User Manual

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Users Manual of XGS-6350-24X4C
through; similarly, the transit node on sub ring 2 also changes into the Preforwarding state; when the hello
packet on sub ring 1 arrives the edge node, due to the fact that the resumed transit node only allows the
control packet of the major to pass through and that the hell packet of sub ring 1 is just like the data packet of
the major ring, the hello packet cannot be forwarded.
Figure 14: Recovery of the ring’s link and the shift of the transit node to preforwarding
The transit port can transmit the control packet in preforwarding state, so the secondary port of the master
node can receive the hello packet from the primary port. Hence, the master node shifts its state to Complete,
blocks the secondary port and transmits the RING-UP-FLUSH-FDB packet from the primary port. After the
transit node receives the RING-UP-FLUSH-FDB packet, the transit node will shift back to the Link-Up state,
open the blocked port and refresh the FDB table. The procedure of ring recovery is shown in the following
figure. The master node on the major ring changes into the complete state, blocks the secondary port,
transmits the RING-UP-FLUSH-FDB packet to all transit nodes on the major ring and makes these transit
nodes to shift back to their link-up state, to open the blocked port and to refresh the FDB table; similarly, the
transit node and the master node on sub ring 2 also take on the corresponding change; due to the sub-ring
protocol packet’s channel recovery on sub ring 1, the secondary port of the master node can receive the hello
packet from the primary port, and the master node shifts its state back to the complete state, blocks the
secondary port, transmits the RING-UP-FLUSH-FDB packet and makes the assistant node open the edge
port and sub ring 1 resume to its complete state.