1. © 2003, Cisco Systems, Inc. All rights reserved.

2. Module : LAN
Cabling & CSMA/CD

3. Objectives Describe the LAN physical layer implementations
Describe the main connectivity recommendations for implementing Ethernet in the campus
Identify different types of connectors specified for Ethernet use
Describe the different connection media for an Ethernet LAN
Describe UTP cables and connectors in an Ethernet LAN
Lesson Aim
<Enter lesson aim here.>

4. LAN Physical Layer Implementation
LLC
Sublayer
IEEE 802.2
MAC
Sublayer
Ethernet
10BASE-2
10BASE-5
10BASE-T
10BASE-F
10BASE-TX
10BASE-FX
10BASE-T4
10BASE-T
10BASE-CX
Physical
Layer
Lesson Aim
<Enter lesson aim here.>
DIX
Standard
802.3 Specifications for 10-Mbps
Ethernet
802.3u Specifications for 100-Mbps (Fast) Ethernet
802.3u Specifications for 1000-Mbps (Gigabit) Ethernet
Physical layer implementations vary.
Some implementations support multiple physical media.

5. Ethernet Connectivity Recommendations
Ethernet 10 BASE-T Positions
Fast Ethernet Position
Gigabit Ethernet Position
Provides connectivity between the end-user device and the user-level switch.
Gives high-performance PC workstations 100 Mpbs access to the servers. —
Provides connectivity between end user and workgroup. Provides connectivity from the workgroup to backbone. Provides connectivity from the server block to the backbone layer.
Lesson Aim
<Enter lesson aim here.> — —
Provides inter-switch connectivity.
Provides backbone and inter-switch connectivity. —

6. Ethernet Protocol Description
100BASE-FX
LAN speed
100 Mbps
Indicates type of cable and maximum length. If a number, maximum length = No. x 100m
Lesson Aim
<Enter lesson aim here.>
BASE = Baseband
Broad = Broadband

7. Comparing Ethernet Media Requirements10
BASE-2 10
BASE-5 10
BASE-T
100
BASE-TX
100
BASE-FX
1000
BASE-CX
1000 BASE-T
1000
BASE-SX
1000
BASE-LX
EIA/TIA Category 3, 4, 5 UTP 2 pair
EIA/TIA Category 5 UTP 2 pair
62.5/125 micro multimode fiber
EIA/TIA Category 5 UTP 4 pair
62.5/50 micro multimode fiber
9 micron single-mode fiber
50-ohm coaxial (Thinnet)
50-ohm coaxial (Thicknet)
Media
STP
Maximum Segment Length
3-10 km ( miles)
185 m ( ft)
500 m ( ft)
100 m (328 ft)
100 m (328 ft)
400 m ( ft)
25 m
(82 ft)
100 m (328 ft)
260 m (853 ft)
Lesson Aim
<Enter lesson aim here.>
Point to Point
Topology
Bus
Bus
Star
Star — — — —
Duplex media interface connector (MIC) ST
Attachment unit interface (AUI)
ISO 8877 (RJ-45)
ISO 8877 (RJ-45)
ISO 8877 (RJ-45)
ISO 8877 (RJ-45)
Connector
AUI — —

8. Differentiating Between Connections
Lesson Aim
<Enter lesson aim here.>

9. GigaStack GBIC Gigabit Interface Converters (GBICs) Lesson Aim
<Enter lesson aim here.>
Gigabit Interface Converters (GBICs)

10. Cisco WS-X2931 Gigabit Ethernet Module with GBIC Out
Lesson Aim
<Enter lesson aim here.>

11. RJ-45 Connector
Lesson Aim
<Enter lesson aim here.>

12. RJ-45 Jack
Lesson Aim
<Enter lesson aim here.>

13. UTP Implementation (Straight-Through)
Cable 10BASE-T/
100BASE-TX Straight-Through
Straight-Through Cable
Hub/Switch
Server/Router
Pin Label
Pin Label
Lesson Aim
<Enter lesson aim here.> 1 2 3 4 5 6 7 8
TX+
TX-
RX+ NC
RX- 1 2 3 4 5 6 7 8
TX+
TX-
RX+ NC
RX-
Wires on cable ends are in same order.

14. UTP Implementation (Crossover)
Cable 10BASE-T/
100BASE-TX Straight-Through
Crossover Cable
Hub/Switch
Server/Router
Pin Label
Pin Label
Lesson Aim
<Enter lesson aim here.> 1 2 3 4 5 6 7 8
TX+
TX-
RX+ NC
RX- 1 2 3 4 5 6 7 8
TX+
TX-
RX+ NC
RX-
Some wires on cable ends are crossed.

15. UTP Implementation – Straight-Through vs. Crossover
Lesson Aim
<Enter lesson aim here.>

16. Cabling the Campus Lesson Aim <Enter lesson aim here.>
1000-Mbps Category 5 Crossover
10-Mbps Category 3, 4, 5 Crossover
10-Mbps Category 3, 4, 5 Straight-Through
Lesson Aim
<Enter lesson aim here.>
10-Mbps Category 3, 4, 5 Straight-Through
100-Mbps Category 5 Straight-Through

17. Carrier sense multiple access collision detect (CSMA/CD)B C D
Carrier
Sense A B C D
Multiple
Access A B C D
Lesson Aim
<Enter lesson aim here.>
Collision
Collision A B C D
Collision
Detection
(Backoff
Algorithm)
JAM
JAM
JAM
JAM
JAM
JAM
Carrier sense multiple access collision detect (CSMA/CD)

18. CSMA/CD Process Host wants to transmit Is carrier sensed?1
Is carrier sensed?
Yes 2
Assemble frame No
Start transmitting 3
Is a collision detected?
Keep transmitting 4
Is the transmission done?
Yes
Transmission completed 5
Lesson Aim
<Enter lesson aim here.> 9
Broadcast jam signal No 6 10
Attempts = Attempts + 1
Attempts > Too many ? No No 7 11 13
Too many collisions; abort transmission
Yes
Yes
Algorithm calculates backoff 8 12 14
Wait for t microseconds

19. Summary
The three principle LAN implementation categories are Ethernet, Fast Ethernet, and Gigabit Ethernet.
There are several connection media used for Ethernet, including RJ-45, AUI, and GBIC.
A Gigabit Interface Converter (GBIC) is a hot-swappable input/output device that plugs into a Gigabit Ethernet port.
A crossover cable is used to connect between similar devices (such as switch to switch, router to router, PC to PC, and hub to hub).
A straight-through cable is used to connect between dissimilar devices (such as switch to router, switch to PC, hub to router, and hub to PC).