Quote: "They'd be much better off switching to FreeBSD since its known to have the fastest IP stack in existence, hence why its used for high end networking gear. Let me know when you see your BigIP running something other than FreeBSD."
F5 has been placing their traffic management software on top of Linux for years.
[root@f5-x:Active] config # uname -a ; rpm -qi tmsh | grep Vendor
Linux f5-x.corp.local 2.6.18-164.11.1.el5.1.0.f5app #1 SMP Thu Apr 8 19:23:04 PDT 2010 x86_64 x86_64 x86_64 GNU/Linux
Version : 10.2.0 Vendor: F5 Networks, Inc.