An RSTP link type classifies a switch link and determines how its ports transition to forwarding and respond to topology changes. RSTP defines point-to-point, shared, and edge links. section 15.3
The three link types behave differently:
- Point-to-point: A full-duplex link that can use RSTP synchronization to transition rapidly to forwarding. Cisco switches identify full-duplex ports automatically, or you can configure spanning-tree link-type point-to-point. section 15.3
- Shared: A half-duplex link, such as a connection through a hub, that cannot use synchronization and transitions like standard STP, taking 30 seconds to reach forwarding. section 15.3
- Edge: A port connected to an end host that uses PortFast to transition immediately to forwarding because no Layer 2 loop is expected. section 15.3
Recognizing link types
A show spanning-tree listing may display Shr for a shared link, P2p for a point-to-point link, and P2p Edge for a full-duplex point-to-point link using PortFast.
