Spanning Tree | 147Basic STP CLI Port ManagementPrivileged and User Exec Mode CLI command:• Display STP settings and parameters for an interface— show spanning-tree interface unit/slot/portGlobal Config Mode CLI command:• [Disable] enable STP administrative mode for all interfaces— [no] spanning-tree port mode enable allInterface Config Mode CLI command:• [Disable] enable STP administrative mode for an interface— [no] spanning-tree port mode enableFor MSTP commands, see Multiple Spanning-Tree Protocol (MSTP, IEEE 802.1s) on page 148. Fordetails on STP commands, see the Spanning Tree chapter in the SFTOS Command Reference.Rapid Spanning Tree Protocol (RSTP, IEEE 802.1w)The default spanning tree mode in SFTOS is IEEE 802.1s (MSTP), which is backward-compatible withIEEE 802.1D and IEEE 802.1w (Rapid Spanning Tree Protocol — RSTP). SFTOS also supports RSTP asa non-default, stanalone mode. See Setting the STP Version Parameter on page 151.RSTP provides faster convergence than Spanning Tree Protocol (STP) and interoperability with otherswitches configured with STP and MSTP.RSTP ImplementationPort RolesRSTP adds new port roles to STP. Port roles that forward include:• Root Port: This is the port that is the closest to the root bridge based on path cost. A bridge sends trafficon this port to the root.• Designated Port: This is the port that is the closest to the root bridge based on path cost. A bridgereceives traffic on this port from others on the segment.Port roles that do not forward include:• Alternate Port: This is a port that is an alternate path to the root on a different bridge than thedesignated bridge.• Backup Port: This is a port that is an alternate path to the root on the designated bridge.• Disabled Port: This is a port that has no role in RSTP.
