1-7node RRPP ring group and an assistant-edge node RRPP ring group configured, only one subringsends and receives Edge-Hello packets, thus reducing CPU workload.As shown in Figure 1-5, Device B is the edge node of Ring 2 and Ring 3, and Device C is theassistant-edge node of Ring 2 and Ring 3. Device B and Device C need to send or receive Edge-Hellopackets frequently. If more subrings are configured or load balancing is configured for more multipledomains, Device B and Device C will send or receive a mass of Edge-Hello packets.To reduce Edge-Hello traffic, you can assign Ring 2 and Ring 3 to an RRPP ring group configured on theedge node Device B, and assign Ring 2 and Ring 3 to an RRPP ring group configured on Device C.After such configurations, if all rings are activated, only Ring 2 on Device B sends Edge-Hello packets.Fast detection mechanismIdeally, an RRPP ring can fast converge because the transit nodes on it can detect link failures fast andsend out notifications immediately. In practice, however, some devices on an RRPP ring may notsupport RRPP and thus RRPP can detect link failures between these devices only through the timeoutmechanism. This results in long-time traffic interruption and failure to implement millisecond-levelconvergence.To address this problem, a fast detection mechanism was introduced. The mechanism works as follows:z The master node sends Fast-Hello packets out its primary port at the interval specified by theFast-Hello timer. If the secondary port receives the Fast-Hello packets sent by the local masternode before the Fast-Fail timer expires, the entire ring is in Health state; otherwise, the ring transitsinto Disconnect state.z The edge node sends Fast-Edge-Hello packets out its common ports at the interval specified bythe timer resolution. If the assistant-edge node fails to receive the Fast-Edge-Hello packets withinthree times the timer resolution, the SRPTs transit to Disconnect state.As shown in Figure 1-2, with fast detection enabled for RRPP domain 1, Device A, the master node ofRing 1, sends out Fast-Hello packets periodically and determines the ring status according to whetherFast-Hello packets are received before the Fast-Fail timer expires, thus implementing link status fastdetection.z The timer resolution refers to the shortest-period timer provided on an RRPP node.z To implement fast detection on an RRPP ring, enable fast detection on the master node, edgenode, and assistant-edge node of the RRPP ring.Typical RRPP NetworkingHere are several typical networking applications.Single ringAs shown in Figure 1-2, there is only a single ring in the network topology. In this case, you only need todefine an RRPP domain.
