT

M S

witch

FD

DI

Concentrator

A

B

C

D

Buildings

Router

Router

Primaryrouter

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