
spanning-tree {0 | mstp | rstp | pvst} rootguard
–
0
: enables root guard on an STP-enabled port assigned to instance 0.
–
mstp
: enables root guard on an MSTP-enabled port.
–
rstp
: enables root guard on an RSTP-enabled port.
–
pvst
: enables root guard on a PVST-enabled port.
To disable STP root guard on a port or port-channel interface, use the
no spanning-tree 0 rootguard
command in an
interface configuration mode.
To verify the STP root guard configuration on a port or port-channel interface, use the
show spanning-tree 0 guard
[interface
interface
]
command in a global configuration mode.
Enabling SNMP Traps for Root Elections and Topology Changes
To enable SNMP traps individually or collectively, use the following commands.
•
Enable SNMP traps for spanning tree state changes.
snmp-server enable traps stp
•
Enable SNMP traps for RSTP, MSTP, and PVST+ collectively.
snmp-server enable traps xstp
Configuring Spanning Trees as Hitless
You can configure STP, RSTP, MSTP, and PVST+ to be hitless (configure all or none as hitless). When configured as hitless, critical
protocol state information is synchronized between the RPMs so that RPM failover is seamless and no topology change is triggered.
To be hitless per spanning tree type or for all spanning tree types, use the following commands.
•
Configure LACP to be hitless.
CONFIGURATION mode
redundancy protocol lacp
•
Configure all spanning tree types to be hitless.
CONFIGURATION mode
redundancy protocol xstp
Example of Configuring all Spanning Tree Types to be Hitless
Dell(conf)#redundancy protocol xstp
Dell#show running-config redundancy
!
redundancy protocol xstp
Dell#
STP Loop Guard
The STP loop guard feature provides protection against Layer 2 forwarding loops (STP loops) caused by a hardware failure, such as a
cable failure or an interface fault. When a cable or interface fails, a participating STP link may become unidirectional (STP requires
links to be bidirectional) and an STP port does not receive BPDUs. When an STP blocking port does not receive BPDUs, it transitions
to a Forwarding state. This condition can create a loop in the network.
For example, in the following example (STP topology 1, upper left), Switch A is the root switch and Switch B normally transmits
BPDUs to Switch C. The link between Switch C and Switch B is in a Blocking state. However, if there is a unidirectional link failure
(STP topology 1, lower left), Switch C does not receive BPDUs from Switch B. When the
max-age
timer expires, the STP port on
Switch C becomes unblocked and transitions to Forwarding state. A loop is created as both Switch A and Switch C transmit traffic
to Switch B.
854
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 ...