User manual

4 Configuration DES-1210 Metro Ethernet Managed Switch User Manual
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State: Use the drop-down menu to enable or disable STP by per-port based. It will be selectable after the
global STP is enabled.
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. Thedefault 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.
Migrate: 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. Migration should be set as yes on ports connected to network
stations or segments that are capable of being upgraded to 802.1w RSTP on all or some portion of the
segment.
Edge: Selecting 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. Selecting the False parameter indicates that the port does not have edge port status. Selecting
the Auto parameter indicates that the port have edge port status or not have edge port status automatically.
Priority: Specify the priority of each port. Selectable range is from 0 to 240, and the default setting is 128.
The lower the number, the greater the probability the port will be chosen as a root port.
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 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 Auto.
Restricted Role: Toggle between True and False to set the restricted role state of the packet. If set to True,
the port will never be selected to be the Root port. The default value is False.
Restricted TCN: Toggle between True and False to set the restricted TCN of the packet. Topology Change
Notification (TCN) is a BPDU that a bridge sends out to its root port to signal a topology change. If set to
True, it stops the port from propagating received TCN and to other ports. The default value is False.
Forwarding BPDU: Bridges use Bridge Protocol Data Units (BPDU) to provide spanning tree information.
STP BPDUs filtering is useful when a bridge interconnects two regions; each region needing a separate
spanning tree. BPDU filtering functions only when STP is disabled either globally or on a single interface.
The possible field values are:
Disabled – BPDU filtering is enabled on the port.
Enabled – BPDU forwarding is enabled on the port (if STP is disabled).
Hello Time: The interval between two transmissions of BPDU packets sent by the Root Bridge to indicate to
all other switches that it is indeed the Root Bridge. The default value is 2.
Click Apply for the settings to take effect. Click Refresh to renew the page.
Configuration > Spanning Tree > MST Configuration Identification
The MST Configuration Identification page allows user to configure a MSTI instance on the switch. These
settings will uniquely identify a multiple spanning tree instance set on the switch. The Switch initially
possesses one CIST or Common Internal Spanning Tree of which the user may modify the parameters for
but cannot change the MSTI ID for, and cannot be deleted.