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New Member

MAC flapping

Hi,

I have a problem with MAC flapping on one of my switches. I didn't setup that environment and I founded that recently. I think person which was in company before made there mistake with configuration.

Below here is a picture how it is connected. Basically from server to switch there is 2 cables going and they are using the samne VLAN.

ScreenShot149.png

On the picture I pasted config of switchports and output from syslog.

What I'm thinking is to make this two switchport in one EtherChannel using channel-group command. What do You think ??

Best Regards, Jacek

Everyone's tags (1)
2 ACCEPTED SOLUTIONS

Accepted Solutions
Silver

Re: MAC flapping

Well, I think that etherchannel with "mode on" should work in this kind of environment...give it a try. Also, check on this link if everything about bonding is OK with your linux:

http://www.charleshooper.net/blog/link-aggregation-on-a-redhat-centos-server-and-a-cisco-catalyst-switch

It's for CentOS but I suppose it's similar for every other Linux...

I suppose you know how to configure etherchannel on Cisco side...

HTH,
Dragan

HTH, Dragan

Re: MAC flapping

Hello

Etherchannel would be a good way to proceed using LACP (channel-mode active) however, in the meantime remove portfast from the access ports and let stp negociate.

res

Paul

Please don't forget to rate any posts that have been helpful.

Thanks.

Please don't forget to rate any posts that have been helpful. Thanks.
5 REPLIES
Silver

MAC flapping

That should be great if your server environment with NICs on it support etherchannel - virtual hypervisor support that with their virtual switches, everything else you typically need NIC vendor software with options to configure etherchannel...

HTH,
Dragan

HTH, Dragan
New Member

Re: MAC flapping

It is a typical Dell server and it has bond setup:

[jtymoczko@lsrv02 ~]$ sudo /sbin/ifconfig

bond1     Link encap:Ethernet  HWaddr 00:1B:21:47:2A:FC

inet addr:172.21.21.1  Bcast:172.21.21.3  Mask:255.255.255.252

inet6 addr: fe80::21b:21ff:fe47:2afc/64 Scope:Link

UP BROADCAST RUNNING MASTER MULTICAST  MTU:1500  Metric:1

RX packets:382319127 errors:0 dropped:0 overruns:0 frame:0

TX packets:373617301 errors:0 dropped:0 overruns:0 carrier:0

collisions:0 txqueuelen:0

RX bytes:57752960147 (53.7 GiB)  TX bytes:57012937617 (53.0 GiB)

Silver

Re: MAC flapping

Well, I think that etherchannel with "mode on" should work in this kind of environment...give it a try. Also, check on this link if everything about bonding is OK with your linux:

http://www.charleshooper.net/blog/link-aggregation-on-a-redhat-centos-server-and-a-cisco-catalyst-switch

It's for CentOS but I suppose it's similar for every other Linux...

I suppose you know how to configure etherchannel on Cisco side...

HTH,
Dragan

HTH, Dragan

Re: MAC flapping

Hello

Etherchannel would be a good way to proceed using LACP (channel-mode active) however, in the meantime remove portfast from the access ports and let stp negociate.

res

Paul

Please don't forget to rate any posts that have been helpful.

Thanks.

Please don't forget to rate any posts that have been helpful. Thanks.
New Member

Re: MAC flapping

Thanks guys,

Next week I have planned maintenance window and I'm planning to introduce EtherChannel on that.

We will see how it works.

BR, JT

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