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Switch as a hub?

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SANDBOX

IS-IT--Management
May 1, 2002
2
US
Hello,

I am new to this so sorry if this should be common knowledge. I would like to know if it is possible to configure a switch as a hub? I have an accelar 1150 that I just need to configure as a fiber hub. I am implementing Windows Load balancing and need all the packets to go to all(or two if possible) ports. The problem I have is, I think the switch is 'learning'(like it should) which ports to send the packets out. Is there a way to flood all the switch ports? or keep it from learning? Both nodes have the same MAC so I am not sure how it learns where to send the packets unless it just retries out the last port it found it on.

I have this working on ethernet so I know I have everything else configured correctly.

Thanks for the help!
 
You can place all of the ports in the same vlan but if the devices are the same mac addresses this will create a loop.
Another solution is to use MLT multilink trunking for this connection, providing the network interface card supports this.
 
You may wish to read up on port mirroring, sending all the I/O from one port to another port. if you are just wanting to load balance input, it may work. Multi Link Trunking is what I use to my server, but it is not always implemented the same amoung vendors. I tried to remain child-like, all I acheived was childish.
 
Hello!

Windows Load Balancing, on W2000, does not work like you say. When load balancing two, or more, servers, they gets each their mac address, a virtual adress. But, they responds two a third address, which is the same for both. When a router, or a firewall, is doing a ARP request, the servers responds from their own mac address, that the router/firewall, should use the third mac address when sending packets to the servers. By doing this, the switch never gets a packet from the third mac address, and will not have it in the forwarding table, and all traffic to the servers, are flooded over all the ports in the VLAN. Because of this, you only have to put all the ports in the same VLAN, and Windows does the rest!

Or, you could use Nortel Alteon switches, which are a load balancing switch!

GT
 
Thanks all,

What packets route between VLAN's by default? Is routing between VLans done at layer 2 or layer 3?

I was attempting to do this in unicast mode, but have not been able to come up with a solution. Gtomte, I have changed to mulitcast and created a seperate VLan for the ports. Access from our other VLan is intermittent. I believe it goes to the first node to come online and once the wlbs service is stopped or started it won't come back online. I have looked at the arp table on the switch and it shows the virtual address on only one port in the new Vlan? Should this source address be masked? How can I get all packets to go out all ports?

Sorry so long winded. Thanks for your suggestions.

Brian
 
Hello!

This is from a Microsoft document:
However, most level-2 switches require that each port be associated with a unique source media access control address. Network Load Balancing addresses this requirement in unicast mode by enabling the MaskSourceMAC feature by default.

Check:

This explains how you can make it work with unicast, and layer 2 switches.

A switch forwards on layer 2, and routes on layer 3.

GT
 
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