Introduce Iain B. Findleton's great report of his gigabit-link observations.. See Tcl Socket Performance.
Mention Microsoft explanation [L1 ] of its networking fault.
Point to more general page on Tcl Performance.
See also Todd Corams Idoms: Building High Performance Networking Servers using Tcl [L2 ]
Also, there's a dual consideration of networking impacts on Tcl performance; explain DNS faults and so on.
This [L3 ] book review is likely to interest many readers.