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etherchannel 3550

I would need some help with the following:

I am using a 3550-12T switch, two Gigabit ports are connected to one server in etherchannel, load is distributed equaly between the two links! (mainly it is done by the server because 95% of the traffic is outgoing from the server). there are other 2 ports connected to a 4948 switch, configured in etherchannel. the problem is that 3550 knows only dst-mac or src-mac type of load balancing and nothing else. because the traffic is originating from one etherchannel, it is only one MAC address... the clients are connecting via WAN, so as they are routed I send all the traffic to the router, which is again one MAC address. basically none of the 2 available load balancing options works. do you know about any possible solution?

Thanks

Imre

2 REPLIES
Purple

Re: etherchannel 3550

Not sure if there is a answer to this or not , here is the info right outof the 3550 guide.

Understanding Load Balancing and Forwarding Methods

EtherChannel balances the traffic load across the links in a channel by randomly associating a newly learned MAC address with one of the links in the channel.

With source-MAC address forwarding, when packets are forwarded to an EtherChannel, they are distributed across the ports in the channel based on the source-MAC address of the incoming packet. Therefore, to provide load balancing, packets from different hosts use different ports in the channel, but packets from the same host use the same port in the channel (and the MAC address learned by the switch does not change).

When source-MAC address forwarding is used, load distribution based on the source and destination IP address is also enabled for routed IP traffic. All routed IP traffic chooses a port based on the source and destination IP address. Packets between two IP hosts always use the same port in the channel, and traffic between any other pair of hosts can use a different port in the channel.

With destination-MAC address forwarding, when packets are forwarded to an EtherChannel, they are distributed across the ports in the channel based on the destination host's MAC address of the incoming packet. Therefore, packets to the same destination are forwarded over the same port, and packets to a different destination are sent on a different port in the channel. You configure the load balancing and forwarding method by using the port-channel load-balance global configuration command.

In Figure 29-3, multiple workstations are connected to a switch, and an EtherChannel connects the switch to the router. Source-based load balancing is used on the switch end of the EtherChannel to ensure that the switch efficiently uses the bandwidth of the router by distributing traffic from the workstation across the physical links. Since the router is a single MAC address device, it uses destination-based load balancing to efficiently spread the traffic to the workstations across the physical links in the EtherChannel.

Use the option that provides the greatest variety in your configuration. For example, if the traffic on a channel is going only to a single MAC address, using the destination-MAC address always chooses the same link in the channel; using source addresses or IP addresses might result in better load balancing.

New Member

Re: etherchannel 3550

Thanks!

I already tried both types of the available methods, but as both ends are single mac addresses, one end is the router connected with 2x1GE, the other end is a server connected with 2x1GE... I am thinking on that maybe the solution would be something other then etherchannel towards the router, but I have no experience on this field, and didn't really find anything which would help me.

Thanks

Imre

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