D-Link DES-3526 Manual page 68

settings configurable in the STP Bridge Global Settings menu discussed
previously.
The following STP Port Settings fields can be set:
Parameter Description
From/To <Port 1>
External Cost < 0 = Auto>
Hello Time <1>
Migration <Yes>
Edge <False>
P2P <True>
Forward BPDU <False>
DES-3526 / DES-3526DC Fast Ethernet Layer 2 Switch
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 des-
ignated 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 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.
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).
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