Administrator Guide

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.
Important FRRP Concepts
The following table lists some important FRRP concepts.
Concept
Explanation
Ring ID Each ring has a unique 8-bit ring ID through which the ring is identified (for example, FRRP 101 and FRRP
202, as shown in the illustration in Member VLAN Spanning Two Rings Connected by One Switch.
Control VLAN Each ring has a unique Control VLAN through which tagged ring health frames (RHF) are sent. Control
VLANs are used only for sending RHF, and cannot be used for any other purpose.
Member VLAN Each ring maintains a list of member VLANs. Member VLANs must be consistent across the entire ring.
Port Role Each node has two ports for each ring: Primary and Secondary. The Master node Primary port generates
RHFs. The Master node Secondary port receives the RHFs. On Transit nodes, there is no distinction
between a Primary and Secondary interface when operating in the Normal state.
Ring Interface
State
Each interface (port) that is part of the ring maintains one of four states”
● Blocking State — Accepts ring protocol packets but blocks data packets. LLDP, FEFD, or other
Layer 2 control packets are accepted. Only the Master node Secondary port can enter this state.
● Pre-Forwarding State — A transition state before moving to the Forward state. Control traffic is
forwarded but data traffic is blocked. The Master node Secondary port transitions through this state
during ring bring-up. All ports transition through this state when a port comes up.
378 Force10 Resilient Ring Protocol (FRRP)