Do I need a managed switch if I do link aggregation?

[hajime]

Hi, under Mac OS Ventura, we could set up link aggregation. Once it is done, do we also need to get a managed, rather than an unmanaged, switch? Is it possible to do it without a switch?

 

[Slartibart]

Once it is done, do we also need to get a managed, rather than an unmanaged, switch?

Yes (There might be one or two unmanaged models with support out there, but in general this requires a managed switch).

Is it possible to do it without a switch?

Yes. If your Mac has 2 (or more) ethernet ports you can connect them to your router and combine them to a single logical connection.

Nota bene: Link aggregation offers clear benefits, particularly in a loaded and congested network. But if you think about to apply this from a purely gaming perspective, it is unlikely to directly increase FPS, or lower latency if the network is less congested (most online gaming uses a relatively small amount of data) - although this constant flow of data, both on the upload and the download is more crucial to an excellent gaming experience, and a direct wired connection with leftover bandwidth facilitates this, especially as the network load increases.

 

[hajime]

Thanks. I plugged in a USB to 2.5GbE adapter to a Mac Mini M2 and under Mac OS, I used Link Aggregation to combine them together into one virtual link. Then, I connected it to a PC. Tried to plug in a CAT6 cable to the built-in 1GbE port of the Mini but no increase in speed. Then, unplugged the cable and connected it to RJ45 port of the 2.5GbE adapter but there was also no increase in speed. If I recall correct, somebody said that I need to use two cables (one connected to the built-in 1GbE port of the Mini and another connected to the 2.5GbE port of the adapter) and then plug the other end of both cables to a switch or router (don't remember which) for Link Aggregation to work. The router is in another room so if the switch can get the job done without connecting it to the router, I just get a switch and put it in the computer room.

 

[mcnallym]

You need to remember that whilst combining 2 x Ethernet Ports into one logical connection then a single connection between 2 PC’s won’t go any quicker.

where becomes quicker is with a server where have two cables going into the server and them link aggregated.

1st client connection uses the 1st cable and 2nd client connection uses the 2nd cable, thus providing faster network connectivity.

however 1 client with 1 connection won’t see a 2gbe connection presuming 2 x 1Gbe connections on the server.

An important concept of link aggregation is that all the packets belonging to any individual session should go down the same single link. Otherwise, you risk out-of-order packets, which causes serious problems for a lot of applications.

thus why if connecting two machines directly then you won’t see any magic increase in speed as you found.

 

[Kgeee]

You need to remember that whilst combining 2 x Ethernet Ports into one logical connection then a single connection between 2 PC’s won’t go any quicker.

where becomes quicker is with a server where have two cables going into the server and them link aggregated.

1st client connection uses the 1st cable and 2nd client connection uses the 2nd cable, thus providing faster network connectivity.

however 1 client with 1 connection won’t see a 2gbe connection presuming 2 x 1Gbe connections on the server.

An important concept of link aggregation is that all the packets belonging to any individual session should go down the same single link. Otherwise, you risk out-of-order packets, which causes serious problems for a lot of applications.

thus why if connecting two machines directly then you won’t see any magic increase in speed as you found.

SMB Multichannel will allow for this, and macOS does support it. But I've never gotten it to work.

 

[mcnallym]

SMB Multichannel will allow for this, and macOS does support it. But I've never gotten it to work.

But SMB Multichannel is NOT link aggregation. It works at a higher level in the stack.

that functionality is provided by SMB not the Link agrregation.

 

[Kgeee]

Interesting. I did not know that.
It seems the NIC must support server side scaling for it to work. Is it possible to get multichannel to work between two macs? I’ve tried it, but never with any success. This was using link aggregation.