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F5 LoadBalancer - wam-tcp-wan-optimized Profil


Hi guys,


We have set for one of our Pool the "wam-tcp-wan-optimized" for Protocol Profile (Client) to solve instable downloads and connections from far remote locations (from Internet) => Pb solved


=> BUT my concern is that since we have set this option, some of our company WIN7 laptops are not able anymore to download files internally (from LAN : reduced download speed and failures at the end)) BUT some other WIN7 laptops still able. The roll-back fix this issue (set to "default" instead of "wam-tcp-wan-optimized") but remote connections are not possible.


So my investigation is to compare the differences between "Default" and "wam-tcp-wan-optimized" This is the result :


  • Proxy Buffer Low from 32768 bytes (default) to 98304 bytes (wam-tcp-wan-optimized)
  • Proxy Buffer High from 49152 bytes (default) to 131072 bytes (wam-tcp-wan-optimized)
  • Initial Congestion Window Size from 0 byte (default) to 16 bytes (wam-tcp-wan-optimized)
  • Initial Receive Window Size from 0 byte (default) to 16 bytes (wam-tcp-wan-optimized)

I'm interested to know what are the differences from one non-functional laptop (internally) and a functional laptop (internally) related to the fourth mentionned setup.


Is there anyone here, that already faced this issue ? Have you a got an idea of which conf at client level makes this behavior difference ?


PS, excuse my poor english, and the lack of details, don't hesitate to ask me question. See ya !



Historic F5 Account

As the BIG-IP is a full proxy there's actually two tcp profiles to consider - server facing and client facing. In general, server side gets a LAN (low latency & no congestion) profile and client side would get the WAN profile (higher latency and a better chance of congestion). To start with, I would consider building two virtual servers; one for internal connections LAN/LAN and one for external connections (LAN/WAN) for server/client connectivity.


If you haven't already, read everything on DevCentral by Martin Duke. In particular:




Of course, tuning the BIG-IP is only part of the solution, tuning the server (pool members) and potentially your client systems can have dramatic results.