3Com S7906E Configuration Manual page 2155

Common port and edge port
The ports connecting the edge node and assistant-edge node to the primary ring are common ports.
The ports connecting the edge node and assistant-edge node only to the subrings are edge ports.
As shown in Figure
and Device C's Port 1 and Port 2 access the primary ring, so they are common ports. Device B's Port 3
and Device C's Port 3 access only the subring, so they are edge ports.
RRPP ring group
To reduce Edge-Hello traffic, you can configure a group of subrings on the edge node or assistant-edge
node. For information about Edge-Hello packets, refer to RRPPDUs. You must configure a device as
the edge node of these subrings, and another device as the assistant-edge node of these subrings.
Additionally, the subrings of the edge node and assistant-edge node must connect to the same subring
packet tunnels in major ring (SRPTs), so that Edge-Hello packets of the edge node of these subrings
travel to the assistant-edge node of these subrings over the same link.
An RRPP ring group configured on the edge node is called an edge node RRPP ring group, and an
RRPP ring group configured on an assistant-edge node is called an assistant-edge node RRPP ring
group. Up to one subring in an edge node RRPP ring group is allowed to send Edge-Hello packets.
RRPPDUs
Table 1-1 shows the types of RRPPDUs and their functions.
Table 1-1 RRPPDU types and their functions
Type
Hello
Fast-Hello
Link-Down
Common-Flush-FDB
Complete-Flush-FDB
Edge-Hello
Fast-Edge-Hello
Major-Fault
1-1, Device B and Device C lie on Ring 1 and Ring 2. Device B's Port 1 and Port 2
The master node initiates Hello packets to detect the integrity of a ring in a
network.
The master node initiates Fast-Hello packets to fast detect the integrity of a
ring in a network.
The transit node, the edge node or the assistant-edge node initiates
Link-Down packets to notify the master node of the disappearance of a ring
in case of a link failure.
The master node initiates Common-Flush-FDB (FDB stands for Forwarding
Database) packets to instruct the transit nodes to update their own MAC
entries and ARP/ND entries when an RRPP ring transits to Disconnect
state.
The master node initiates Complete-Flush-FDB packets to instruct the
transit nodes to update their own MAC entries and ARP/ND entries, and
release blocked ports from being blocked temporarily when an RRPP ring
transits to Health state.
The edge node initiates Edge-Hello packets to examine the SRPTs
between the edge node and the assistant-edge node.
The edge node initiates Fast-Edge-Hello packets to fast examine the
SRPTs between it and the assistant-edge node.
The assistant-edge node initiates Major-Fault packets to notify the edge
node of SRPT failure when an SRPT between edge node and
assistant-edge node is torn down.
Description
1-4