SIMPLE Problem Statement

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

2. 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 IETF 66 – SIMPLE WG

3. 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 IETF 66 – SIMPLE WG

4. 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 IETF 66 – SIMPLE WG

5. 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 IETF 66 – SIMPLE WG

6. 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 IETF 66 – SIMPLE WG

7. Numbers Subscription lifetime = 8 hours, subscription refresh interval – 1 hour Numbers are between two domains only… IETF 66 – SIMPLE WG

8. 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 IETF 66 – SIMPLE WG

9. 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 IETF 66 – SIMPLE WG

10. Next Steps? IETF 66 – SIMPLE WG