1. IETF 66 – SIMPLE WG SIMPLE Problem Statement Draft-rang-simple-problem-statement-00 Tim Rang - Microsoft Avshalom Houri – IBM Edwin Aoki – AOL

2. IETF 66 – SIMPLE WG Motivation Deployment experience of SIMPLE based systems shows scalability issues with respect to number of messages Number of messages in several typical deployments is calculated and shown to be very high (even with optimizations) Suggesting that further work in SIMPLE WG is needed in order to have more and better optimizations

3. IETF 66 – SIMPLE WG Optimizations Considered Two categories of optimizations were considered: –Dialog saving optimization i.e. event-list or uri- list that enable using a single subscribe dialog for many subscriptions –Notification optimizations i.e. subnot-etags by Aki Niemi which suppresses non necessary notifies

4. IETF 66 – SIMPLE WG Computation Described in detail in the draft Input parameters –Subscription lifetime –Presence state change/hour –Subscription refresh interval/hour –Total federated presentities per watcher –Number of dialogs per watcher (optimization dependent) –Number of watchers in each domain

5. IETF 66 – SIMPLE WG Widely Distributed Inter-Domain Users of each domain are not usually subscribed to presence within the domain For example small public servers Numbers used –Subscription lifetime – 8 hours –Presence state changes per hour – 3 –Subscription is refreshed every hour –Total watched presentities – 20 –Number of watchers in each domain – 20,000 –Number of dialogs per watcher - 20 (non optimized), 1 (optimized) Not Optimized –Total of messages (8 hours) between domains – 70.4M –Number of messages per second - 2,444 Optimized –Total of messages (8 hours) between domains – 39.36M –Number of messages per second - 1367

6. IETF 66 – SIMPLE WG Other models Simple case – two domains connecting Associated inter domain – e.g. enterprise servers. Assuming it is the same as widely distributed inter-domain with respect to traffic between domains Very large network peering – e.g. consumer IM networks Intra domain peering – e.g. multiple presence servers in the same domain

7. IETF 66 – SIMPLE WG Numbers msgs/sec – non optimized / optimized Total msgs – non optimized / optimized # of watchers between domains Presentities per watcher Presence change/hour Model 489 / 30014.08M / 8.64M20,00043Common case 2,444 / 136770.4M / 39.36M20,000203Widely dist. inter-domain / Associated inter-domain 944K / 683K27.2B / 19.68B10M106Very large network peering 3,667 / 2,100105.6M / 60.48M60,000103Intra-domain Subscription lifetime = 8 hours, subscription refresh interval – 1 hour Numbers are between two domains only…

8. IETF 66 – SIMPLE WG Summary The numbers presented are only between two domains, when more domains are connected the number of messages will be multiplied Although current optimizations can reduce the traffic by up to 50%, the traffic is still very high Conservative numbers were used, in real life numbers may be even higher

9. IETF 66 – SIMPLE WG Conclusions Seems that further work in SIMPLE WG is needed in order to have better optimizations Initial set of requirements is included in the draft. Examples: –It is highly desirable for inter-domain network to scale linearly as number of watchers and presentities increase linearly –The solution SHOULD NOT require significantly more state in order to implement the solution –It MUST be able to scale to tens of millions of concurrent users in each peer domain –It MUST support a very high level of watcher/presentity intersections in various intersection models –Protocol changes MUST NOT prohibit optimizations in different deployment models esp. where there is a high level of cross subscriptions between the domains

10. IETF 66 – SIMPLE WG Next Steps?