Diff-serv motivations
#1. Economics of ISPs (access and transit providers) dictates need for service differentiation
- IP provides just a best effort service
- ISPs, not IETF, should to define services (unlike int-serv).
- These services could be qualitative instead of the largely quantitative services attempted by IETF.
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#2. Int-serv/RSVP does not scale
- Diff-serv uses a limited set of “behavior aggregates (BA)”
- Diffserv creates a separation between edge and core routers.
- Move per-flow (possibly non-scalable) data path functions (or MF-classification) to edges.