Basic Principles Of Rrpp; Typical Networking Of Rrpp - H3C S7500 Series Operation Manual

Operation Mannual – RRPP
H3C S7500 Series Ethernet Switches

1.1.3 Basic Principles of RRPP

I. Link DOWN notification mechanism
When detecting a port in the RRPP domain is down, a transit node sends the LINK
DOWN packet immediately to the master node. After receiving the LINK DOWN packet,
the master node unblocks the data VLAN of the secondary port, and sends the
Common Flush packet to tell all transit nodes to refresh their respective MAC address
FDBs.
II. Polling mechanism
The primary port of the master node periodically sends the health detection packet in a
control VLAN.
If the secondary port of the master node receives the health detection packet, this
indicates that the ring link is complete, and the master node will keep the
secondary port blocked.
If the secondary port of the master node fails to receive the health detection packet
within the predefined timeout time, this indicates that a failure has occurred to the
ring link. In this case, the master node unblocks the data VLANs on the secondary
port, and sends the Common Flush packet to tell all transit nodes to refresh their
respective MAC address FDBs.
III. Ring recovery
The master node may detect that the ring has recovered a period time after the RRPP
domain port on a transit node becomes UP again. In this period, a temporary data loop
may occur in data VLANs, which can cause broadcast storm.
To avoid temporary data loops, when detecting the port through which it connects to the
ring network becomes UP again, a transit node blocks the port temporarily (only control
VLAN packets are permitted to pass), and keeps the port blocked until it receives the
Complete Flush packet from the master node.

1.1.4 Typical Networking of RRPP

To ensure normal RRPP operation, you must configure RRPP correctly. Here are
several typical networking applications.
1-5
Chapter 1 RRPP Configuration