Why RSVP/Diffserv? RSVP scalability concerns are impeding broad scale deployment Diffserv is scaleable but no inherent support for quantitative QoS Expect applications and hosts which are ready to signal for tighter, per-flow QoS (Quantitative QoS applications) –IP telephony, Video-on-demand, Non-multimedia Complementary technologies
Sender Receiver DS Provider CN 1 CN 2 Service Agreement: PHB A; token bucket = TB2 PHB B; token bucket = TB1 1. Sender sends RSVP PATH towards Receiver. 2. Standard RSVP processing is applied within CN1. 3. RSVP policy check is applied before ingress to DS provider network. Policy check is approved. 4. PATH message is tunneled through the DS provider network transparently.. 5. Standard RSVP processing is applied within CN2. 6. Receiver responds with RSVP RESV message. RSVP Policy Server and policy database
7. Standard RSVP processing is applied within CN2. RESV is admitted. 8. RESV is tunnelled through DS network transparently. 9. RESV arrives at edge router. Edge router sees that the RESV wishes to reserve resources (TB2’) for the intserv service that maps to PHB A. Since TB2 > TB2’, ingress router approves RESV by allowing it to pass on upstream. 10. In CN1, standard RSVP processing is applied (may include additional policy check). 11. When RESV arrives at sender, sender begins marking traffic on corresponding flow for PHB A. Sender Receiver DS Provider CN 1 CN 2 RSVP Policy Server and policy database Service Agreement: PHB A; token bucket = TB2 PHB B; token bucket = TB1
Work in Diffserv and RSVP/Intserv Define diffserv PHBs which extend intserv service types (similar to intserv/802.1p) –Standardize PHB set –Add object to RSVP messages to aid mapping Define boundary device functionality –represent diffserv admission control using RSVP Transparently carry RSVP messages through diffserv network
Codepoint Overlap Recommend separate codepoints for qualitative vs. quantitative services –prevent uncontrolled (qualitative) traffic from ‘stealing’ resources from controlled ‘quantitative’ traffic –ocasionally, overlap may be inevitable use MF classification to separate sources of traffic –relative ordering of codepoints?
More than one CL? Might distinguish between latency tolerant controlled load and latency-intolerant controlled load –recommend binary distinction (vs. continuous) –e.g. a/v application generates two traffic streams: audio - latency intolerant video - latency tolerant
Mapping Mechanisms Default mapping Ability for network to indicate alternate mapping to hosts –use RSVP signaling extensions –if no signaling, use default –avoid host configuration
New RSVP Objects DS Object –network signaling to sending host –specifies DS codepoint which should be used to extend Intserv service type requested –returned to sender in RESV message –inserted in send direction or receive direction? Latency tolerance indicator –extend sender Tspec object?
RSVP Transparency to Diffserv Diffserv core routers shouldn’t see RSVP –RA option field to indicate that core routers should ignore RA (per Aggregating RSVP Based QoS Requests) –Ingress routers turn off RA for protocol 46, egress routers turn it back on if RA is used for other than RSVP, this causes problems –Core routers ignore RA if protocol 46
Diffserv Transparency to RSVP Don’t want break bit set in diffserv cloud –if RSVP messages are transparent in diffserv cloud, perhaps this ‘just works’ –otherwise, diffserv routers must cancel break bit on egress
Network Control Priority for RSVP Messages In congested 802 LANs, RSVP messages may get lost –assign them 802.1p NC priority –police
Action Items Mapping draft –specify modifications to RSVP messages if necessary Diffedge draft –Determine mechanism to be used for hiding RSVP messages in core effect of break bit? –Formalize configuration protocols, table formats in diffedge Miscellaneous –Network control priority for RSVP?
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