WAN and LAN definition

Hi, So main factors in deciding if given link should be considered WAN or LAN is latency and packet loss rate? I can easily imagine Internet uplink with 1Gbps so same/similar bandwidth as LAN. Piotr

The main factor is latency. Yes, it is of course possible for WAN Links to have just as much bandwidth as LAN links, but it is far more common for LANs to be higher bandwidth, simply because it's dead simple and cheap to get high bandwidth LANs. Latency though, there's usually very little you can do about. Personally, I wouldn't take this too seriously. Like I said, this is just a convention, and not particularly any standard. It's also just a name. You could have a WAN link that is based on optical fibre, and it will have high bandwidth and low packet loss rate, and relatively low latency. You just need to understand the various TCP parameters and how they affect performance, and tune your TCP profile accordingly. The WAN profiles are generally suitable for high-latency links and the LAN profiles for lower latency links.

Also typically on a LAN you have more control if not full control of end-to-end connectivity. Where as on a WAN you don't. Yes you can have a 1 Gb "WAN" uplink to the Internet, but what about the customer that is on a fractional T1 half way around the world with only 256Kbps bandwidth because that is all they can get in their country. In their most basic of means, LAN is Local Area Network, where as WAN is Wide Area Network. So with a WAN the end points are "wide" apart, not local.