7
For more information about the MAD mechanisms and their application scenarios, see "
Collision handling
When MAD detects a multi-active collision, it sets all IRF fabrics except one to the Recovery state.
The fabric that is not placed in Recovery state can continue to forward traffic. The Recovery-state
IRF fabrics are inactive and cannot forward traffic.
LACP MAD uses the following process to handle a multi-active collision:
1.
Compares the number of members in each fabric.
2.
Sets all fabrics to the Recovery state except the one that has the most members.
3.
Compares the member IDs of the masters if all IRF fabrics have the same number of members.
4.
Sets all fabrics to the Recovery state except the one that has the lowest numbered master.
5.
Shuts down all physical network ports in the Recovery-state fabrics except for the following
ports:
IRF physical interfaces.
Ports you have specified with the
mad exclude interface
command.
In contrast, BFD MAD, ARP MAD, and ND MAD do not compare the number of members in fabrics.
These MAD mechanisms use the following process to hand a multi-active collision:
1.
Compare the member IDs of the masters in the IRF fabrics.
2.
Set all fabrics to the Recovery state except the one that has the lowest numbered master.
3.
Take the same action on the network ports in Recovery-state fabrics as LACP MAD.
Failure recovery
To merge two split IRF fabrics, first repair the failed IRF link and remove the IRF link failure.
•
If the IRF fabric in Recovery state fails before the failure is recovered, repair the failed IRF fabric
and the failed IRF link.
•
If the active IRF fabric fails before the failure is recovered, enable the inactive IRF fabric to take
over the active IRF fabric. Then, recover the MAD failure.
MAD mechanisms
IRF provides MAD mechanisms by extending LACP, BFD, ARP, and IPv6 ND.
IMPORTANT:
You can configure BFD MAD, ARP MAD, and ND MAD together in an IRF fabric for prompt IRF split
detection. However, do not configure any of these mechanisms together with LACP MAD, because
they handle collisions differently.
compares the MAD mechanisms and their application scenarios.
Table 1 Comparison of MAD mechanisms
MAD
mechanism
Advantages
Disadvantages
Application scenario
•
Detection speed is
fast.
•
Does not require
MAD-dedicated
physical links or
Layer 3 interfaces.
Requires an intermediate device
that supports extended LACP for
MAD.
Link aggregation is used
between the IRF fabric and
its upstream or downstream
device.
For information about LACP,
see
Layer 2—LAN Switching
Configuration Guide
.
