Forwarding & Filtering - D-Link DGS-3312SR Product Manual

In addition to setting Spanning Tree parameters for use on the Switch level, the Switch allows for the configuration of
groups of ports, each port-group of which will have its own spanning tree, and will require some of its own configuration
settings. An STP Group will use the Switch-level parameters entered above, with the addition of Port Priority and Port
Cost.
An STP Group spanning tree works in the same way as the Switch-level spanning tree, but the root bridge concept is
replaced with a root port concept. A root port is a port of the group that is elected on the basis of port priority and port cost,
to be the connection to the network for the group. Redundant links will be blocked, just as redundant links are blocked on
the Switch level.
The STP on the Switch level blocks redundant links between Switches (and similar network devices). The port level STP
will block redundant links within an STP Group.
It is advisable to define an STP Group to correspond to a VLAN group of ports.
The following fields can be set for STP port configuration:
Parameter
Unit
From/To
State
Cost
Priority
Migration
Edge
P2P
Forwarding & Filtering
The Switch allows permanent or static entries into the forwarding database (FDB). These FDB entries are MAC addresses
that will not age out. In addition, multicast forwarding may be customized to conform to rules for the different ports by
setting up multicast filter modes for each port.
DGS-3312SR Gigabit Layer 3 Switch
Description
This is the Unit ID of a Switch in a Switch stack. The number 15 indicates a DGS-
3312SR Switch in standalone mode.
A consecutive group of ports may be configured starting with the selected port.
This drop-down menu allows you to enable or disable STP for the selected group of
ports.
A Port Cost can be set from 1 to 200000000. The lower the number, the greater the
probability the port will be chosen to forward packets.
Default port cost:
100Mbps port = 200000
Gigabit ports = 20000
A Port Priority can be from 0 to 240. The lower the number, the greater the probability
the port will be chosen as the Root Port.
Select Yes or No. Choosing Yes will enable the port to migrate from 802.1d STP
status to 802.1w RSTP status. RSTP can coexist with standard STP, however the
benefits of RSTP are not realized on a port where an 802.1d network connects to an
802.1w enabled network. Migration should be enabled (Yes) on ports connected to
network stations or segments that will be upgraded to 802.1w RSTP on all or some
portion of the segment.
Select Yes or No. Choosing Yes 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.
No indicates the port does not have edge port status.
Select Yes or No. Choosing Yes indicates a point-to-point (p2p) shared link. These
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.
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