[e2e] Types Of Service
braden at ISI.EDU
Thu Jul 31 15:24:06 PDT 2003
*> > *> However, only TCP, UDP, and RTP (which is built over UDP) come to my
*> > mind,
*> > *> they don't guarantee any specific type of service (for example, "low
*> > *> delay", "high throughput", etc.) by themselves.
*> > *>
*> >But in principle, they could. The original IP specification DID
*> >include a TOS byte with delay and throughput bits.
*> Yes, but it didn't *guarantee* the service.
By and large, guarantees are for lawyers. It is not clear that users
really care about guarantees that much. They just want it to
work well enough.
*> > *> Besides that, for example, TCP provides a "realiable" byte stream.
*> > However,
*> > *> there are some errors that TCP won't catch, so if reliability is a real
*> > *> issue, then another layer of error control must be built up on top
*> > of TCP.
*> > *>
*> >Presumably you are referring to local system errors between TCP and the
*> >applications. This would ultimately have to be dealt with at the
*> >application layer, of course (see the classic E2E argument paper.)
*> What's the author/title of that paper? Is it available online?
Saltzer, J., Reed, D., and D. Clark, End-To-End Arguments in System Design. ACM Transactions on
Computer Systems 2, 4 (November 1984) pp. 277-288. An earlier version appeared in the Second International
Conference on Distributed Computing Systems (Paris, April 1981) pp. 509-512
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