In STP topology 3 (shown in the lower middle), if you have enabled the root guard feature on the STP port on Switch C that connects to
device D, and device D sends a superior BPDU that would trigger the election of device D as the new root bridge, the BPDU is ignored and
the port on Switch C transitions from a forwarding to a root-inconsistent state (shown by the green X icon). As a result, Switch A becomes
the root bridge.
Figure 127. STP Root Guard Prevents Bridging Loops
Configuring Root Guard
Enable STP root guard on a per-port or per-port-channel basis.
Dell Networking OS Behavior
: The following conditions apply to a port enabled with STP root guard:
•
Root guard is supported on any STP-enabled port or port-channel interface except when used as a stacking port.
•
Root guard is supported on a port in any Spanning Tree mode:
•
•
Rapid Spanning Tree Protocol (RSTP)
•
Multiple Spanning Tree Protocol (MSTP)
•
Per-VLAN Spanning Tree Plus (PVST+)
•
When enabled on a port, root guard applies to all VLANs configured on the port.
•
You cannot enable root guard and loop guard at the same time on an STP port. For example, if you configure root guard on a port on
which loop guard is already configured, the following error message displays:
• % Error: LoopGuard is configured.
Cannot configure RootGuard
.
•
When used in an MSTP network, if root guard blocks a boundary port in the CIST, the port is also blocked in all other MST instances.
To enable the root guard on an STP-enabled port or port-channel interface in instance 0, use the following command.
932
Spanning Tree Protocol (STP)
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 ...