Netgear XCM8806 Chassis Hardware Installation Guide - Page 741

NETGEAR 8800 Chassis Switch CLI Manual These encapsulation modes are for STP ports, not for physical ports. When a physical port belongs to multiple STPDs, it is associated with multiple STP ports. It is possible for the physical port to run in different modes for different domains to which it belongs. MSTP STPDs use only 802.1D BPDU encapsulation mode. The switch prevents you from configuring EMISTP or PVST+ encapsulation mode for MSTP STPDs. STP Rules and Restrictions This section summarizes the rules and restrictions for configuring STP as follows: • The carrier VLAN must span all ports of the STPD. (This is not applicable to MSTP.) • The STPD ID must be the VLAN ID of the carrier VLAN; the carrier VLAN cannot be partitioned. (This is not applicable to MSTP.) • A default VLAN cannot be partitioned. If a VLAN traverses multiple STPDs, the VLAN must be tagged. • An STPD can carry, at most, one VLAN running in PVST+ mode, and its STPD ID must be identical with that VLAN ID. In addition, the PVST+ VLAN cannot be partitioned. • The default VLAN of a PVST+ port must be identical with the native VLAN on the PVST+ device connected to that port. • If an STPD contains both PVST+ and non-PVST+ ports, that STPD must be enabled. If that STPD is disabled, the BPDUs are flooded in the format of the incoming STP port, which may be incompatible with those of the connected devices. • The 802.1D ports must be untagged; and the EMISTP/PVST+ ports must be tagged in the carrier VLAN. • An STPD with multiple VLANs must contain only VLANs that belong to the same virtual router instance. • STP and network login operate on the same port as follows: • STP (802.1D), RSTP (802.1W), and MSTP (802.1S) support both network login and STP on the same port. • At least one VLAN on the intended port should be configured both for STP and network login. • When STP blocks a port, network login does not process authentication requests and BPDUs are the only traffic in and out of the port. All user data forwarding stops. • When STP places a port in forwarding state, network login operates and BPDUs and user data flow in and out of the port. The forwarding state is the only STP state that allows network login and user data forwarding. • When RSTP is used with network login campus mode, autobind must be enabled on all VLANs that support RSTP and network login campus mode. • When RSTP is used with network login campus mode on a port, dynamic VLANs cannot be supported. • STP cannot be configured on the following ports: • A mirroring target port. Chapter 17. STP Commands | 741