1 SASP v1 (Server/Application State Protocol) draft-bivens-sasp-00.txt Alan Bivens IBM Research New York, USA IETF 60

2 SASP objectives Provide a mechanism for workload managers to give distribution recommendations to load balancers. Must be lightweight –little implementation complexity –little processing overhead –little additional user configuration Must be free of corporate ownership issues Must be extendible Control must remain at the load balancer SASP will not handle the transport or actual distribution of work, only give recommendations

3 Example System Architecture Group Workload Manager Individual Workload Manager Member Requests Load Balancer Request Origins Individual Workload Manager Member Individual Workload Manager Member Requests SASP Protocol Characteristics Binary Streams SSL

4 SASP Messages Registration Messages DeRegistration Messages Get Weight and Send Weight Messages Set Member State Messages Set LB State Messages

5 Example Flow A: (lb registration, get weights, and resource set state) 1.LB registers A, B, and C in GRP1. GWM replies with no error. 2.LB sends Get Weights message for GRP1 and receives the following: 3.LB sends Set LB State Message: 4.A sends SetMember State Message: 5.Resource C sends a Set Member State message to quiesce itself with the following flags: Load Balancer Member C Member A Member C Group Workload Manager time Register A, B, C in group GRP1 Register Reply Get Weights for GRP1 Get Weights Reply Get Weights for GRP1 Get Weights Reply 4 Set State for ResourceA Set State Reply Set Quiesce State ResC Set State Reply Get Weights for GRP1 Get Weights Reply Set Quiesce State ResC GroupMemberOpaque State General Flags Weight GRP1 Resource A0x Resource B0x Resource C0x MemberOpaque StateFlags Resource A0x MemberOpaque StateFlags Resource C0x0A Set State for LB Set State Reply MemberLB HealthFlags Load Balancer0x7F

6 Example Flow A (continued) : (lb registration, get weights, and resource set state) 6.LB sends the Get Weights message for GRP1 and receives the following: 7.Resource C sends a Set State message to un-quiesce itself with the following flags: 8.LB sends the Get Weights message for GRP1 and receives the following: Load Balancer Member C Member A Member C Group Workload Manager time Register A, B, C in group GRP1 Register Reply Get Weights for GRP1 Get Weights Reply Get Weights for GRP1 Get Weights Reply 4 Set State for ResourceA Set State Reply Set Quiesce State ResC Set State Reply Get Weights for GRP1 Get Weights Reply Set Quiesce State ResC GroupMemberOpaque State General Flags Weight GRP1 Resource A0x Resource B0x Resource C0x0A11110 MemberOpaque StateFlags Resource C0x0A0000 GroupMemberOpaque State General Flags Weight GRP1 Resource A0x Resource B0x Resource C0x0A Set State for LB Set State Reply

7 Only Overlap between SASP and RSERPOOL Providing “A means for allowing flexible load assignment and balancing policies” –SASP provides a manner of doing this between two entities, but not by way of a policy.

8 Differences between SASP and RSERPOOL Terminology and topology: –PU -> client, outside of SASP scope –PE -> group member –ENRP Server -> some blend of load balancer and GWM Traditional load balancing does not have such an entity –PU Proxy -> outside of SASP scope, not needed for traditional load balancing

9 Differences cont. Flow of protocols: –ASAP/ENRP: PE registers with the ENRP Server PU contacts ENRP server for PE handle resolution, and then contacts PE using designated transport protocol –SASP/Traditional load balancing: Load balancer admin registers all group members. Load balancer is transparent, client contacts load balancer using expected transport protocol and receives reply from initial message

10 Current State of SASP Multiple vendors have begun to announce support of this protocol 2 implementations of SASP GWM components coming out in products this year. 2 interoperating implementations of SASP Router component by two different vendors this year. Current version of SASP available as individual ID “

11 What next Should this be an informational RFC? Would this working group like to adopt it as a standards track document? Should we have a full BOF at the next IETF?

12 Thank You

13 Extra Slides Basic Protocol Components Group Protocol Components Message Types

14 Basic Protocol Components Member State Instance Group Data Protocol Port IP Address Label length Label Member Data Opaque Member State Field Weight Contact Flag Quiesce Flag Registration Flag Confident Flag SASP Header Member Data Weight Entry Version Message Length Message ID 5 Basic Components are used throughout the protocol Member Data Opaque State Quiesce Flag LB UID Length LB UID Group Name Length Group Name

15 Group Protocol Components Group of Weight Data Group of Member State Data Group Data Member Data Count Array of Member Data Components Group Data Weight Entry Count Array of Weight Entry Components Group of Member Data 3 Group Components are used throughout the protocol Group Data Resource State Instance Count Array of Resource State Instances

16 Registration Messages Registration Deregistration Group Workload Manager Load Balancer SASP LB || Member ---> GWM (Request)(Response) SASP Header “Group of Member Data” Count Array of “Group of Member Data” Components SASP Header Return Code LB || Member ---> GWM (Request)(Response) SASP Header “Group of Member Data” Count Array of “Group of Member Data” Components Reason SASP Header Return Code Individual Workload Manager Resource

17 Weight Exchange Messages Get Weights Send Weights Group Workload Manager Load Balancer SASP LB ---> GWM (Request)(Response) SASP Header Group Data Count Array of Group Data Components SASP Header Group Weight Data Count Array of Group Weight Data Components Return Code Interval GWM ---> LB (Push)No Response SASP Header “Group of Weight Data” Count Array of “Group of Weight Data” Components Fields in Weight Entry Weight Entry fields Opaque Member State Contact Flag Quiesce Flag Registration Flag Confident Flag Weight

18 Set Member State Messages Set Member State Group Workload Manager Load Balancer SASP Individual Workload Manager Resource LB || Member ---> GWM (Request) (Response) SASP Header LB or Member Flag “Group of Member State” Count Array of “Group of Member State” Components SASP Header Return Code Fields in Member State Instance Member State Instance fields Opaque State Quiesce Flag SASP

19 Set Load Balancer State Messages Group Workload Manager Load Balancer SASP LB ---> GWM (Request)(Response) SASP Header LB Identifier Length LB Identifier Push Flag Trust Flag No Change / No Send Flag LB Health SASP Header Return Code Set Load Balancer State