Collision handling, Failure recovery, Mad mechanisms – H3C Technologies H3C SecPath F5020 User Manual
Page 19: Mechanisms
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Collision handling
MAD mechanisms remove multi-active collisions by setting one IRF fabric to the Detect state and other IRF
fabrics to the Recovery state. The Detect-state IRF fabric is active. The Recovery-state IRF fabric is inactive.
Only members in the Detect-state fabric can continue to forward traffic.
BFD MAD uses the following process to handle a multi-active collision:
All MAD mechanisms use the following process to handle a multi-active collision:
1.
Compares the member IDs of masters in each fabric.
2.
Sets the IRF fabric that has the lowest numbered master to the Detect state, and all other fabrics to
the Recovery (disabled) state.
3.
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.
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
You can configure a minimum of one MAD mechanism on an IRF fabric for prompt IRF split detection.
compares the MAD mechanisms and their application scenarios.
Table 1 Comparison of MAD mechanisms
MAD
mechanism
Advantages Disadvantages
Application
scenario
•
Detection speed is fast.
•
No intermediate device is
required.
•
Intermediate device, if used,
can come from any vendor.
•
Requires MAD dedicated
physical links and Layer 3
interfaces, which cannot
be used for transmitting
user traffic.
•
If no intermediate device
is used, the IRF members
must be fully meshed.
•
If an intermediate device
is used, every IRF
member must connect to
the intermediate device.
•
No special
requirements for
network scenarios.
•
If no intermediate
device is used, this
mechanism is only
suitable for IRF fabrics
that have members
that are
geographically close
to one another.
For information about
BFD, see High
Availability
Configuration Guide.