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Piotr_Lewandows's avatar
Piotr_Lewandows
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Apr 13, 2015
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WAN and LAN definition

Hi,   I wonder what is main factor in deciding if given connection should be considered WAN or LAN - in relation to for example setting TCP profile for both client and server sides of connection. ...
application delivery
design
LTM
performance
TMOS
  • BinaryCanary_19's avatar
    BinaryCanary_19
    Apr 13, 2015

    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.

     

BinaryCanary_19's avatar
BinaryCanary_19
Historic F5 Account
Apr 13, 2015

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.

 

BinaryCanary_19's avatar
BinaryCanary_19
Historic F5 Account
Apr 13, 2015
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.