54 
Primary port and secondary port 
Each master node or transit node has two ports connected to an RRPP ring, one serving as the primary 
port and the other serving as the secondary port. You can determine the port’s role.  
1.  In terms of functionality, the primary port and the secondary port of a master node have the 
following differences: 
{  The primary port and the secondary port are designed to play the role of sending and 
receiving loop-detect packets respectively. 
{  When an RRPP ring is in Health state, the secondary port of the master node will logically deny 
data VLANs and permit only the packets of the control VLANs.  
{  When an RRPP ring is in Disconnect state, the secondary port of the master node will permit 
data VLANs (forward packets of data VLANs). 
2.  In terms of functionality, the primary port and the secondary port of a transit node have no 
difference. Both are designed for transferring protocol packets and data packets over an RRPP 
ring.  
As shown in Figure 11, D
evice A is the master node of Ring 1. Port 1 and Port 2 are the primary port and 
the secondary port of the master node on Ring 1 respectively. Device B, Device C, and Device D are the 
transit nodes of Ring 1. Their Port 1 and Port 2 are the primary port and the secondary port on Ring 1 
respectively.  
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 11, D
evice B and Device C lie on Ring 1 and Ring 2. Device B’s Port 1 and Port 2 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 more information about Edge-Hello packets, see "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 an edge node RRPP ring group, and an RRPP ring 
group configured on an assistant-edge node is 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 18 RRPPDU types and their functions 
T
e Descri
tion
Hello 
The master node initiates Hello packets to detect the integrity of a ring in a 
network. 
Link-Down 
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.