Every computer needs an IP address (which looks something like 192.168.0.10) to access the Internet. Normally, the network driver obtains that address automatically over the network with a service such as DHCP (dynamic host configuration protocol), unless it is assigned manually as part of the configuration.

With an external Ethernet DSL modem, there can be a problem if PPPoE software creates its own connection with its own IP address, leaving the Ethernet network driver in the lurch. By default, the Ethernet network adapter driver may keep trying to find a DHCP server. Unfortunately, consumer versions of Microsoft Windows pretty much come to a halt while the network driver is waiting for a DHCP server to respond (until the attempt times out).

If you experience such periodic pauses, and you have an Ethernet adapter with Windows, try assigning a private network address (such as 192.168.0.10, with a Subnet Mask of 255.255.0.0) to TCP/IP for your Ethernet adapter. (Control Panel/Network/Configuration/TCP/IP/Your Ethernet Adapter/Properties/IP Address.)