Flow When A Link Breaks; Configuring Mrp With Shared Interfaces - Dell PowerConnect B-RX Configuration Manual

Flow when a link breaks

If the link between shared interfaces breaks
master node changes to a preforwarding state. The RHP packet sent by port 3/1 on Ring 2 is
forwarded through the interfaces on S4, then to S2. The packet is then forwarded through S2 to S3,
but not from S2 to S1 since the link between the two nodes is not available. When the packet
reaches Ring 1's master node, the packet is forwarded through the secondary interface since it is
currently in a preforwarding state. A secondary interface in preforwarding mode ignores any RHP
packet that is not from its ring. The secondary interface changes to blocking mode only when the
RHP packet forwarded by its primary interface is returned.
The packet then continues around Ring 1, through the interfaces on S1 to Ring 2 until it reaches
Ring 2's master node. Port 3/2, the secondary interface on Ring 2 changes to blocking mode since
it received its own packet, then blocks the packet to prevent a loop.
FIGURE 74
RHP packets follow this flow until the link is restored; then the RHP packet returns to it normal flow
as shown in
NOTE
There should always be a layer 2 protocol configured in the default VLAN when MRP is configured
with all dual mode ports.

Configuring MRP with shared interfaces

MRP Phase 2 allows you to enter commands such as the following when configuring MRP.
BigIron RX Series Configuration Guide
53-1002253-01
Flow of RHP packets when a link for shared interfaces brakes
port2/2 changes
to preforwarding
1
Master node
(primary interface) port2/1
1
= Ring 2 RHP packet
Figure 74.
Ring initialization for shared interfaces
(Figure 74), the secondary interface on Ring 1's
2
1
1
T
2
1
S1
1,2
X
Ring 1
Ring 2
1,2
S2
1 2
T
1
1 2
S4
S3
2
2
port3/2
Master node
port3/1 (primary interface)
2
2
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