Brocade FastIron Ethernet Switch Platform and Layer 2 Switching Configuration Guide - Manual (Page 77)

FIGURE 4 Interface IDs and types
For example, in Figure 4 , the ID of all interfaces on all nodes on Ring 1 is 1 and all interfaces on all
nodes on Ring 2 is 2. Port 1/1 on node S1 and Port 2/2 on S2 have the IDs of 1 and 2 since the
interfaces are shared by Rings 1 and 2.
The ring ID is also used to determine an interface priority. Generally, a ring ID is also the ring priority
and the priority of all interfaces on that ring. However, if the interface is shared by two or more rings,
then the highest priority (lowest ID) becomes the priority of the interface. For example, in
Figure 4 , all
interfaces on Ring 1, except for Port 1/1 on node S1 and Port 2/2 on node S2 have a priority of 1.
Likewise, all interfaces on Ring 2, except for Port 1/1 on node S1 and Port 2/2 on node S2 have a
priority of 2. Port 1/1 on S1 and Port 2/2 on S2 have a priority of 1 since 1 is the highest priority (lowest
ID) of the rings that share the interface.
If a node has interfaces that have different IDs, the interfaces that belong to the ring with the highest
priority become regular ports. Those interfaces that do not belong to the ring with the highest priority
become tunnel ports. In
Figure 4 , nodes S1 and S2 have interfaces that belong to Rings 1 and 2.
Those interfaces with a priority of 1 are regular ports. The interfaces with a priority of 2 are the tunnel
ports since they belong to Ring 2, which has a lower priority than Ring 1.
Selection of master node
Allowing MRP rings to share interfaces limits the nodes that can be designated as the master node. Any
node on an MRP ring that does not have a shared interface can be designated as the ring master node.
However, if all nodes on the ring have shared interfaces, nodes that do not have tunnel ports can be
designated as the master node of that ring. If none of the nodes meet these criteria, you must change
the rings’ priorities by reconfiguring the rings’ ID.
Selection of master node
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