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New Member

UPLINKFAST

Hi to all switching experts,

since someweeks we receive some logging messages we can´t explain. The network setup is:

2 Cat 4006 in the core connected through 1 etherchannel (4 GOG Links)

around 30 Cat 3500xl in the Access-Layer connected to the cores by redundant links. some cat3500xls are cascaded. All Links are configured as trunks. Using multiple Vlans the SPT Roots are distributed to the 2 CAT 4006 Switches.

We activate the uplinkfast feature. This works all fine.

Now we receive some messages wich indicate that the uplinkfast feature was triggered. According to cisco docu the feature is triggered by a linkfailuure of the switch itself. But we couldn´t find any message that shows a link down of any trunk...

Is it possible, that the uplinkfast ist triggered by an other event? Any ideas?

140182: Apr 30 07:20:16: %SPANTREE_FAST-6-PORT_FWD_UPLINK: Port GigabitEthernet0/1 in vlan 37 moved to Forwarding (UplinkFast).
140183: Apr 30 07:20:16: %SPANTREE_FAST-6-PORT_FWD_UPLINK: Port GigabitEthernet0/1 in vlan 50 moved to Forwarding (UplinkFast).
140184: Apr 30 07:20:16: %SPANTREE_FAST-6-PORT_FWD_UPLINK: Port GigabitEthernet0/1 in vlan 99 moved to Forwarding (UplinkFast).
140185: Apr 30 07:20:17: %SPANTREE_FAST-6-PORT_FWD_UPLINK: Port GigabitEthernet0/1 in vlan 1 moved to Forwarding (UplinkFast).
140186: Apr 30 07:20:17: %SPANTREE_FAST-6-PORT_FWD_UPLINK: Port GigabitEthernet0/1 in vlan 33 moved to Forwarding (UplinkFast).
140187: Apr 30 07:20:17: %SPANTREE_FAST-6-PORT_FWD_UPLINK: Port GigabitEthernet0/1 in vlan 49 moved to Forwarding (UplinkFast).
140188: Apr 30 07:20:23: %SPANTREE_FAST-6-PORT_FWD_UPLINK: Port GigabitEthernet0/2 in vlan 99 moved to Forwarding (UplinkFast).
140189: Apr 30 07:20:23: %SPANTREE_FAST-6-PORT_FWD_UPLINK: Port GigabitEthernet0/2 in vlan 50 moved to Forwarding (UplinkFast).
140190: Apr 30 07:20:23: %SPANTREE_FAST-6-PORT_FWD_UPLINK: Port GigabitEthernet0/2 in vlan 37 moved to Forwarding (UplinkFast).
140191: Apr 30 07:20:23: %SPANTREE_FAST-6-PORT_FWD_UPLINK: Port GigabitEthernet0/2 in vlan 49 moved to Forwarding (UplinkFast).
140192: Apr 30 07:20:23: %SPANTREE_FAST-6-PORT_FWD_UPLINK: Port GigabitEthernet0/2 in vlan 33 moved to Forwarding (UplinkFast).
140193: Apr 30 07:20:23: %SPANTREE_FAST-6-PORT_FWD_UPLINK: Port GigabitEthernet0/2 in vlan 1 moved to Forwarding (UplinkFast).

6 REPLIES
Hall of Fame Super Blue

Re: UPLINKFAST

Is it possible, that the uplinkfast ist triggered by an other event? Any ideas?

Not as far as i know because uplinkfast can only be used when the link has failed. With uplinkfast the blocked link is immediately transitioned to forwarding so the original link would have to have failed otherwise a loop in your network could occur if both links were still active.

Perhaps the trunk port flapped, perhaps you are not logging it. Could also be a bug, perhaps worth checking bug toolkit for your IOS.

Jon

New Member

Re: UPLINKFAST

Hi,

so we didn´t change the logging configuration I think we are logging all messages.

A Link up down of a user ports is logged so the uplink (trunk) up and down is supposed to be logged too.

Checking the bugtoolkit for 12.05wc9 I can´t find a matching bug. Some descripe some uplinkfast bugs....but not this behaviour.

So the IOS is not the latest, perhaps an upgrade will solve the problem nevertheless?

Wolfgang

New Member

Re: UPLINKFAST

Hi,

I activated debug spantree on the switch:

And that´s what I see. The Uplinkfast was triggered by a expiration of the max-age timer....good to know.

