Users Guide
Member VLAN Spanning Two Rings Connected by One Switch
A member VLAN can span two rings interconnected by a common switch, in a figure-eight style topology.
A switch can act as a Master node for one FRRP group and a Transit for another FRRP group, or it can be a Transit node for
both rings.
In the following example, FRRP 101 is a ring with its own Control VLAN, and FRRP 202 has its own Control VLAN running on
another ring. A Member VLAN that spans both rings is added as a Member VLAN to both FRRP groups. Switch R3 has two
instances of FRRP running on it: one for each ring. The example topology that follows shows R3 assuming the role of a Transit
node for both FRRP 101 and FRRP 202.
Important FRRP Points
FRRP provides a convergence time that can generally range between 150ms and 1500ms for Layer 2 networks.
The Master node originates a high-speed frame that circulates around the ring. This frame, appropriately, sets up or breaks
down the ring.
• The Master node transmits ring status check frames at specified intervals.
• You can run multiple physical rings on the same switch.
• One Master node per ring — all other nodes are Transit.
• Each node has two member interfaces — primary and secondary.
• There is no limit to the number of nodes on a ring.
• Master node ring port states — blocking, pre-forwarding, forwarding, and disabled.
• Transit node ring port states — blocking, pre-forwarding, forwarding, and disabled.
• STP disabled on ring interfaces.
• Master node secondary port is in blocking state during Normal operation.
• Ring health frames (RHF)
– Hello RHF: sent at 500ms (hello interval); Only the Master node transmits and processes these.
– Topology Change RHF: triggered updates; processed at all nodes.
Implementing FRRP
• FRRP is media and speed independent.
• FRRP is a Dell proprietary protocol that does not interoperate with any other vendor.
• You must disable the spanning tree protocol (STP) on both the Primary and Secondary interfaces before you can enable
FRRP.
• All ring ports must be Layer 2 ports. This is required for both Master and Transit nodes.
• A VLAN configured as a control VLAN for a ring cannot be configured as a control or member VLAN for any other ring.
• The control VLAN is not used to carry any data traffic; it carries only RHFs.
• The control VLAN cannot have members that are not ring ports.
• If multiple rings share one or more member VLANs, they cannot share any links between them.
• Member VLANs across multiple rings are not supported in Master nodes.
• Each ring has only one Master node; all others are transit nodes.
Attention: The port extender does not support FRRP.
Force10 Resilient Ring Protocol (FRRP) 380