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Community Member

Core 4500 series Hostflapping host 02:01:00:00:00:00

I have I deal of broadcast undesired in Core 4505, hostflapping between two interfaces, and possibly the communication to be affected, in the core the message are 313662: *Aug 14 06:46:24: %C4K_EBM-4-HOSTFLAPPING: Host 02:01:00:00:00:00 in vlan 10 is flapping between port Gi3/1 and port Gi1/1, activates to sniffer for monitorear deals and obtained the following message 0x886f: MS NLB heartbeat, that I can do?

Angel Alvarez

Caracas, Venezuela

1 ACCEPTED SOLUTION

Accepted Solutions
Hall of Fame Super Bronze

Re: Core 4500 series Hostflapping host 02:01:00:00:00:00

Often when seeing hostflapping messages between 2 ports means that the device connected to those 2 ports is advertising the same MAC Address. Verify the device connected in G3/1 and G1/1 and check for configuration such as load balancing or teaming software.

You may need to configure etherchanneling in your end to correct those messages.

Please rate helpful posts.

Thanks

Edit:

Based on the information provided by vijayasankar, you need to configure etherchanneling on those ports, for instance:

interface g3/1

channel-group 1 mode on

interface g1/1

channel-group 1 mode on

5 REPLIES
Hall of Fame Super Bronze

Re: Core 4500 series Hostflapping host 02:01:00:00:00:00

Often when seeing hostflapping messages between 2 ports means that the device connected to those 2 ports is advertising the same MAC Address. Verify the device connected in G3/1 and G1/1 and check for configuration such as load balancing or teaming software.

You may need to configure etherchanneling in your end to correct those messages.

Please rate helpful posts.

Thanks

Edit:

Based on the information provided by vijayasankar, you need to configure etherchanneling on those ports, for instance:

interface g3/1

channel-group 1 mode on

interface g1/1

channel-group 1 mode on

Community Member

Re: Core 4500 series Hostflapping host 02:01:00:00:00:00

thank you very much Edison, however if I make east change:

interface g3/1

channel-group 1 mode on

interface g1/1

channel-group 1 mode on

it affects the sevice?

that it makes east change in the configuration?

Hall of Fame Super Bronze

Re: Core 4500 series Hostflapping host 02:01:00:00:00:00

No, it won't affect affect the service.

Currently the ports are alternating from blocking to nonblocking hence the term hostflapping.

The switch can only have one exit port associated to a MAC address. With Etherchanneling, you are grouping those 2 ports into 1 port-channel.

Please rate helpful posts.

Thanks

Re: Core 4500 series Hostflapping host 02:01:00:00:00:00

Hi,

This is the way Microsoft NLB solution works by default.

If you are using the nlb settings, then possibly it is working in NLB unicast mode.

There is also an option available in microsoft to deploy NLB in multicast mode.

When deployed in NLB Unicast mode, All cluster member Hosts are assigned the same MAC address. The disadvantage of this mode of operation as mentioned by microsoft is as follows,

1) Unicast mode induces switch flooding, where all switch ports are flooded with NLB traffic, even ports to which non-NLB servers are attached;

You can get more information from microsoft site in the following URL

http://technet2.microsoft.com/WindowsServer/en/library/884c727d-6083-4265-ac1d-b5e66b68281a1033.mspx?mfr=true

HTH

-VJ

Community Member

Re: Core 4500 series Hostflapping host 02:01:00:00:00:00

thank you very much, the information is of much aid, then the communication was affected by this flood of packages and not by problems of configuration of the network?

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