Web Caching

Port Numbers

Recall that interception caching (Chapter 5) usually diverts only port 80 connections. However, some HTTP servers use other ports for various reasons. The IRCache data in Table A-9 shows that only 0.3% of HTTP traffic is not on port 80. However, this is an underestimation if we assume that many of the IRCache clients use interception proxying to begin with. The non-port 80 requests won’t be intercepted and hence won’t reach these caches.

Table A-9. Server Port Numbers (IRCache Data)

Port	% Servers	% Requests	% Bytes
80	99.705	99.610	99.619
8080	0.003	0.088	0.094
8000	0.003	0.039	0.040
All others	0.289	0.262	0.247