10-31-2011 08:45 AM - edited 03-07-2019 03:08 AM
Hello,
Is Uplinkfast enabled in RSTP ?
S1#show spanning-tree
VLAN0001
Spanning tree enabled protocol rstp
S1#show spanning-tree uplinkfast
UplinkFast is enabled but inactive in rapid-pvst mode
I see it says is enabled, but inactive, but yet there are some ports in ALT state. However, if it should be enabled by default, it shouldn't modify the ports costs to high values, and also the bridge priority ?
Solved! Go to Solution.
10-31-2011 09:00 AM
Hi Alex,
RSTP natively contains improvements similar to UplinkFast and BackboneFast that can not be disabled. You do not need to enable anything special to already have the necessary functionality. The UplinkFast and BackboneFast will be reported as disabled in your output because RSTP uses its own implementations of the same improvements. In fact, it is not appropriate to try to enable UplinkFast and BackboneFast when running RSTP.
Best regards,
Peter
10-31-2011 09:00 AM
Hi Alex,
RSTP natively contains improvements similar to UplinkFast and BackboneFast that can not be disabled. You do not need to enable anything special to already have the necessary functionality. The UplinkFast and BackboneFast will be reported as disabled in your output because RSTP uses its own implementations of the same improvements. In fact, it is not appropriate to try to enable UplinkFast and BackboneFast when running RSTP.
Best regards,
Peter
10-31-2011 09:05 AM
Hi,
In addition to what Peter noted, when uplink fast is enable the switch priority is changed.
See example
Before uplink fast is enabled
Switch(config)#do sh spann
VLAN0001
Spanning tree enabled protocol ieee
Root ID Priority 32769
Address 001b.5400.3380
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
Address 001b.5400.3380
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec
Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/0/1 Desg FWD 19 128.1 P2p
after uplink fast is enabled
Switch(config)#spann
Switch(config)#spanning-tree up
Switch(config)#spanning-tree uplinkfast
Switch(config)#do sh spann
VLAN0001
Spanning tree enabled protocol ieee
Root ID Priority 49153
Address 001b.5400.3380
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 49153 (priority 49152 sys-id-ext 1)
Address 001b.5400.3380
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec
Uplinkfast enabled
Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/0/1 Desg FWD 3019 128.1 P2p
Switch(config)#
HTH
10-31-2011 09:40 AM
Yes, I know, that happens in traditional mode stp, I was reffering to RSTP.
However, things are clear now, UPlinkfast does not exist in RSTP, but simmilar implementations are available by default.
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