[GLLUG] VPN question expanded: latency

[Paul Donahue]

During the presentation I recall the question about latency issues associated with VPNs. I said it was usually negligible. Well I have some more details on it from a little test I am running currently:

Computers involved:
- P133, 48MB ram running Debian Woody w/ FreeSWAN 1.96 connected to ACD.net DSL
- 1GHZ Windows 2000 connected to 100Mbit FDX w/ IPSEC connecting to home VPN
- 550Mhz WinXP connected to 100Mbit HGX no ipsec, just straight internet connection

Ping times:
- from win2k -> vpn hosts: ~60ms
- from winxp -> outside network (no encryption): ~56ms

so you're getting about a 4ms latency using the encryption. I personally feel this is mostly negligible as windows considers anything < 10ms not worth metering. Basically... don't use it on gigabit or straight 100Mbit - 100Mbit if you're worried about speed. If you have a 100Mbit pipe into your house/remote site I wanna be your friend :)

Hope this helps out.


Paul Donahue
Computer Scientist
Computer/Network Technician
Michigan State University
http://www.pdonahue.com/
ICQ: 1624723   Phone: 517-204-6047