C
HAPTER
37
| Spanning Tree Commands
– 880 –
C
OMMAND
U
SAGE
◆
This command defines the priority for the use of a port in the Spanning
Tree Algorithm. If the path cost for all ports on a switch are the same,
the port with the highest priority (that is, lowest value) will be
configured as an active link in the spanning tree.
◆
Where more than one port is assigned the highest priority, the port with
lowest numeric identifier will be enabled.
E
XAMPLE
Console(config)#interface ethernet 1/5
Console(config-if)#spanning-tree port-priority 0
R
ELATED
C
OMMANDS
spanning-tree cost (873)
spanning-tree root-
guard
This command prevents a designated port
17
from taking superior BPDUs
into account and allowing a new STP root port to be elected. Use the
no
form to disable this feature.
S
YNTAX
[
no
]
spanning-tree root-guard
D
EFAULT
S
ETTING
Disabled
C
OMMAND
M
ODE
Interface Configuration (Ethernet, Port Channel)
C
OMMAND
U
SAGE
◆
A bridge with a lower bridge identifier (or same identifier and lower
MAC address) can take over as the root bridge at any time.
◆
When Root Guard is enabled, and the switch receives a superior BPDU
on this port, it is set to the Discarding state until it stops receiving
superior BPDUs for a fixed recovery period. While in the discarding
state, no traffic is forwarded across the port.
◆
Root Guard can be used to ensure that the root bridge is not formed at
a suboptimal location. Root Guard should be enabled on any designated
port connected to low-speed bridges which could potentially overload a
slower link by taking over as the root port and forming a new spanning
tree topology. It could also be used to form a border around part of the
network where the root bridge is allowed.
◆
When spanning tree is initialized globally on the switch or on an
interface, the switch will wait for 20 seconds to ensure that the
spanning tree has converged before enabling Root Guard.
17. See Port Role under
"Displaying Interface Settings for STA" on page 217
.
Содержание LGB6026A
Страница 6: ...ABOUT THIS GUIDE 4...
Страница 40: ...38 CONTENTS...
Страница 60: ...58 SECTION I Getting Started...
Страница 86: ...84 SECTION II Web Configuration Unicast Routing on page 517 Multicast Routing on page 575...
Страница 162: ...160 CHAPTER 5 Interface Configuration VLAN Trunking...
Страница 196: ...194 CHAPTER 6 VLAN Configuration Configuring MAC based VLANs...
Страница 204: ...CHAPTER 7 Address Table Settings Clearing the Dynamic Address Table 202...
Страница 238: ...CHAPTER 11 Class of Service Layer 2 Queue Settings 236...
Страница 254: ...252 CHAPTER 12 Quality of Service Attaching a Policy Map to a Port...
Страница 448: ...446 CHAPTER 16 Multicast Filtering Multicast VLAN Registration...
Страница 470: ...468 CHAPTER 17 IP Configuration Setting the Switch s IP Address IP Version 6...
Страница 576: ...574 CHAPTER 21 Unicast Routing Configuring the Open Shortest Path First Protocol Version 2...
Страница 606: ...604 CHAPTER 22 Multicast Routing Configuring PIMv6 for IPv6...
Страница 620: ...618 CHAPTER 23 Using the Command Line Interface CLI Command Groups...
Страница 672: ...670 CHAPTER 25 System Management Commands Time Range...
Страница 692: ...690 CHAPTER 26 SNMP Commands...
Страница 700: ...698 CHAPTER 27 Remote Monitoring Commands...
Страница 854: ...CHAPTER 34 Port Mirroring Commands Local Port Mirroring Commands 852...
Страница 862: ...860 CHAPTER 36 Address Table Commands...
Страница 958: ...956 CHAPTER 40 Quality of Service Commands...
Страница 1034: ...1032 CHAPTER 42 LLDP Commands...
Страница 1044: ...1042 CHAPTER 43 Domain Name Service Commands...
Страница 1062: ...1060 CHAPTER 44 DHCP Commands DHCP Server...
Страница 1206: ...CHAPTER 47 IP Routing Commands Open Shortest Path First OSPFv3 1204...
Страница 1250: ...1248 SECTION IV Appendices...
Страница 1256: ...1254 APPENDIX A Software Specifications Management Information Bases...
Страница 1278: ...1276 COMMAND LIST...