Port Mapping
Page 19-68
Who Can Talk to Whom?
The following matrix outlines which ports can communicate with each other in the example
shown on the previous page assuming all ports are part of the same group or VLAN. A port
can only communicate with ports in the opposite subset within the port mapping set.
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.
It’s important to remember that the port mapping configuration is affected by existing
group/VLAN rules. If the ports in the above example belonged to three groups based on IP
network rules, then they would be restricted by group membership and port mapping.
Port mappings can be created between switch ports and uplink ports, but not between uplink
ports. For example, you could map ethernet ports 3/1-12 to an WAN uplink port 4/1. This is
useful when there is no traffic between ethernet ports, but all ports are to be forced to the
uplink module. You cannot, however, map uplink port 4/1 to uplink port 4/2.
Port Mapping Limitations
The following are restrictions to the use of the port mapping feature:
• Port mapping cannot be used with ports assigned to an 802.1Q group.
• Port mapping cannot be used with an OmniChannel unless all ports in the OmniChannel
are included in the port mapping (on either the ingress or egress list). For example, if ports
3/1-3/4 are an OmniChannel, all four ports must be in the ingress or egress list. You could
not just map port 3/1.
Switch Ports That May Communicate*
2/1 2/4 2/5 3/1 3/4 3/5 4/1 4/4 4/5
2/1
N/A Yes Yes No Yes Yes No Yes Yes
2/4
No N/A No No No No No No No
2/5
No No N/A No No No Yes No No
3/1
No Yes Yes N/A Yes Yes No Yes Yes
3/4
No No No No N/A No No No No
3/5
No No No No No N/A No No No
4/1
No Yes Yes No Yes Yes N/A Yes Yes
4/4
Yes No No Yes No No Yes N/A No
4/5
Yes No No Yes No No Yes No N/A
*Read table from right (ingress ports) to left only.
