Hirschmann RS20 Programming Manual page 55

Ring/Network coupling
Application
Disadvantage
Advantage
Table 6: Selection criteria for the variants of the redundant coupling
Note: The choice of configuration primarily depends on the topological
conditions and the desired level of security
Redundanz L2P
Release 5.0 04/09
5.1 Variants of the ring/network coupling
One-Switch coupling Two-Switch coupling Two-Switch coupling
The two devices are in
impractical topological
positions.
Therefore, putting a
line between them
would involve a lot of
work for two-Switch
coupling.
If the Switch config-
ured for the redundant
coupling fails, no con-
nection remains
between the networks.
Less work involved in
connecting the two
devices to the network
(compared with two-
Switch coupling).
The two devices are in
practical topological
positions.
Putting down a control
line would involve a lot
of work.
Much work involved in
connecting the two
devices to the network
(compared with one-
Switch coupling).
If one of the devices
configured for the re-
dundant coupling fails,
there is still a connec-
tion between the net-
works.
(see table 6).
with control line
The two devices are in
practical topological
positions.
Putting down a control
line would not involve
much work.
Much work involved in
connecting the two
devices to the network
(compared with one-
Switch and two-Switch
coupling).
If one of the devices
configured for the re-
dundant coupling fails,
there is still a connec-
tion between the net-
works.
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