Configuring Loop Guard
Enable STP loop guard on a per-port or per-port channel basis.
The following conditions apply to a port enabled with loop guard:
•
Loop guard is supported on any STP-enabled port or port-channel interface.
•
Loop guard is supported on a port or port-channel in any spanning tree mode:
•
•
Rapid Spanning Tree Protocol (RSTP)
•
Multiple Spanning Tree Protocol (MSTP)
•
Per-VLAN Spanning Tree Plus (PVST+)
•
You cannot enable root guard and loop guard at the same time on an STP port. For example, if you configure loop guard on a port on
which root guard is already configured, the following error message is displayed:
% Error: RootGuard is configured.
Cannot configure LoopGuard
.
•
Enabling Portfast BPDU guard and loop guard at the same time on a port results in a port that remains in a blocking state and prevents
traffic from flowing through it. For example, when Portfast BPDU guard and loop guard are both configured:
•
If a BPDU is received from a remote device, BPDU guard places the port in an Err-Disabled Blocking state and no traffic is
forwarded on the port.
•
If no BPDU is received from a remote device, loop guard places the port in a Loop-Inconsistent Blocking state and no traffic is
forwarded on the port.
•
When used in a PVST+ network, STP loop guard is performed per-port or per-port channel at a VLAN level. If no BPDUs are received
on a VLAN interface, the port or port-channel transitions to a Loop-Inconsistent (Blocking) state only for this VLAN.
To enable a loop guard on an STP-enabled port or port-channel interface, use the following command.
•
Enable loop guard on a port or port-channel interface.
INTERFACE mode or INTERFACE PORT-CHANNEL mode
spanning-tree {0 | mstp | rstp | pvst} loopguard
•
0
: enables loop guard on an STP-enabled port assigned to instance 0.
•
mstp
: enables loop guard on an MSTP-enabled port.
•
rstp
: enables loop guard on an RSTP-enabled port.
•
pvst
: enables loop guard on a PVST-enabled port.
To disable STP loop guard on a port or port-channel interface, use the
no spanning-tree 0 loopguard
command in an INTERFACE
configuration mode.
To verify the STP loop guard configuration on a port or port-channel interface, use the
show spanning-tree 0 guard
[interface
interface
]
command in a global configuration mode.
Displaying STP Guard Configuration
To display the STP guard configuration, use the following command.
The following example shows an STP network (instance 0) in which:
•
Root guard is enabled on a port that is in a root-inconsistent state.
•
Loop guard is enabled on a port that is in a listening state.
•
BPDU guard is enabled on a port that is shut down (Error Disabled state) after receiving a BPDU.
•
Verify the STP guard configured on port or port-channel interfaces.
show spanning-tree 0 guard [interface
interface
]
Spanning Tree Protocol (STP)
837
Содержание S3048-ON
Страница 1: ...Dell Configuration Guide for the S3048 ON System 9 11 2 5 ...
Страница 137: ...0 Gi 1 1 Gi 1 2 rx Flow N A N A 0 0 No N A N A yes Access Control Lists ACLs 137 ...
Страница 142: ...Figure 10 BFD Three Way Handshake State Changes 142 Bidirectional Forwarding Detection BFD ...
Страница 241: ...Dell Control Plane Policing CoPP 241 ...
Страница 287: ... RPM Synchronization GARP VLAN Registration Protocol GVRP 287 ...
Страница 428: ...Figure 53 Inspecting the LAG Configuration 428 Link Aggregation Control Protocol LACP ...
Страница 429: ...Figure 54 Inspecting Configuration of LAG 10 on ALPHA Link Aggregation Control Protocol LACP 429 ...
Страница 432: ...Figure 56 Inspecting a LAG Port on BRAVO Using the show interface Command 432 Link Aggregation Control Protocol LACP ...
Страница 433: ...Figure 57 Inspecting LAG 10 Using the show interfaces port channel Command Link Aggregation Control Protocol LACP 433 ...
Страница 477: ...Figure 73 Configuring Interfaces for MSDP Multicast Source Discovery Protocol MSDP 477 ...
Страница 478: ...Figure 74 Configuring OSPF and BGP for MSDP 478 Multicast Source Discovery Protocol MSDP ...
Страница 479: ...Figure 75 Configuring PIM in Multiple Routing Domains Multicast Source Discovery Protocol MSDP 479 ...
Страница 483: ...Figure 77 MSDP Default Peer Scenario 2 Multicast Source Discovery Protocol MSDP 483 ...
Страница 484: ...Figure 78 MSDP Default Peer Scenario 3 484 Multicast Source Discovery Protocol MSDP ...
Страница 634: ...protocol spanning tree pvst no disable vlan 300 bridge priority 4096 634 Per VLAN Spanning Tree Plus PVST ...
Страница 745: ...Figure 104 Single and Double Tag TPID Match Service Provider Bridging 745 ...
Страница 746: ...Figure 105 Single and Double Tag First byte TPID Match 746 Service Provider Bridging ...