D-Link DSL-G604T Parameter Description From/To, External Cost 0 =, Auto, Hello Time, Migration

DGS-3024 Gigabit Ethernet Switch 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 based on 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:

Parameter	Description
From/To	A consecutive group of ports may be configured starting with the selected port.
External Cost (0 =	This defines a metric that indicates the relative cost of forwarding packets to the
Auto)	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 the transmission of configuration messages by the des-
	ignated port, to other devices on the bridged LAN, thus stating that the Switch is still
	functioning. 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	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.
Edge	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.
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

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