Foundation Summary 201
Figure 4-32
LAN Header Formats
Dest.
Address
Preamble
T
y
p
e
Source
Address
FCS
Data
Ethernet (DIX)
8
6
6
2
Variable
4
IEEE Ethernet (802.3)
7
1
6
6
2
1
1
1-2
Variable
4
Dest.
Address
Preamble
D
S
A
P
S
S
A
P
Source
Address
FCS
Data
SD
Length
Control
802.3
802.2
802.3
7
1
6
6
2
1
1
1-2
5
Variable
4
Dest.
Address
Preamble
D
S
A
P
S
S
A
P
Source
Address
FCS
Data
SD
Length
Control SNAP
802.3
802.2
802.3
1
1
1
6
6
1
1
1-2
5
Variable
4
1
1
Dest.
Address
D
S
A
P
S
S
A
P
Source
Address
FCS
Data
AC
SD
FC
Control SNAP
ED FS
IEEE Token Ring (802.5)
1
1
1
6
6
1
1
1-2
Variable
4
1
1
Dest.
Address
D
S
A
P
S
S
A
P
Source
Address
FCS
Data
AC
SD
FC
Control
ED FS
802.5
802.2
802.5
802.2
802.5
ANSI FDDI
4
1
1
6
6
1
1
1-2
Variable
4
.5 1.5
Dest.
Address
Preamble
D
S
A
P
S
S
A
P
Source
Address
FCS
Data
SD FC
Control
ED FS
FDDI MAC
802.2
FDDI
4
1
1
6
6
1
1
1-2
5
Variable
4
.5 1.5
Dest.
Address
Preamble
D
S
A
P
S
S
A
P
Source
Address
FCS
Data
SD FC
Control SNAP
ED FS
FDDI MAC
802.2
FDDI
802.5
ch04.fm Page 201 Monday, March 20, 2000 5:02 PM