CAUTION:
Enable PortFast only on links connecting to an end station. PortFast can cause loops if it is enabled on an interface
connected to a network.
To enable PortFast on an interface, use the following command.
•
Enable PortFast on an interface.
INTERFACE mode
spanning-tree
stp-id
portfast [bpduguard | [shutdown-on-violation]]
Example of Verifying PortFast is Enabled on an Interface
To verify that PortFast is enabled on a port, use the
show spanning-tree
command from EXEC Privilege mode or the
show config
command from INTERFACE mode. Dell Networking recommends using the
show config
command.
Dell#(conf-if-te-1/1)#show conf
!
interface TenGigabitEthernet 1/1
no ip address
switchport
spanning-tree 0 portfast
no shutdown
Dell#(conf-if-te-1/1)#
Prevent Network Disruptions with BPDU Guard
Configure the Portfast (and Edgeport, in the case of RSTP, PVST+, and MSTP) feature on ports that connect to end stations. End stations
do not generate BPDUs, so ports configured with Portfast/ Edgport (edgeports) do not expect to receive BDPUs.
If an edgeport does receive a BPDU, it likely means that it is connected to another part of the network, which can negatively affect the
STP topology. The BPDU Guard feature blocks an edgeport after receiving a BPDU to prevent network disruptions, and Dell Networking
OS displays the following message.
3w3d0h: %RPM0-P:RP2 %SPANMGR-5-BPDU_GUARD_RX_ERROR: Received Spanning Tree BPDU on
BPDU guard port. Disable TenGigabitEthernet 3/4.
Enable BPDU Guard using the
bpduguard
option when enabling PortFast or EdgePort. The
bpduguard shutdown-on-violation
option causes the interface hardware to be shut down when it receives a BPDU. Otherwise, although the interface is placed in an Error
Disabled state when receiving the BPDU, the physical interface remains up and spanning-tree will only drop packets after a BPDU violation.
The following example shows a scenario in which an edgeport might unintentionally receive a BPDU. The port on the Dell Networking
system is configured with Portfast. If the switch is connected to the hub, the BPDUs that the switch generates might trigger an
undesirable topology change. If you enable BPDU Guard, when the edge port receives the BPDU, the BPDU is dropped, the port is blocked,
and a console message is generated.
NOTE:
Unless you enable the
shutdown-on-violation
option, spanning-tree only drops packets after a BPDU violation; the
physical interface remains up.
Dell Networking OS Behavior
: Regarding
bpduguard shutdown-on-violation
behavior:
•
If the interface to be shut down is a port channel, all the member ports are disabled in the hardware.
•
When you add a physical port to a port channel already in the Error Disable state, the new member port is also disabled in the hardware.
•
When you remove a physical port from a port channel in the Error Disable state, the Error Disabled state is cleared on this physical port
(the physical port is enabled in the hardware).
•
You can clear the Error Disabled state with any of the following methods:
•
Perform a
shutdown
command on the interface.
•
Disable the
shutdown-on-violation
command on the interface (the
no spanning-tree
stp-id
portfast
[bpduguard | [shutdown-on-violation]]
command).
Spanning Tree Protocol (STP)
929
Содержание S4048T-ON
Страница 1: ...Dell Configuration Guide for the S4048 ON System 9 11 2 1 ...
Страница 148: ...Figure 10 BFD Three Way Handshake State Changes 148 Bidirectional Forwarding Detection BFD ...
Страница 251: ...Dell Control Plane Policing CoPP 251 ...
Страница 363: ... RPM Synchronization GARP VLAN Registration Protocol GVRP 363 ...
Страница 511: ...Figure 64 Inspecting the LAG Configuration Link Aggregation Control Protocol LACP 511 ...
Страница 512: ...Figure 65 Inspecting Configuration of LAG 10 on ALPHA 512 Link Aggregation Control Protocol LACP ...
Страница 515: ...Figure 67 Inspecting a LAG Port on BRAVO Using the show interface Command Link Aggregation Control Protocol LACP 515 ...
Страница 516: ...Figure 68 Inspecting LAG 10 Using the show interfaces port channel Command 516 Link Aggregation Control Protocol LACP ...
Страница 558: ...Figure 84 Configuring Interfaces for MSDP 558 Multicast Source Discovery Protocol MSDP ...
Страница 559: ...Figure 85 Configuring OSPF and BGP for MSDP Multicast Source Discovery Protocol MSDP 559 ...
Страница 560: ...Figure 86 Configuring PIM in Multiple Routing Domains 560 Multicast Source Discovery Protocol MSDP ...
Страница 564: ...Figure 88 MSDP Default Peer Scenario 2 564 Multicast Source Discovery Protocol MSDP ...
Страница 565: ...Figure 89 MSDP Default Peer Scenario 3 Multicast Source Discovery Protocol MSDP 565 ...
Страница 729: ...protocol spanning tree pvst no disable vlan 300 bridge priority 4096 Per VLAN Spanning Tree Plus PVST 729 ...
Страница 841: ...Figure 115 Single and Double Tag TPID Match Service Provider Bridging 841 ...
Страница 842: ...Figure 116 Single and Double Tag First byte TPID Match 842 Service Provider Bridging ...