H3C S5500-SI Series, Руководство по эксплуатации

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while sending Common-Flush-FDB packet to instruct all the transit nodes, the edge nodes and the
assistant-edge nodes to update their own MAC entries and ARP/ND entries. After each node updates
its own entries, traffic is switched to the normal link.
Ring recovery
The master node may find the ring is restored after a period of time after the ports belonging to the
RRPP domain on the transit nodes, the edge nodes, or the assistant-edge nodes are brought up again.
A temporary loop may arise in the data VLAN during this period. As a result, broadcast storm occurs.
To prevent temporary loops, non-master nodes block them immediately (and permit only the packets of
the control VLAN to pass through) when they find their ports accessing the ring are brought up again.
The blocked ports are activated only when the nodes are sure that no loop will be brought forth by these
ports.
Broadcast storm suppression mechanism in a multi-homed subring in case of SRPT failure
As shown in Figure 1-5 , Ring 1 is the primary ring, and Ring 2 and Ring 3 are subrings. When the two
SRPTs between the edge node and the assistant-edge node are down, the master nodes of Ring 2 and
Ring 3 will open their respective secondary ports, and thus a loop among Device B, Device C, Device E,
and Device F is generated. As a result, broadcast storm occurs.
In this case, to prevent generating this loop, the edge node will block the edge port temporarily. The
blocked edge port is activated only when the edge node is sure that no loop will be brought forth when
the edge port is activated.
Load balancing
In a ring network, maybe traffic of multiple VLANs is transmitted at the same time. RRPP can implement
load balancing for the traffic by transmitting traffic of different VLANs along different paths.
By configuring an individual RRPP domain for transmitting the traffic of the specified VLANs (referred to
as protected VLANs) in a ring network, traffic of different VLANs can be transmitted according to
different topologies in the ring network. In this way, load balancing is achieved.
As shown in Figure 1-6 , Ring 1 is configured as the primary ring of Domain 1 and Domain 2, which are
configured with different protected VLANs. Device A is the master node of Ring 1 in Domain 1; Device B
is the master node of Ring 1 in Domain 2. With such configurations, traffic of different VLANs can be
transmitted on different links, and thus, load balancing is achieved in a single-ring network.
RRPP ring group
In an edge node RRPP ring group, only an activated subring with the lowest domain ID and ring ID can
send Edge-Hello packets. In an assistant-edge node RRPP ring group, any activated subring that has
received Edge-Hello packets will forward these packets to the other activated subrings. With an edge
node RRPP ring group and an assistant-edge node RRPP ring group configured, only one subring
sends 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 the
assistant-edge node of Ring 2 and Ring 3. Device B and Device C need to send or receive Edge-Hello
packets frequently. If more subrings are configured or load balancing is configured for more multiple
domains, 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 the
edge 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.