D-Link DGS-3600 Series User Manual page 145

It is advisable to define an STP Group to correspond to a VLAN group of ports.
The following STP Port Settings fields can be set:
Parameter Description
From/To A consecutive group of ports may be configured starting with the selected port.
External Cost
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.
Hello Time 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.
Migration When operating in RSTP mode, selecting yes forces the port that has been selected to
transmit RSTP BPDUs.
Choosing the True parameter designates the port as an edge port. Edge ports cannot create
Edge
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.
P2P 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
xStack DGS-3600 Series Layer 3 Gigabit Ethernet Managed Switch
Figure 7- 47. STP Port Settings window
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