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Cs 552 Computer Networks Quality Of Service
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| bet | 5/12 | | Sana | 26.12.2023 | | Hajmi | 492 Kb. | | #128375 |
Bog'liq qos-f05 The Big Picture (2) RSVP terminology - Flow descriptor (Flow spec + Filter Spec)
- Flow spec (Rate, max burst)
- Sender can Explicitly specify flow spec or not specify
- Filter Spec (Sender address, TCP/UDP, Port#)
- Aids in combining similar flows
- Filter can be shared (SE-style) or can use wild cards (all senders on a given port or a given sender on all ports, etc)
- The style may be shared or distinct in a sense that all reservations may be handled as one single reservation or there may be a single reservation for each upstream sender respectively.
RSVP Basic Operations - Sender: sends PATH message via the data delivery path
- Receiver sends RESV message on the reverse path
- Things to notice
- Receiver initiated reservation
- Decouple routing from reservation
- Two types of state: path and reservation
RSVP messages - PATH message – sets up state along path followed by packets
- RESV message – request for reservation back along setup path path
- PATH_TEAR, RESV_TEAR, RESV_CONFIRM, RESV_ERROR, PATH_ERROR
RSVP PATH MESSAGE - From sender to receiver (unicast or multicast)
- Intercepted at each RSVP aware hop
- Includes
- Sender TSpec : Traffic characteristics of the sender
- Token bucket rate, depth, max flow rate, max packet size
- forms one side of the ``contract'' between the data flow and the service.
- F-flag: specify whether filtered reservation is allowed
- Routers store:
- Path state, i.e., PHOP address to previous hop (RSVP aware node)
- If F-flag is set, store sender and its flowspec
- Otherwise, just add new link to multicast tree
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