141214: May  3 17:30:39: ST: Max-age timer has expired on port GigabitEthernet0/2 vlan 37
141215: May  3 17:30:39: ST: GigabitEthernet0/2 vlan 37 -> blocking (uplinkfast)
141216: May  3 17:30:39: %SPANTREE_FAST-6-PORT_FWD_UPLINK: Port GigabitEthernet0/1 in vlan 37 moved to Forwarding (UplinkFast).
141217: May  3 17:30:39: ST: sent Topology Change Notice on GigabitEthernet0/1 vlan 37
141218: May  3 17:30:39: ST: GigabitEthernet0/2 vlan 37 -> listening

141256: May  3 17:30:41: ST: Heard root 49152-0003.6b8d.9145 on GigabitEthernet0/2 vlan 37
141256: May  3 17:30:41: ST: Heard root 49152-0003.6b8d.9145 on GigabitEthernet0/2 vlan 37
141258: May  3 17:30:41: ST: Topology Change rcvd on GigabitEthernet0/2 vlan 37
141259: May  3 17:30:41: ST: sent Topology Change Notice on GigabitEthernet0/1 vlan 37
141291: May  3 17:30:46: ST: sent Topology Change Notice on GigabitEthernet0/2 vlan 37
141292: May  3 17:30:46: ST: GigabitEthernet0/1 vlan 37 -> blocking
141293: May  3 17:30:46: ST: GigabitEthernet0/1 vlan 37 -> blocking (uplinkfast)
141294: May  3 17:30:46: %SPANTREE_FAST-6-PORT_FWD_UPLINK: Port GigabitEthernet0/2 in vlan 37 moved to Forwarding (UplinkFast).


So next question why does the maxage timer timeout?

Wolfgang

Re: UPLINKFAST

I activated debug spantree on the switch:

And that´s what I see. The Uplinkfast was triggered by a expiration of the max-age timer....good to know.

141214: May  3 17:30:39: ST: Max-age timer has expired on port GigabitEthernet0/2 vlan 37
141215: May  3 17:30:39: ST: GigabitEthernet0/2 vlan 37 -> blocking (uplinkfast)
141216: May  3 17:30:39: %SPANTREE_FAST-6-PORT_FWD_UPLINK: Port GigabitEthernet0/1 in vlan 37 moved to Forwarding (UplinkFast).
141217: May  3 17:30:39: ST: sent Topology Change Notice on GigabitEthernet0/1 vlan 37
141218: May  3 17:30:39: ST: GigabitEthernet0/2 vlan 37 -> listening
141256: May  3 17:30:41: ST: Heard root 49152-0003.6b8d.9145 on GigabitEthernet0/2 vlan 37
141256: May  3 17:30:41: ST: Heard root 49152-0003.6b8d.9145 on GigabitEthernet0/2 vlan 37
141258: May  3 17:30:41: ST: Topology Change rcvd on GigabitEthernet0/2 vlan 37
141259: May  3 17:30:41: ST: sent Topology Change Notice on GigabitEthernet0/1 vlan 37
141291: May  3 17:30:46: ST: sent Topology Change Notice on GigabitEthernet0/2 vlan 37
141292: May  3 17:30:46: ST: GigabitEthernet0/1 vlan 37 -> blocking
141293: May  3 17:30:46: ST: GigabitEthernet0/1 vlan 37 -> blocking (uplinkfast)
141294: May  3 17:30:46: %SPANTREE_FAST-6-PORT_FWD_UPLINK: Port GigabitEthernet0/2 in vlan 37 moved to Forwarding (UplinkFast).


So next question why does the maxage timer timeout?

Wolfgang

Hi Wolfgang,

MaxAge Timer is a Spanning-Tree Protocol (STP) timer that defines how long a bridge or switch should wait after the last received hello message before believing that the network topology has changed, and it can no longer hear the hello messages sent by the root bridge or switch. The MaxAge timer specifies the lifetime of a stored BPDU received on a designated port. After the timer expires, other ports can become designated ports.

Hope to Help !!

Ganesh.H

New Member

Re: UPLINKFAST

Hi Ganesh.h,

yes that´s what I already know.

Now I´m looking for the reason the timer timed out. Under normal circumstaces this should not happen because the root sends BPDUs every 2 seconds. So there is no log according to a link fail oder down...I´m searching the fault.

Does the root bridge send BPDUs?

Does the Switch in front of the switch with this beaviour forward the BPDUs?

I guess there exist a problem with the hardware. Is there a Module, GBIC, Fiber which is responsible?

This error is accuring nearly 1 to 2 times a day.

Wolfgang

Hall of Fame Super Blue

Re: UPLINKFAST

escswosp wrote:

Hi Ganesh.h,

yes that´s what I already know.

Now I´m looking for the reason the timer timed out. Under normal circumstaces this should not happen because the root sends BPDUs every 2 seconds. So there is no log according to a link fail oder down...I´m searching the fault.

Does the root bridge send BPDUs?

Does the Switch in front of the switch with this beaviour forward the BPDUs?

I guess there exist a problem with the hardware. Is there a Module, GBIC, Fiber which is responsible?

This error is accuring nearly 1 to 2 times a day.

Wolfgang

Wolfgang

That would explain why uplinkfast is being activated ie. the switch in question is not receiving BPDUs within the maxage timer and so thinks the link has failed and switches over to the new link.

Yes the root switch does send BPDUs and yes intermediate switches will forward those BPDUs on.

If you are absolutely sure the link is not failing then check for interface errors on the switch port and if you suspect a hardware issue it may be worth replacing the GBIC and possibly the fiber if possible.

Jon

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