AMX NXA-ENET8-2POE Operation/Reference Manual page 106

Configuring the NXA-ENET8-2POE
STP/RSTP/CIST Port Configuration parameters (Cont.)
• Path Cost
• Priority
• Admin Edge (Fast
Forwarding)
• Auto Edge
• Restricted Role
• Restricted TCN
• BPDU Guard
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This parameter is used by the STA to determine the best path between devices.
Therefore, lower values should be assigned to ports attached to faster media, and
higher values assigned to ports with slower media. (Path cost takes precedence
over port priority.)
By default, the system automatically detects the speed and duplex mode used on
each port, and configures the path cost according to the values shown in the Path
Costs table on page 97.
Defines the priority used for this port in the Spanning Tree Algorithm. If the path
cost for all ports on a switch are the same, the port with the highest priority (i.e.,
lowest value) will be configured as an active link in the Spanning Tree. This makes
a port with higher priority less likely to be blocked if the Spanning Tree Algorithm is
detecting network loops. Where more than one port is assigned the highest prior-
ity, the port with lowest numeric identifier will be enabled. (Range: 0-240, in steps
of 16; Default: 128)
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 for-
warding loops, they can pass directly through to the spanning tree forwarding
state.
Specifying edge ports provides quicker convergence for devices such as worksta-
tions 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. How-
ever, remember that this feature should only be enabled for ports connected to an
endnode device. (Default: 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)
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 pre-
vent 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.
If enabled, this causes the port not to propagate received topology change notifi-
cations and topology changes to other ports. TCN messages can cause tempo-
rary 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.
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 120).
NXA-ENET8-2POE Gigabit Ethernet Layer 2 PoE Switch