SMC Networks SMCGS10C-SMART Management Manual page 127

detecting network loops. Where more than one port is assigned the
highest priority, the port with lowest numeric identifier will be enabled.
(Range: 0-240, in steps of 16; Default: 128)
Admin Edge (Fast Forwarding) – You can enable this option if an
◆
interface is attached to a LAN segment that is at the end of a bridged
LAN or to an end node. Since end nodes cannot cause forwarding loops,
they can pass directly through to the spanning tree forwarding state.
Specifying edge ports provides quicker convergence for devices such as
workstations or servers, retains the current forwarding database to
reduce the amount of frame flooding required to rebuild address tables
during reconfiguration events, does not cause the spanning tree to
initiate reconfiguration when the interface changes state, and also
overcomes other STA-related timeout problems. However, remember
that this feature should only be enabled for ports connected to an end-
node device. (Default: Edge)
Auto Edge – Controls whether automatic edge detection is enabled on
◆
a bridge port. When enabled, the bridge can determine that a port is at
the edge of the network if no BPDU's are received on the port.
(Default: Enabled)
Restricted Role – If enabled, this causes the port not to be selected
◆
as Root Port for the CIST or any MSTI, even if it has the best spanning
tree priority. Such a port will be selected as an Alternate Port after the
Root Port has been selected. If set, this can cause a lack of spanning
tree connectivity. It can be set by a network administrator to prevent
bridges external to a core region of the network influencing the
spanning tree active topology, possibly because those bridges are not
under the full control of the administrator. This feature is also know as
Root Guard.
Restricted TCN – If enabled, this causes the port not to propagate
◆
received topology change notifications and topology changes to other
ports. TCN messages can cause temporary loss of connectivity after
changes in a spanning tree's active topology as a result of persistent
incorrectly learned station location information. TCN messages can be
restricted by a network administrator to prevent bridges external to a
core region of the network from causing address flushing in that region,
possibly because those bridges are not under the full control of the
administrator or the physical link state for the attached LANs transitions
frequently.
BPDU Guard – This feature protects ports from receiving BPDUs. It
◆
can prevent loops by shutting down an port when a BPDU is received
instead of putting it into the spanning tree discarding state. The BPDU
guard feature provides a secure response to invalid configurations
because an administrator must manually enable the port.
(Default: Disabled)
If enabled, the port will disable itself upon receiving valid BPDU's.
Contrary to the similar bridge setting, the port Edge status does not
affect this setting. A port entering error-disabled state due to this
setting is subject to the bridge Port Error Recovery setting as well (see
"Configuring Global Settings for STA" on page
– 127 –
| Configuring the Switch
C 4
HAPTER
Configuring the Spanning Tree Algorithm
118).