D-Link xStack DES-3526DC User Manual page 68

xStack DES-3500 Series Layer 2 Stackable Fast Ethernet Managed Switch User Manual
NOTE: If you want to enable Forwarding BPDU on a per port basis, the following settings must first be
in effect: 1. STP must be globally disabled and 2. Forwarding BPDU must be globally enabled. These
are the default settings configurable in the STP Bridge Global Settings menu discussed previously.
The following STP Port Settings fields can be set:
Parameter
From/To
External Cost
Hello Time
Migration
Edge
P2P
Forward BPDU
LBD
State
Click Apply to implement changes made.
Description
A consecutive group of ports may be configured starting with the selected port.
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 0 (auto).
0 (auto) - Setting 0 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.
The time interval between transmissions of configuration messages by the designated port, to
other devices on the bridged LAN. The user may choose a time between 1 and 10 seconds.
The default is 2 seconds. This field is only operable when the Switch is enabled for MSTP.
Setting this parameter as "yes" will set the ports to send out BPDU 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.
Choosing the True parameter 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. Choosing the False parameter indicates that
the port does not have edge port status.
Choosing the True parameter 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 the port cannot
maintain this status, (for example if the port is forced to half-duplex operation) the p2p status
changes to operate as if the p2p value were false. The default setting for this parameter is
true.
Choosing True will allow the forwarding of BPDU packets in the specified ports from other
network devices. This will go into effect only if STP is globally disabled AND Forwarding BPDU
is globally enabled (See STP Bridge Global Settings above).
The default setting False, does not forward BPDU packets when STP is disabled.
Use the pull-down menu to enable or disable the loop-back detection function on the switch for
the ports configured above. For more information on this function, see the STP Loopback
Detection section.
This drop-down menu allows you to enable or disable STP for the selected group of ports. The
default is Enabled.
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