Wired LANS - Ethernet and Computer Local Area Networks

Software Engineering Departments
COE (College of Engineering
8.1
Lecture 8
Wired LANs: Ethernet
Computer Communication and Networks
Engr. Farhan Ghafoor

Figure 13.1 IEEE standard for LANs

Figure 13.2 HDLC frame compared with LLC and MAC frames

13--22 STANDARD ETHERNET
The original Ethernet was created in 1976 at Xerox’s
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Topics discussed in this section:
MAC Sublayer
Physical Layer

Figure 13.3 Ethernet evolution through four generations

Figure 13.5 Minimum and maximum lengths

Note
Frame length:
Minimum: 64 bytes (512 bits)
Maximum: 1518 bytes (12,144 bits)
13.8

Figure 13.6 Example of an Ethernet address in hexadecimal notation
13.9

Figure 13.7 Unicast and multicast addresses
13.10

Note
The least significant bit of the first byte
defines the type of address.
If the bit is 0, the address is unicast;
otherwise, it is multicast.
13.11

Note
The broadcast destination address is a
special case of the multicast address in
which all bits are 1s.
13.12

Example 13.1
Define the type of the following destination addresses:
b 47:20:1B:2E:08:EE
a 4A:30:10:21:10:1
c. FF:FF:FF:FF:FF:FF
Solution
13.13
To find the type of the address, we need to look at the
second hexadecimal digit from the left. If it is even, the
address is unicast. If it is odd, the address is multicast. If
all digits are F’s, the address is broadcast. Therefore, we
have the following:
a. This is a unicast address because A in binary is1010.
b. This is a multicast address because 7 in binary is 0111.
c. This is a broadcast address because all digits are F’s.

Example 13.2
Show how the address 47:20:1B:2E:08:EE is sent out on
line.
Solution
The address is sent left-to-right, byte by byte; for each
byte, it is sent right-to-left, bit by bit, as shown below:
13.14

Figure 13.8 Categories of Standard Ethernet
13.15

Figure 13.9 Encoding in a Standard Ethernet implementation
13.16

Figure 13.10 10Base5 implementation
13.17

Figure 13.11 10Base2 implementation
13.18

Figure 13.12 10Base-T implementation
13.19

Figure 13.13 10Base-F implementation
13.20

Table 13.1 Summary of Standard Ethernet implementations
13.21

13--33 CHANGES IN THE STANDARD
The 10-Mbps Standard Ethernet has gone through
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These changes aacctually opened the road to the
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Bridged Ethernet
Switched Ethernet
Full-Duplex Ethernet
13.22

Figure 13.14 Sharing bandwidth
13.23

Figure 13.15 A network with and without a bridge
13.24

Figure 13.16 Collision domains in an unbridged network and a bridged network
13.25

Figure 13.17 Switched Ethernet
13.26

Figure 13.18 Full-duplex switched Ethernet
13.27

13--44 FAST ETHERNET
Fast Ethernet was designed to compete with LAN
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Fast Ethernet under the name 802..3u.. Fast Ethernet
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MAC Sublayer
Physical Layer
13.28

Figure 13.19 Fast Ethernet topology
13.29

Figure 13.20 Fast Ethernet implementations
13.30

Figure 13.21 Encoding for Fast Ethernet implementation
13.31

Table 13.2 Summary of Fast Ethernet implementations
13.32

13--55 GIGABIT ETHERNET
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13.33
MAC Sublayer
Physical Layer
Ten-Gigabit Ethernet

Note
In the full-duplex mode of Gigabit
Ethernet, there is no collision;
the maximum length of the cable is
determined by the signal attenuation
in the cable.
13.34

Figure 13.22 Topologies of Gigabit Ethernet
13.35

Figure 13.23 Gigabit Ethernet implementations
13.36

Figure 13.24 Encoding in Gigabit Ethernet implementations
13.37

Table 13.3 Summary of Gigabit Ethernet implementations
13.38

Table 13.4 Summary of Ten-Gigabit Ethernet implementations
13.39

Wired LANS - Ethernet and Computer Local Area Networks

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