D-Link DWS-1008 Product Manual - Page 227

Port Fast Convergence, Backbone Fast Convergence, Uplink Fast Convergence, Configuring Port Fast

Page 227 highlights

Port Fast Convergence Port fast convergence bypasses both the listening and learning stages and immediately places a port in the forwarding state. You can use port fast convergence on ports that are directly connected to servers, hosts, or other MAC stations. Note: Do not use port fast convergence on ports connected to other bridges. Backbone Fast Convergence Backbone fast convergence accelerates a port's recovery following the failure of an indirect link. Normally, when a forwarding link fails, a bridge that is not directly connected to the link does not detect the link change until the maximum age timer expires. Backbone fast convergence enables the switch to listen for bridge protocol data units (BPDUs) sent by a designated bridge when the designated bridge's link to the root bridge fails. The switch immediately verifies whether BPDU information stored on a port is still valid. If not, the bridge immediately starts the listening stage on the port. Note: If you plan to use the backbone fast convergence feature, you must enable it on all the bridges in the spanning tree. Uplink Fast Convergence Uplink fast convergence enables a switch that has redundant links to the network core to immediately change the state of a backup link to forwarding if the primary link to the root fails. Uplink fast convergence bypasses the listening and learning states to immediately enter the forwarding state. Note: The uplink fast convergence feature is applicable to bridges that are acting as access switches to the network core (distribution layer) but are not in the core themselves. Do not enable the feature on DWS-1008 switches that are in the network core. Configuring Port Fast Convergence To enable or disable port fast convergence, use the following command: set spantree portfast port port-list {enable | disable} To enable port fast convergence on ports 1, 3, and 5, type the following command: DWS-1008# set spantree portfast port 1,3,5 enable success: change accepted. D-Link DWS-1008 User Manual 208

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D-Link DWS-1008 User Manual
±08
Port Fast Convergence
Port fast convergence bypasses both the listening and learning stages and immediately places a port in
the forwarding state. You can use port fast convergence on ports that are directly connected to servers,
hosts, or other MAC stations.
Note:
Do not use port fast convergence on ports connected to other bridges.
Backbone Fast Convergence
Backbone fast convergence accelerates a port’s recovery following the failure of an indirect link. Normally,
when a forwarding link fails, a bridge that is not directly connected to the link does not detect the link
change until the maximum age timer expires. Backbone fast convergence enables the switch to listen
for bridge protocol data units (BPDUs) sent by a designated bridge when the designated bridge’s link to
the root bridge fails. The switch immediately verifies whether BPDU information stored on a port is still
valid. If not, the bridge immediately starts the listening stage on the port.
Note:
If you plan to use the backbone fast convergence feature, you must enable it on all the bridges
in the spanning tree.
Uplink Fast Convergence
Uplink fast convergence enables a switch that has redundant links to the network core to immediately
change the state of a backup link to forwarding if the primary link to the root fails. Uplink fast convergence
bypasses the listening and learning states to immediately enter the forwarding state.
Note:
The uplink fast convergence feature is applicable to bridges that are acting as access switches
to the network core (distribution layer) but are not in the core themselves. Do not enable the feature on
DWS-1008 switches that are in the network core.
Configuring Port Fast Convergence
To enable or disable port fast convergence, use the following command:
set spantree portfast port
port-list
{enable | disable}
To enable port fast convergence on ports 1, 3, and 5, type the following command:
DWS-1008#
set spantree portfast port 1,3,5 enable
success: change accepted.