xStack® DES-3528/DES-3552 Series Layer 2 Managed Stackable Fast Ethernet Switch CLI Reference Guide
90
config stp ports
Purpose
Used to setup STP on the port level.
Syntax
config stp ports <portlist> { externalCost [ auto | <value 1-200000000> ] | hellotime
<value 1-2> | migrate [yes | no ] | edge [ true | false | auto ] | p2p [ true | false | auto ] |
state [enable | disable ] | restricted_role [true | false] | restricted_tcn [true | false ] |
fbpdu [enable | disable ] }(1)
Description
This command is used to create and configure STP for a group of ports.
Parameters
<portlist>
−
Specifies a range of ports to be configured.
externalCost
−
This defines a metric that indicates the relative cost of forwarding packets to
the specified port list. Port cost can be set automatically or as a metric value. The default
value is
auto
.
auto
– Setting this parameter for the external cost will automatically set the speed for
forwarding packets to the specified port(s) in the list for optimal efficiency. Default port
cost: 100Mbps port = 200000. Gigabit port = 20000.
<value 1-200000000>
−
Define a value between 1 and 200000000 to determine the
external cost. The lower the number, the greater the probability the port will be chosen
to forward packets.
hellotime <value 1-2>
−
The time interval between transmission of configuration messages
by the designated port, to other devices on the bridged LAN, thus stating that the Switch is
still functioning. The user may choose a time between 1 and
2
seconds. The default is 2
seconds.
migrate [yes | no]
– Setting this parameter as “
yes
” will set the ports to send out BDPU
packets to other bridges, requesting information on their STP setting If the Switch is
configured for RSTP, the port will be capable to migrate from 802.1D STP to 802.1w RSTP.
If the Switch is configured for MSTP, the port is capable of migrating from 802.1D STP to
802.1s MSTP. RSTP and MSTP can coexist with standard STP, however the benefits of
RSTP and MSTP are not realized on a port where an 802.1D network connects to an 802.1w
or 802.1s enabled network. Migration should be set as
yes
on ports connected to network
stations or segments that are capable of being upgraded to 802.1w RSTP or 802.1s MSTP
on all or some portion of the segment.
edge [true | false | auto]
–
true
designates the port as an edge port. Edge ports cannot create
loops, however an edge port can lose edge port status if a topology change creates a
potential for a loop. An edge port normally should not receive BPDU packets. If a BPDU
packet is received it automatically loses edge port status.
false
indicates that the port does
not have edge port status.
auto
– Indicates that the port will be able to automatically enable the edge port status if this
port links to an end station or a device that does not support the STP function. The default
setting for this parameter is false.
restricted_role
[true | false]
– If
true
causes the Port not to be selected as Root Port for the
CIST or any MSTI, even it has the best spanning tree priority vector. Such a Port will be
selected as an Alternate Port after the Root Port has been selected. This parameter should
be
false
by default. If set, it can cause lack of spanning tree connectivity. It is 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. The default setting for this parameter is false.
restricted_tcn
[true | false]
– If
true
causes the Port not to propagate received topology
change notifications and topology changes to other Ports. This parameter should be
false
by
default. If set it can cause temporary loss of connectivity after changes in a spanning trees
active topology as a result of persistent incorrectly learned station location information. It is
set by a network administrator to prevent bridges external to a core region of the network,
causing address flushing in that region, possibly because those bridges are not under the full
control of the administrator or MAC_Operational for the attached LANs transitions frequently.
The default setting for this parameter is false.
p2p [true | false | auto]
–
true
indicates a point-to-point (P2P) shared link. P2P ports are
similar to edge ports however they are restricted in that a P2P port must operate in full-
duplex. Like edge ports, P2P ports transition to a forwarding state rapidly thus benefiting
from RSTP. A p2p value of false indicates that the port cannot have p2p status.
Auto
allows
the port to have p2p status whenever possible and operate as if the p2p status were
true
. If
