Topology Collection - HP A7503 Configuration Manual

IRF topology
An IRF fabric typically adopts daisy chain connection or ring connection, as shown in
• A daisy chain connection is mainly used in a network where member switches are distributedly
located.
A ring connection is more reliable than the daisy chain connection. In a daisy chained IRF fabric, the
•
failure of one link can cause the IRF fabric to partition into two independent IRF fabrics; where the
failure of a link in a ring connection result in a daisy chain connection, not affecting IRF services.
Figure 8 IRF connections
NOTE:
The ring connection is supported only when the IRF fabric has three or four member switches.

Topology collection

Each member exchanges IRF hello packets with neighbors to collect the topology data, including IRF port
connection states, member IDs, priorities, and bridge MAC addresses.
Each member is managed by its active MPU, which records its known topology information locally. At the
startup of a member switch, the active MPU of the member switch records topology information of the
member switch. When an IRF port of the member switch is up, the active MPU of the switch performs the
following operations:
Periodically sends its known topology information from this port.
1.
When receiving the topology information from the directly connected neighbor, it updates the
2.
local topology information.
If a standby MPU is available on the member switch, the active MPU synchronizes its recorded
3.
topology information to the standby MPU to ensure consistent topology information on both
boards.
After all member switches have obtained topology information (known as topology convergence), the IRF
fabric enters the role election stage.
8
Figure 7.