Forum Discussion
AltostratusWAN and LAN definition
WAN = High-Latency, and potentially High Packet Loss rates too.
LAN = High bandwidth, low latency == example, Gigabit LAN is high bandwidth, since it's a gigabit per second, and the devices are usually within 100 meters of each other, and so the latency is low too (in addition to being full duplex, which also helps).
the TCP profiles for LAN and WAN just differ in their default settings, usually buffer sizes. You don't need to tweak them unless you understand the knobs you're tweaking, and you know exactly what you hope to achieve.
WAN = High-Latency, and potentially High Packet Loss rates too.
LAN = High bandwidth, low latency == example, Gigabit LAN is high bandwidth, since it's a gigabit per second, and the devices are usually within 100 meters of each other, and so the latency is low too (in addition to being full duplex, which also helps).
the TCP profiles for LAN and WAN just differ in their default settings, usually buffer sizes. You don't need to tweak them unless you understand the knobs you're tweaking, and you know exactly what you hope to achieve.
dragonflymrCirrostratus
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.
- giltjr_32735
Nimbostratus
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. - dragonflymrThanks a lot for answers. I was suspecting something like that but would like to be sure. I wonder what is best practice in evaluating what profile to use for given side of connection. Probably using tcp-wan-optimized on the client side and tcp-lan on server side is not always best option even if looks like most logical? Is there any good sol or other doc that is giving relatively straightforward advises and steps how to test to find best possible settings for profiles and profiles combinations? Piotr
- This is why the profiles are named "LAN" and "WAN". If you have a high-latency but high-bandwidth link, then the WAN profiles will enable a higher theoretical peak throughput per connection. If you have a high-bandwidth low-latency link, it doesn't really matter which one you use, because you will still observe roughly the same performance, however, the WAN profiles tend to use more memory per connection because of the larger buffer sizes. You decide.
