Port Mapping
Page 19-67
Port communication is uni-directional. A mapping between an ingress port and an egress port
can only pass data from the ingress port to the egress port. To allow traffic to flow the from
the egress port to the ingress port, it is necessary to create a new mapping.
This configuration restricts each port to communication only with the other four ports in the
opposite port mapping subset within the same group. For example, port 2/1 can only send traf-
fic to ports 5/1, 5/2, 5/3, and 5/4. It can no longer communicate with ports 2/2, 2/3, and 2/4
even though they are part of the same group. Port mapping restricts ports from communicat-
ing with other ports within the same subset.
Port mapping does not affect other ports in the group that are not part of the port mapping
set.

The Details of Port Mapping

Port mapping can be thought of as special rule that is applied after standard group and VLAN
rules are applied. This rule statically assigns a port as either an ingress or egress port. Ingress
ports can only communicate with egress ports. In this sense, one subset of ports is “mapped”
to another subset of ports. Ports within the same subset can not communicate with each other
or with another switch port that is not a member of the opposite port mapping subset.
♦ Note ♦
Port mapping restrictions are only applied to ports on
10/100 Ethernet modules (e.g., ESM-100F-8, ESM-C-32,
ESM-FM-16W, ESM-100C-12).
As an illustration, see the diagram of three Ethernet modules below. The modules are in slots
2, 3, and 4. The ports that are circled are included in a port mapping subset. The three ports
at the top—2/1, 3/1, and 4/1—are ingress ports. The six ports below —2/4, 2/5, 3/4, 3/5, 4/4,
and 4/5—are egress ports in the port mapping set.
Port Subsets in the Port Mapping Set
1x
6x
2x
3x
4x
5x
7x
8x
6
7
12
8
9
10
11
LNK
ACT 1x
6x
2x
3x
4x
5x
7x
8x
6
7
12
8
9
10
11
LNK
ACT 1x
6x
2x
3x
4x
5x
7x
8x
6
7
12
8
9
10
11
LNK
ACT

Slot 2

Slot 3

Slot 4

One side of the
paired set. Ports
2/1, 3/1, and 4/1.
These ports are
subset A.
Other side of the
paired set. Ports
2/4, 2/5, 3/4, 3/5,
4/4, and 4/5.
These ports are
subset B.