Integrated Services (IntServ) provides guaranteed QoS through per-flow reservations. Each flow requests bandwidth, and routers reserve resources.
RSVP (Resource Reservation Protocol):
- Sender sends PATH message describing traffic
- Receiver sends RESV requesting reservation
- Each router reserves bandwidth
- Soft state requires refresh messages
IntServ problems:
- State explosion. Routers track every flow.
- Core router burden. Millions of flows impossible.
- Signaling overhead. RSVP consumes resources.
IntServ works for small networks. It does not scale to large backbones. Time complexity is for flows on each router.