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J Collins
Asked: 2014-11-21 06:04:03 +0800 CST

Multilayer LACP

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I have a network switch that is limited to 2x1Gb/s LACP teaming, however have a file server with a 4x1Gb/s network interface. What options do I have to aggregate all available bandwidth without needing arbitrary walls between bandwidth or connections?

One thought was to create two teamed pairs, then create a team of those two, but I might be dreaming. Alternately, can the file server machine simply exist on the network as two IP addresses and use a software solution for load balancing across both links.

I am only just starting in the world of networking and probably have a lot to learn, it just seems like there must be some solution that could use all of the available bandwidth, despite the switch hardware limitation.

Edit:

I am flexible with the operating system as it is a new configuration, however the options do not include any versions of Windows Server. Most likely it will be a Linux distribution such as FreeNAS.

The server NIC is an HP NC364T and the switch an HP ProCurve 1910-48G.

Edit 2:

Another idea, could the two pairs be configured as two uni-directional halves of a full-duplex connection?

networking

2 Answers

  1. I think you need to get a switch which can have 4 ports in an LACP aggregation.

    Be aware that SMB file sharing will mean one TCP session to one IP address, so you'll need to load balance based on IP, and each client will be load balanced to a specific NIC.

    You'll need to configure IP-based load balancing on both the Windows system and the switch.

    Some OSes support TCP-port-based load balancing, though this is not compliant with 802.3ad.

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  2. I doubt you can, but in your edit 2 where you mention splitting the two teams as two half-duplex parts of a full duplex connection, we wary of doing that as it could potentially open you up to a single point of failure depending upon how the links are configured.

    suprjami is probably right though, it's probably easiest to just upgrade the switch to something that supports more than 2x1Gb LACP. He's also spot on about pointing out that a single session will never use more bandwidth than a single link in the LACP trunk can provide, so in a 4x1Gb or 2x1Gb LACP configuration, individual sessions will be limited to 1Gb. That's not necessarily a problem if you're trying to service a bunch of clients, but if you have a single client and are trying to get 2Gb of throughput to it, it won't work that way.

    If you must have 4Gb, I'd look at setting up a pair of 2x1Gb LACP trunks and giving each one it's own IP. Then you could do something like round robin DNS for that server's hostname. It wouldn't give you a perfect bandwidth distribution but it's a relatively easy and simple solution that would get you more than what you've got now.

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