The applications with SEP protection are diverse, as we saw in:
Hybrid SEP+MSTP Ring Networking
Hybrid SEP+RRPP Ring Networking
The SEP application with multi-instance follows.
As shown in Figure 1, SEP multi-instance allows two SEP segments to be configured on one physical ring network. All devices, interface roles, and control VLANs in each SEP segment must be configured by conforming to basic SEP configurations principles. Each SEP segment has one blocked interface. Each blocked interface detects whether the physical ring network is complete. The blocked interfaces in the two SEP segments are independent of each other.
Each SEP segment needs to be configured with a protected instance and each protected instance represents a VLAN range. The topology calculated by a SEP segment is valid only for that SEP segment.
After different protected instances are configured for SEP segments and the mapping between protected instances and VLANs is set, a blocked interface is valid only for the VLANs protected by the SEP segment where the blocked interface resides. Data traffic of different VLANs can be transmitted along different paths. This implements traffic load balancing and link backup.
Figure 1 Networking diagram for SEP multi-instance
