Is D-Link compatible with Macbook?

Is this a switch or a router? Do you have a router?

Unless your modem is also a router the switch cannot be used to share an internet connection, hence only one computer can be used at the same time with the switch. To share the internet connection you must have a router connected to the modem.

A router is a hardware device that you connect to your cable/DSL modem. When you connect multiple computers to it the router automatically assigns each computer a separate "local" IP address. When each computer accesses the internet the router provides the computer with a proper connection to the 'real" IP address provided by your ISP through the modem. Each computer "appears" to be connected to the same IP address - hence it's called sharing. The router uses a Network Address Translator or NAT to accomplish this task. Any IP device - computers, printers, etc. - can talk or share information with others on the same network. Everything is handled by the router.

A switch is simply a device that enables more devices to be connected to a router than the number of ports the router would normally provide. If your router had four Ethernet ports - usually called the LAN ports or Local Area Network ports - but you needed to connect more than four devices, then a switch can be connected to one of the router's LAN ports. A four port switch would add three or four additional ports to the router but use only one port on the router.

See the following article: Network Switch. Here's a somewhat technical discussion about the differences between routers and switches.

If your modem has only one Ethernet port to connect the modem to the computer, then you need a router if you want both computers to have internet access. Unfortunately, you haven't told us anything about the modem make and model, so only you know if it is simply a modem or a modem/router.

That is not a modem/router. I have a slightly later model but it looks exactly the same. If you plan to share the internet connection, then I recommend buying a compatible router. D-Link makes a number of good routers although D-Link is not renown for their "open" Mac support. They leave you pretty much on your own as all their software is for Windows. Fortunately, their routers can be setup and configured through any web browser such as Safari.

Now personally i'd recommend Apple's Airport Extreme Base Station ($179) but if you're not inclined to spend that then you could use a D-Link router or a LinkSys router if that's your preference. Most all routers will work with Macs. I've used the D-Link **-524 router (wired and wireless) successfully with Macs, but it's older and does not support the new 802.11n faster wireless speed nor does it support Gigabit Ethernet. But later D-Link models should.

At my Florida home I use an Airport Extreme Base Station. In Canada I use the D-Link I mentioned above. I did have to update it's firmware a couple of times, and D-Link does not provide the software to do that on a Mac, but it can be done from any Windows computer (doesn't take too long.)