Enhancements
Release M.10.37 Enhancements
[root-guard]
MSTP only. When a port is enabled as root-guard, it cannot be selected as the root port even if it receives superior STP BPDUs. The port is assigned an “alternate” port role and enters a blocking state if it receives superior STP BPDUs. The BPDUs received on a root-guardport are ignored. All other BPDUs are accepted and the external devices may belong to the spanning tree as long as they do not claim to be the Root device. (Default: No - disabled)
Note: In standard Spanning Tree Protocol operation, the calculation of active network topologies may be an issue when switches outside the core region of a network are under shared or limited administrative control. Such a switch may become a Root Bridge for the entire network and create non-optimal forwarding paths. By enabling the root-guardfeature on ports that face outside the core network, external boundaries for the core network are created to ensure the Root Bridge is located within the core network.
[tcn-guard]
When tcn-guardis enabled for a port, it causes the port to stop propagating received topology change notifications and topology changes to other ports. (Default: No - disabled)
Syntax: spanning-tree < port-list> < hello-time path-cost point-to-point-mac priority > [ hello-time < global 1 - 10 >
When the switch is the CIST root, this parameter specifies the interval (in seconds) between periodic BPDU transmissions by the designated ports. This interval also applies to all ports in all switches downstream from each port in the < port-list>. A setting of global indicates that the ports in < port-list> on the CIST root are using the value set by the global spanning-tree hello-timevalue. When a given switch “X” is not the CIST root, the per-port hello-timefor all active ports on switch “X” is propagated from the CIST root, and is the same as the hello-timein use on the CIST root port in the currently active path from switch “X” to the CIST root. (That is, when switch “X” is not the CIST root, then the upstream CIST root’s port hello-timesetting overrides the hello-timesetting configured on switch “X”. (Default Per-Port setting: Use Global. Default Global Hello-Time: 2.)
[ path-cost < auto 1..200000000 > ]
Assigns an individual port cost that the switch uses to determine which ports are forwarding ports in a given spanning tree. In the default configuration (auto) the switch determines a port’s path cost by the port’s type:
–10 Mbps: 2000000
–100 Mbps: 200000
–1 Gbps: 20000