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state when receiving the BPDU, the physical interface remains up and spanning-tree drops packets in the hardware after a BPDU
violation. BPDUs are dropped in the software after receiving the BPDU violation.
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).
•
The
reset linecard
command does not clear the Error Disabled state of the port or the Hardware Disabled state. The
interface continues to be disables in the hardware.
•
You can clear the Error Disabled state with any of the following methods:
850
Spanning Tree Protocol (STP)
Содержание S4048-ON
Страница 1: ...Dell Configuration Guide for the S4048 ON System 9 9 0 0 ...
Страница 146: ...Figure 14 BFD Three Way Handshake State Changes 146 Bidirectional Forwarding Detection BFD ...
Страница 477: ...Figure 68 Inspecting Configuration of LAG 10 on ALPHA Link Aggregation Control Protocol LACP 477 ...
Страница 480: ...Figure 70 Inspecting a LAG Port on BRAVO Using the show interface Command 480 Link Aggregation Control Protocol LACP ...
Страница 481: ...Figure 71 Inspecting LAG 10 Using the show interfaces port channel Command Link Aggregation Control Protocol LACP 481 ...
Страница 522: ...Figure 87 Configuring Interfaces for MSDP 522 Multicast Source Discovery Protocol MSDP ...
Страница 523: ...Figure 88 Configuring OSPF and BGP for MSDP Multicast Source Discovery Protocol MSDP 523 ...
Страница 524: ...Figure 89 Configuring PIM in Multiple Routing Domains 524 Multicast Source Discovery Protocol MSDP ...
Страница 528: ...Figure 91 MSDP Default Peer Scenario 1 528 Multicast Source Discovery Protocol MSDP ...
Страница 529: ...Figure 92 MSDP Default Peer Scenario 2 Multicast Source Discovery Protocol MSDP 529 ...
Страница 530: ...Figure 93 MSDP Default Peer Scenario 3 530 Multicast Source Discovery Protocol MSDP ...
Страница 633: ...Policy based Routing PBR 633 ...
Страница 777: ...Figure 119 Single and Double Tag TPID Match Service Provider Bridging 777 ...
Страница 778: ...Figure 120 Single and Double Tag First byte TPID Match 778 Service Provider Bridging ...