First, note that in general there is 32K of memory used per session. There is no difference between a tunnel and a session. 2,000 tunnels of one session each or one tunnel with 2,000 sessions in it consumes roughly the same resources.
Here are some numbers from a real customer's network:
7200, NPE-150 w/ 11.3(7.5)AA, 13 L2F tunnels 552 sessions, 26% CPU
7200, NPE-150 w/ 11.3(7.5)AA, 14 L2F tunnels 629 sessions, 60% CPU
7200, NPE-200 w/ 11.3(7.5)AA, 17 L2F tunnels 1001 sessions, 38% CPU
7206VXR, NPE-300, 12.0(5)T1, 14 L2F tunnels 780 sessions, 26% CPU
In lab, the 7200 has been tested with OC3 line rate with 8,000 PPP sessions and 1,000 L2TP tunnels with NPE-400 , 512MB of RAM and 12.1(5)T. This assumes
proper configuration (including potential buffer tuning), which may be critical to achieving these results.
