Coupling topology shows a coupling topology, in which adjacent rings share two switches
in common. A primary port is on one switch, and a backup port is on another switch.
Coupling topology
Dual homing topology
shows a dual homing topology, in which adjacent rings share a single switch in common.
Both primary port and backup port are on the shared switch.
Dual homing topology
Ring - Each switch can be master or slave.
Coupling and dual homing - Each switch can be
primary, backup, or both.
When the switch's role is
coupling/primary, only one ring port, the primary port, needs to be configured.
When the switch's role is
coupling/backup, only one ring port, the backup port, needs to be configured. The
backup port is a redundant port. In normal state, it is blocked.
When the switch's role is
dual-homing, one ring port is the primary port and another is the backup port. The
backup port is a redundant port. In normal state, it is blocked.
