Diff-serv motivations (contd)
#2. Diffserv is a considered to be crucial building block to provide performance assurances in IP-based VPNs.
- Other pieces: IPSEC (security & tunneling), L2TP (remote-access tunneling), and RSVP (QoS signaling)
#3. 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.
- Edge handles policy, contracting and billing.
- Interiors may participate in signaling