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I was hoping to find a way to increase bandwidth between two desktop switches I have, and I wondered if connecting them with two cables (or perhaps three) instead of just one might increase theoretical bandwidth (which I am currently not in danger of saturating yet anyways)

From this question (2 ethernet connections between two Switches), I kind of assume I can't do what I hope to do, but I would love specific confirmation.

I assume typical cheap desktop switches would be unmanaged and thus useless and/or self-defeating when connecting them with more than one cable and trying to create a little more bandwidth between them.

Is this one of the differences between managed and unmanaged switches? And if I had managed switches, would it work (connect them with two cables to essentially double the bandwidth)?

Community
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Code Jockey
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4 Answers4

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An unmanaged switch won't have the feature you're looking for and connecting two ports between both switches will create a switch loop, which will effectively render the switches and the network unusable.

A managed switch should have the feature that you're looking for, which is called Link Aggregation (LAG). Before purchasing a managed switch make sure to verify that it does indeed support LAG.

joeqwerty
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    I had a Netgear switch once that put the LAG settings under the "trunking" menu. Caused a might of confusion. We almost returned it before finding the settings - so yes, be sure! – Mark Henderson May 08 '13 at 22:01
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    I find it quite humorous that we want "LAG" as a feature in this case. ;) – CyberSkull May 10 '13 at 08:02
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Yes, you can do this, if both switches support link aggregation (which goes by a variety of names such as bonding, NIC teaming, port trunking, etc.). You're unlikely to find this feature in consumer grade hardware or unmanaged switch.

The answer to the question you referred to even specifically mentioned LACP, one common protocol for link aggregation.

Michael Hampton
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    You'd be surprised how many consumer grade switches support LACP nowadays. You can get LACP, VLANs, mirroring and lots of other features for less that USD100. – Gerald Combs May 08 '13 at 20:07
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The open source router firmware DD-WRT appears to support link aggregation; if you're lucky enough to have bought hardware compatible with it then you could re flash the OEM firmware to DD-WRT to gain the feature.

Be warned that doing so is warranty voiding; and if something goes wrong you can brick your hardware so caveat emptor. Doing this will also require you to learn a new admin interface that's (of necessity) more complex than most consumer grade devices because it exposes so many more options, and reprogram any custom settings/rules you had in the hardware before switching it over.

However this is probably just a stopgap even if it works; while DD-WRT can give you a lot of the advanced features normally only available with enterprise networking hardware the chips controlling it are still only consumer grade and generally have significantly lower performance caps.

Dan Is Fiddling By Firelight
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There is a great Linksys article talks about this matter.
All the switches and NICs must support Link Aggregation of any kind for it to work properly.

Slavik Meltser
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