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New Member

Flapping port connected to Dell NIC team

Hello,

I've plugged 2 ports from a Dell server that are teamed and the switch console keeps saying both ports are flapping, what does this mean?  Both ports at both ends are configured as speed 1000 and full duplex.

I haven't got access to the switch while I type this, but I know the ports have the following enabled:

spanning-tree portfast

flowcontrol receive on

The Dell NICs are configured with jumbo frames (mtu 9000)

The switche is a 3750G.

Any ideas what coudl be causing this issue?

  • LAN Switching and Routing
5 REPLIES
Green

Flapping port connected to Dell NIC team

Andy,

Is team set up for load balancing or fault tolerance ?

Is the team using LACP ?

Have you set up the 3750 ports as a port channel ?

Regards,
Alex.
Please rate useful posts.

Regards, Alex. Please rate useful posts.
New Member

Flapping port connected to Dell NIC team

Hello,

We've tried all the different modes on the card but still get the same flapping errors.  Dell said we don't need to set anything on the Cisco switch as the Dell NIC should do all the work, maybe we need to?

Green

Flapping port connected to Dell NIC team

Andy,

Sorry for the delay

Lets assume that the server lives on Vlan 25. And that ther
switches are stacked so Im using ports G1/0/1 & G2/0/1

For fault tolerance mode ( Worker/Standby)

!
int Gi1/0/1
shut
desc  *** SeRver Eth 1 ***
switchport host
switchport access vlan 25
no shut
!
!
int Gi2/0/1
shut
desc  *** SeRver Eth 2 ***
switchport host
switchport access vlan 25
no shut
!


For fault Network Load Balancing mode ( Worker/Worker)

This will automatically buils the ether channel ( I have used 25 to
match the VLAN)

!
int Gi1/0/1
shut
desc  *** SeRver Eth 1 ***
switchport access
switchport access vlan 25
channel-group 25 mode active
spanning-tree portfast
no shut
!
!
int Gi2/0/1
shut
desc  *** SeRver Eth 2 ***
switchport access
switchport access vlan 25
channel-group 25 mode active
spanning-tree portfast
no shut
!

Hope this helps

Regards,
Alex.
Please rate useful posts.

Regards, Alex. Please rate useful posts.
Silver

Flapping port connected to Dell NIC team

channel-group 25 mode active

this means LACP, is LACP enabled on Dell side?

Check

show etherchannel summary

Silver

Flapping port connected to Dell NIC team

Hi, is it solved?

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