Operating Mechanism Of Smart Link; Smart Link Configuration Task List - H3C S5810 Series Operation Manual

Operating Mechanism of Smart Link

Link backup mechanism
As shown in Figure
Device C is the standby link. Normally, GE1/0/1 is in the forwarding state, while GE1/0/2 is in the
standby state. When the link on GE1/0/1 fails, GE1/0/2 takes over to forward traffic while GE1/0/1 is
blocked and placed in the standby state.
When a port switches to the forwarding state, the system outputs log information to notify the user of the
port state change.
As link switchover can outdate the MAC address forwarding entries and ARP/ND entries on all devices,
you need a forwarding entry update mechanism to ensure proper transmission. By far, the following two
update mechanisms are provided:
Uplink traffic-triggered MAC address learning, where update is triggered by uplink traffic. This
mechanism is applicable to environments with devices not supporting smart link, including devices
of other vendors'.
Flush update where a Smart Link-enabled device updates its information by transmitting flush
messages over the backup link to its upstream devices. This mechanism requires the upstream
devices to be capable of recognizing smart link flush messages to update its MAC address
forwarding entries and ARP/ND entries.
To keep traffic forwarding stable, the master port that has been blocked due to link failure does not take
over immediately upon its recovery. Instead, link switchover will occur at next link switchover.
Role preemption mechanism
As shown in Figure
Device C is the standby link. Once GE1/0/1 fails, GE1/0/2 takes over to forward traffic. During this
period, if the smart link group is configured with role preemption, GE1/0/1 takes over to forward traffic as
soon as it recovers.
Load sharing mechanism
A ring network may carry traffic of multiple VLANs. Smart link can forward traffic of different VLANs in
different smart link groups, thus implementing load sharing.
To implement load sharing, you can assign a port to multiple smart link groups (each configured with
different protected VLANs), making sure that the state of the port is different in these smart link groups.
In this way, traffic of different VLANs can be forwarded along different paths.
You can configure protected VLANs for a smart link group by referencing MSTIs.

Smart Link Configuration Task List

Complete the following tasks to configure Smart Link:
Configuring a Smart
Link Device
1-1, the link on GE1/0/1 of Device C is the active link, and the link on GE1/0/2 of
1-1, the link on GE1/0/1 of Device C is the active link, and the link on GE1/0/2 of
Task
Configuring Protected VLANs for a Smart Link Group
Configuring Member Ports for a Smart Link Group
Configuring Role Preemption for a Smart Link Group
Enabling the Sending of Flush Messages
1-4
Remarks
Required
Required
Optional
Optional