I am looking for some delay values so I can do a theoratical calculation for a way from a remote office over an guaranteed ISP delay (e.g 120ms) to the headquarter. The way is going though pix firewalls and different cisco routers (7206,3640,2651).
Are there any informations, how much processing time a router,pix ... needs for forwarding a packet ? Or a switch (switch is not so important, because the values are in nanoseconds). Based on the calculation I want to discuss using VoIP over an QoS-powered ISP or not. Is such a calculation already done ?