Topology Collection; Role Election - HP 4800G Series Configuration Manual

Figure 1-7 Correspondence in aggregate mode for two interface modules
Because the two physical IRF ports bound to an aggregate IRF port must be located on the same
interface module, two IRF ports (that is, two aggregate IRF ports) can only be bound to the two physical
IRF ports on each of the two interface modules respectively (as shown in
can only bind IRF-port 1 to physical IRF ports 1 and 2, and IRF-port 2 to physical ports 3 and 4.
If one dual-port interface module and one single-port interface module are installed, you can bind two
physical IRF ports on the dual-port interface module to the IRF port in aggregate mode, and bind the
physical IRF port on the single-port interface module to the other IRF port in non-aggregate mode. In
this situation, IRF-port 2 or IRF-port 1 can be bound to any physical port on the device, because only
one IRF port is needed on Switch B or Switch C.

Topology Collection

Each device in an IRF exchanges hello packets with the directly connected neighbors to collect
topology of the entire IRF. The hello packets carry topology information, including IRF port connection
states, member IDs, priorities, and bridge MAC addresses.
Each member records its known topology information locally. At the initiation of the collection, the
members record their own topology information. When an IRF port of a member becomes up, the
member sends its known topology information from this port periodically. Upon receiving the topology
information, the directly connected neighbor updates the local topology information.
The collection process lasts for a period of time. When all members have obtained the complete
topology information (known as topology convergence), the IRF will enter the next stage: role election.

Role Election

An IRF is composed of multiple member devices; each member has a role, which is either master or
slave. The process of defining the role of IRF members is role election.
Role election is held when the topology is instable, such as, forming an IRF, adding a new member, IRF
split, or IRF merge. The master is elected according to the following principles one by one, until the only
winner is found out:
1-7
Figure 1-7). In addition, you