HPE FlexFabric 12900E Series Configuration Manual page 8

IRF physical interface
IRF physical interfaces connect IRF member devices and must be bound to an IRF port. They
forward traffic between member devices, including IRF protocol packets and data packets that must
travel across IRF member devices.
IRF split
IRF split occurs when an IRF fabric breaks up into multiple IRF fabrics because of IRF link failures,
as shown in
routing and forwarding problems on the network. To quickly detect a multi-active collision, configure
a minimum of one MAD mechanism (see
Figure 3 IRF split
Device A
IRF merge
IRF merge occurs when two split IRF fabrics reunite or when two independent IRF fabrics are united,
as shown in
Figure 4 IRF merge
IRF fabric 1
Device A
MAD
An IRF link failure causes an IRF fabric to split in two IRF fabrics operating with the same Layer 3
settings, including the same IP address. To avoid IP address collision and network problems, IRF
uses multi-active detection (MAD) mechanisms to detect the presence of multiple identical IRF
fabrics, handle collisions, and recover from faults.
IRF domain ID
One IRF fabric forms one IRF domain. IRF uses IRF domain IDs to uniquely identify IRF fabrics and
prevent IRF fabrics from interfering with one another.
As shown in
C and Device D. Both fabrics use the LACP aggregate links between them for MAD. When a
member device receives an extended LACPDU for MAD, it checks the domain ID to determine
whether the packet is from the local IRF fabric. Then, the member device can handle the packet
correctly.
Figure 3. The split IRF fabrics operate with the same IP address. IRF split causes
IRF fabric
IRF link
Device B
Figure 4.
IRF fabric 2
+
Device B
Figure 5, IRF fabric 1 contains Device A and Device B, and IRF fabric 2 contains Device
"Configuring MAD").
IRF fabric 1
=
Device A
=
Device A
4
IRF fabric 2
+
Device B
IRF fabric
IRF link
Device B