Paul, Even if QoS/CoS is desirable, is its widescale deployment possible given the current Internet? Here are some of the issues stopping QoS: 1. No billing available: If there is no billing system which can determine when people use QoS capabilities, than how can it be deployed widely and effectively. 2. No support on routing infrastructure: Routers today have several problems: * No policing at ingress: You can't have QoS unless you can limit how much traffic enters the network, and discard, or at least mark the excess traffic. * No effective BW reservation mechanism: RSVP may solve this in the future, but it's not deployed now. * No effective Class of Service mechanism: * Packet/sec processing limits: Even if the Internet infrastructure knows how to do all of the above, (reserve, police, mark, and queue according to QoS parameters), it will still fail if the box cannot satisfy the packet rates coming to it. Both your company and mine are working on ways to fix these limitations. But widescale QoS capabilities requires that every router between a source and destination has these capabilities. QoS guarantees maybe possible within a single AS that uses a router infrastructure with Frame Relay or ATM switching capabilities (which tend to have implicit support for all of the above listed features). Of course, this leads to the next problem, namely: 3. No support across ASes. First of all, BGP provides no QoS metrics. So there is no way to determine if a particular AS should even be considered in setting up a QoS path. Second, while a single AS could be upgraded to QoS-capable equipment, a forklift upgrade across the Internet to QoS-capable equipment won't happen anytime soon. I think the Internet will stay at best-effort for quite a while, with small pockets of QoS in special situations. Prabhu ______________________________ Reply Separator _________________________________ Subject: QoS/CoS interest Author: Paul Ferguson <pferguso@cisco.com> at SMTPLINK Date: 5/21/97 3:04 PM I'd like to get a feel for what the temperature level is in the ISP community for this issue -- I have a vested [personal] interest in understanding what your understanding & implementation plans are in this arena. Please send your thoughts, requirements, bitches, etc., to me personally, or preferably, to the NANOG list; it is a greater audience than myself that wishes to understand these issues. Thanks! - paul