[Cadaver]

Anyone know if OS X can do load balancing (not just fail-over) if two ethernet ports/connections are available?

I have two separate 100Mbit network connections in my office, both with University network access. No idea of peak bandwidth, other than "lots."

If I add a second ethernet card to my Mac, can I configure OS X (client) to take advantage of this extra pipe? I run a semi-private image server off that particular Mac (simple URL comes in, large DICOM medical image files go out), and the extra outgoing bandwidth would be great.

[pat++]

If people are using the name of your Mac in the URL to access the server, you could ask your network admin to add the 2 ip of your Mac (one for each ethernet card) in the dns, and associate them with the same name. DNS server usually use the 2 ips randomly when 2 ips are associated with the same name. This way, 2 requests on your machine could be randomly routed to one ethernet card or the other.

[larkost]

I hate to burst your bubble, but unless you have two completely separate networks, plugging into two jacks is not going to get you any more bandwidth. And the chances that you have two separate networks are very small indeed.

In all likelihood you have two jacks in your room that lead to the same hub or switch, so you could get (theoretically) double the bandwidth to that device, but it still has a limited amount of bandwidth available to the next device, and in most University settings, that bandwidth is either 10Mbit (more likely in many places) or 100Mbit. And I am completely ignoring that that hub/switch has internal bandwidth limitations (referred to as the backplane bandwidth).

Executive summary: don't bother unless you are a very knowledgeable network admin.

PS... just to head off a question about what speed your whole network is: Many Universities have 100Mbit networks in each building, but then 10Mbit links connecting the buildings. Often newer buildings will have gigabit connections between the internal switches, 100Mbit to the clients, and a 100Mbit connection to network services (who might have an OC connection to the outside world).

Long runs of 100Mbit cable can get very expensive (repeaters, etc). 10Mbit is so much cheaper.

[Cadaver]

Hmmm.... I know for a fact that we have gigabit links to the closet switches and 100Mbit to the offices. Will 2x100Mbit lines to the switch not result in a bigger chunk of that bandwidth available to me?

[Millennium]

Originally posted by Cadaver:
Hmmm.... I know for a fact that we have gigabit links to the closet switches and 100Mbit to the offices. Will 2x100Mbit lines to the switch not result in a bigger chunk of that bandwidth available to me?

Only as far as the switches go. Without more details on your network topology there's no way to know if there are any bottlenecks. If there's a bottleneck further down the pipe, then extra lines are not going to help you, no matter how many you add.

By the way, I would seriously not do this. Aside from being extremely rude, your job could be in very real danger if they catch you doing this. This falls way outside of most place's acceptable-network-use policies. What the heck do you need another line for, anyway?

[coolmacdude]

Originally posted by Millennium:
By the way, I would seriously not do this. Aside from being extremely rude, your job could be in very real danger if they catch you doing this. This falls way outside of most place's acceptable-network-use policies. What the heck do you need another line for, anyway?

One of the reasons almost all Unis are starting to go over to MAC address encryption for each port.

[sbjordal]

Originally posted by Cadaver:
Anyone know if OS X can do load balancing (not just fail-over) if two ethernet ports/connections are available?

I have two separate 100Mbit network connections in my office, both with University network access. No idea of peak bandwidth, other than "lots."

If I add a second ethernet card to my Mac, can I configure OS X (client) to take advantage of this extra pipe? I run a semi-private image server off that particular Mac (simple URL comes in, large DICOM medical image files go out), and the extra outgoing bandwidth would be great.

If this is a sanctioned server and you're staff, then by all means, talk to your network admin. They can assign you two static IP addresses, and enable Round Robin on the DNS server to point to your computer. The Round Robin setting would determine how often, or how many requests that will be sent to each of your NICs. Ofcourse, you're not mentioning anything about your computer, and it could very well be that the bottleneck will be your computer/server, and not the network. Trust me, talk to someone and get it sanctioned before you plug anything in and mess with it yourself. I've seen people getting fired for less.

[sbjordal]

Originally posted by larkost:
I hate to burst your bubble, but unless you have two completely separate networks, plugging into two jacks is not going to get you any more bandwidth. And the chances that you have two separate networks are very small indeed.

In all likelihood you have two jacks in your room that lead to the same hub or switch, so you could get (theoretically) double the bandwidth to that device, but it still has a limited amount of bandwidth available to the next device, and in most University settings, that bandwidth is either 10Mbit (more likely in many places) or 100Mbit. And I am completely ignoring that that hub/switch has internal bandwidth limitations (referred to as the backplane bandwidth).

Executive summary: don't bother unless you are a very knowledgeable network admin.

PS... just to head off a question about what speed your whole network is: Many Universities have 100Mbit networks in each building, but then 10Mbit links connecting the buildings. Often newer buildings will have gigabit connections between the internal switches, 100Mbit to the clients, and a 100Mbit connection to network services (who might have an OC connection to the outside world).


Long runs of 100Mbit cable can get very expensive (repeaters, etc). 10Mbit is so much cheaper.

Are you talking LAN or WAN here? 10mbit LAN between buildings was common maybe 20 years ago. Most universities would have switched to Fiber between buildings and atleast switched 100 intra-campus by now.

As far as cost of 100 vs 10 mbit, Fiber is usually used to offset cost of repeaters if the distance is even close to reaching maximum( 300 ft) per segment, and the diff. in price between CAT5 and Cat3 is not all that much.

Edit: Spelling

[Cadaver]

My server is authorized, but thank you anyway for your concern about my job. I wouldn't do anything without IT authorization; I first wanted to know if it was possible. Sounds like its technically possible, but unlikely to be of much benefit.
Thanks anyway.