Cisco 7604-RSP720C-R Configuration Manual page 224

Information About vPCs
S e n d d o c u m e n t c o m m e n t s t o n e x u s 7 k - d o c f e e d b a c k @ c i s c o . c o m
STP is distributed; that is, the protocol continues running on both vPC peer devices. However, the
configuration on the vPC peer device elected as the primary device controls the STP process for the vPC
interfaces on the secondary vPC peer device.
The primary vPC device synchronizes the STP state on the vPC secondary peer device using Cisco
Fabric Services over Ethernet (CFSoE). See the
CFSoE.
The STP process for vPC also relies on the periodic keepalive messages to determine when one of the
connected devices on the peer link fails. See the
page 7-11
The vPC manager performs a proposal/handshake agreement between the vPC peer devices that set the
primary and secondary devices and coordinates the two devices for STP. The primary vPC peer device
then controls the STP protocol on both the primary and secondary devices. We recommend that you
configure the primary vPC peer device as the STP primary root device and configure the secondary VPC
device to be the STP secondary root device.
If the primary vPC peer device fails over to the secondary vPC peer device, there is no change in the STP
topology.
The BPDUs uses the MAC address set for the vPC for the STP bridge ID in the designated bridge ID
field. The vPC primary device sends these BPDUs on the vPC interfaces.
You must configure both ends of vPC peer link with the identical STP configuration for the following
parameters:
STP global settings:
•
–
–
–
–
–
–
STP interface settings:
•
–
–
–
If any of these parameters are misconfigured, the Cisco NX-OS software suspends all interfaces in the
Note
vPC. Check the syslog and enter the show vpc brief command to see if the vPC interfaces are suspended.
Ensure that the following STP interface configurations are identical on both sides of the vPC peer links
or you may see unpredictable behavior in the traffic flow:
BPDU Filter
•
• BPDU Guard
• Cost
• Link type
Priority
•
Cisco Nexus 7000 Series NX-OS Interfaces Configuration Guide, Release 5.x
7-22
for information on these messages.
STP mode
STP region configuration for MST
Enable/disable state per VLAN
Bridge Assurance setting
Port type setting
Loop Guard settings
Port type setting
Loop Guard
Root Guard
"CFSoE" section on page 7-26
"Peer-Keepalive Link and Messages" section on
Chapter 7 Configuring vPCs
for information on
OL-23435-03