H3C MSR 5600, Configuration Manual, Page: 16 / 46

9
Figure 8 Active IRF fabric fails before the IRF link is recovered
MAD mechanisms
IRF provides MAD mechanisms by extending LACP and BFD.
Table 1 compares the MAD mechanisms and their application scenarios.
Table 1 Comparison of MAD mechanisms
MAD
mechanism
Advantages Disadvantages
Application
scenarios
LACP MAD
•
Detection speed is fast.
•
Runs on existing
aggregate links without
requiring 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.
BFD MAD
•
Detection speed is fast.
•
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. The MSR routers
support Layer 3 aggregate
interfaces for BFD MAD and
the interfaces must operate
in static aggregation mode.
•
No special
requirements for
network scenarios.
•
If no intermediate
device is used, this
mechanism is only
suitable for IRF
fabrics that have
only two members
IRF
fabric 1
(Active)
IRF fabric 2
(Recovery)
IP network
IP network
IRF fabric 2
(Recovery)
IP network
IP network
IRF fabric 1
fails before
the IRF link
is recovered.
IRF fabric 1
fails
because of
physical
problems
IRF fabric 2
(Active)
IP network
IP network
IRF fabric 1
fails
because of
physical
problems
IRF
fabric
IP network
IP network
Repair the
IRF link and
IRF fabric 1,
and finish
IRF merge
Execute the mad
restore command
on IRF fabric 2