QoS/CoS interest

     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,
     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.
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