Get documents about "How a Token-Ring Network Works
Document Sample
246 PA R T 7 HOW THE INTERNET WORKS CHAPTER 32 HOW LOC AL AREA NETWORKS WORK 247
How a Token-Ring A
B
Network Works
CODOR
ERR
DAT
E
3
A
DA
Because the electrical resistance
TA
TO D
that’s a part of any circuit would
IN USE
gradually wipe out the token and
its attached message, each node
includes a repeater that regener-
ates the entire message to main-
D
tain the strength and integrity of
the data.
C
A
B
AVAILABLE
1 All nodes on a token-ring
network are connected to A
the same circuit, which
takes the form of a continu-
B
ous loop. A token—which
D
consists of a short all-clear
message—circulates con-
C IN USE
tinuously around a loop 4
and is read through a TO D Each node inspects the token as
it passes by to see whether the
TA
token-ring adapter card in
DA
A
token contains the node’s ad-
COD R
DAT
E
ERRO
each node as the token
passes by. dress. The node for which the
D message was intended makes a
copy of the message and then
C
DATA ATA
continues sending it along the
D ring.
A
B
DATA
ERR E
TO
DATA
COD
IN U
OR
D
SE
2 A node wanting to send a A
message grabs the token as
it passes by, changes the AVAILABLE B
binary code in the token to
say that it is in use, and at- D
taches a message, along 5 The message finally returns to the
with the address of the C originating node, which removes
node for which the mes- the message and restores the
sage is intended and error- token’s original all-clear signal.
checking code. Only one
message at a time can be
D
circulated on the network.
C
DATA ATA
D
Related docs
