Foundry NetIron M2404C and M2404F Metro Access Switches
Configuring MSTP (Rev. 03)
Overview
© 2008 Foundry Networks, Inc
Page 33 of 70
administrative state variable according to the port’s knowledge of whether or not any BPDUs
have been received on the Port.
•
EdgePort
The Bridge Detection state machine controls the value of the corresponding operational state
variable, operational EdgePort, which may be used in order to determine whether a port that
becomes Designated is permitted to transit directly to Forwarding. A value of enabled in the
show commands indicates that this state transition is permitted to occur.
If a BPDU is received on the Port, then the value of operational EdgePort is set to disabled.
Following a port initialization, or following a link-up event, operational EdgePort is set to the
value of admin EdgePort.
Hence, if a Port that has been marked as an edge-port proves not to be one (due to the presence
of another Bridge), then it will cease to behave like an edge-port until such a time as it is
reinitialized (either by a link up/down event or by reissuing the CLI command).
NOTE
If a BPDU is received on a port defined as an edge port, it automatically reverts to
edge-port disabled
status. After link up/down or after the edge port command is
used, the port returns to the Admin status.
You can use the
flush-port
option to force MSTP to flush the edge port on which the option is
configured, when the link on that port goes down. The MSTP Edge Port should be used if neither
the device connected to the port nor the network connected to this device is enabled with MSTP
(an MSTP edge port must be configured only if there is no possibility that BPDUs will be received
on the connected port). If a network (not a single device) is connected to the port, use of the Flush
Port option in order to prevent sending packets to disconnected links.
By default, the port is not an edge port. If the port is set as edge port, the Flush Port option is
disabled by default.
Command Syntax
device-name
(config-if
UU/SS/PP
)#
mstp edge-port
[
flush-port
]
device-name
(config-if
UU/SS/PP
)#
no mstp edge-port
[
flush-port
]
Argument Description
flush-port
(Optional). MSTP flushes the edge port on which is configured, when the link
on that port is down.
Setting the Link Type
The
mstp link-type
command, in Interface Configuration mode, sets the administrative status of
the MSTP port’s link state. The
no
form of the command resets the port’s administrative link type
to its default value (auto).
There are two statuses of link state: operational and administrative.
1. Admin Link-Type:
•
Auto
From the point of view of determining the value of the link-type, an MSTP port is
considered to be connected to a point-to-point LAN segment if any of the following
conditions are true: