Dell Force10 S4820T S4820T Configuration Guide - Page 386

Ring Status, Ring Checking, Ring Failure, Ring Restoration

Page 386 highlights

www.dell.com | support.dell.com Each Transit node is also configured with a Primary port and a Secondary port on the ring, but the port distinction is ignored as long as the node is configured as a Transit node. If the ring is complete, the Master node logically blocks all data traffic in the transmit and receive directions on the Secondary port to prevent a loop. If the Master node detects a break in the ring, it unblocks its Secondary port and allows data traffic to be transmitted and received through it. Refer to the illustration below for a simple example of this FRRP topology. Note that ring direction is determined by the Master node's Primary and Secondary ports. A Virtual LAN (VLAN) is configured on all node ports in the ring. All ring ports must be members of the Member VLAN and the Control VLAN. The Member VLAN is the VLAN used to transmit data as described earlier. The Control VLAN is used to perform the health checks on the ring. The Control VLAN can always pass through all ports in the ring, including the secondary port of the Master node. Ring Status The Ring Failure notification and the Ring Status checks provide two ways to ensure the ring remains up and active in the event of a switch or port failure. Ring Checking At specified intervals, the Master Node sends a Ring Health Frame (RHF) through the ring. If the ring is complete, the frame is received on its secondary port and the Master node resets its fail-period timer and continues normal operation. If the Master node does not receive the Ring Health Frame (RHF) before the fail-period timer expires (a configurable timer), the Master node moves from the Normal state to the Ring-Fault state and unblocks its Secondary port. The Master node also clears its forwarding table and sends a control frame to all other nodes, instructing them to also clear their forwarding tables. Immediately after clearing its forwarding table, each node starts learning the new topology. Ring Failure If a Transit node detects a link down on any of its ports on the FRRP ring, it immediately sends a link-down control frame on the Control VLAN to the Master node. When the Master node receives this control frame, the Master node moves from the Normal state to the Ring-Fault state and unblocks its Secondary port. The Master node clears its routing table and sends a control frame to all other ring nodes, instructing them to clear their routing tables as well. Immediately after clearing its routing table, each node begins learning the new topology. Ring Restoration 386 | Force10 Resilient Ring Protocol (FRRP)

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386
|
Force10 Resilient Ring Protocol (FRRP)
www.dell.com | support.dell.com
Each Transit node is also configured with a Primary port and a Secondary port on the ring, but the port
distinction is ignored as long as the node is configured as a Transit node. If the ring is complete, the Master
node logically blocks all data traffic in the transmit and receive directions on the Secondary port to prevent
a loop. If the Master node detects a break in the ring, it unblocks its Secondary port and allows data traffic
to be transmitted and received through it. Refer to the illustration below for a simple example of this FRRP
topology. Note that ring direction is determined by the Master node’s Primary and Secondary ports.
A Virtual LAN (VLAN) is configured on all node ports in the ring. All ring ports must be members of the
Member VLAN and the Control VLAN.
The Member VLAN is the VLAN used to transmit data as described earlier.
The Control VLAN is used to perform the health checks on the ring. The Control VLAN can always pass
through all ports in the ring, including the secondary port of the Master node.
Ring Status
The Ring Failure notification and the Ring Status checks provide two ways to ensure the ring remains up
and active in the event of a switch or port failure.
Ring Checking
At specified intervals, the Master Node sends a Ring Health Frame (RHF) through the ring. If the ring is
complete, the frame is received on its secondary port and the Master node resets its fail-period timer and
continues normal operation.
If the Master node does not receive the Ring Health Frame (RHF) before the fail-period timer expires (a
configurable timer), the Master node moves from the Normal state to the Ring-Fault state and unblocks its
Secondary port. The Master node also clears its forwarding table and sends a control frame to all other
nodes, instructing them to also clear their forwarding tables. Immediately after clearing its forwarding
table, each node starts learning the new topology.
Ring Failure
If a Transit node detects a link down on any of its ports on the FRRP ring, it immediately sends a
link-down control frame on the Control VLAN to the Master node. When the Master node receives this
control frame, the Master node moves from the Normal state to the Ring-Fault state and unblocks its
Secondary port. The Master node clears its routing table and sends a control frame to all other ring nodes,
instructing them to clear their routing tables as well. Immediately after clearing its routing table, each node
begins learning the new topology.
Ring Restoration