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High-Performance Routing (HPR)

High-Performance Routing (HPR). 1129_04F8_c2. Dave McCowan. Software Engineer dmccowan@cisco.com. Agenda. Why Enterprises Are Using APPN IBM Networking Models Role/Benefits of APPN in Each Model Customer Updates—ISR to HPR Summary. What Is HPR?. Architectural enhancements to APPN that

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High-Performance Routing (HPR)

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  1. High-Performance Routing (HPR) 1129_04F8_c2

  2. Dave McCowan Software Engineerdmccowan@cisco.com

  3. Agenda • Why Enterprises Are Using APPN • IBM Networking Models • Role/Benefits of APPN in Each Model • Customer Updates—ISR to HPR • Summary

  4. What Is HPR? • Architectural enhancements to APPN that • Improve performance • Faster intermediate node routing • Improve reliability • Nondisruptive session switch • While providing • Functional equivalence to APPN • Interoperability with existing APPN nodes

  5. What Can HPR Do for My Network? • Better availability • No outages for planned or unplanned network orintermediate node outages • Better intermediate node performance • Performance improved, reduced storage requirements, reduced processing requirements • Better congestion control • End-to-end congestion control, adapts to fully utilize links, rate-based algorithm • Full class of service support • Prioritization of data, controlled data path selection • Selective end-to-end retransmission

  6. HPR Highlights • Establishes a transport pipe • Uses CoS for route calculation • Runs on existing hardware • Transports data at high speeds • Reroutes nondisruptively RTP Pipe SNA Sessions RTP End User

  7. HPR Components • Data-link control • Standard DLCs • E.g. Frame Relay, LAN • Automatic Network Routing (ANR) • No session awareness • Improves routing speed • Traffic prioritization • Rapid Transport Protocol (RTP) • End-to-end error recovery • Selective retransmission • Nondescriptive rerouting • Adaptive rate base flow control RTP Pipe Data Link RTP End User ANR Router

  8. APPN Routing: ISR Vs. HPR • ISR: • Transmission priority • Forward packet • Flow control • Segmentation • Error recovery • LFSID label swap • RTP: • Congestion control • Segmentation • Error recovery • ANR: • Transmission priority • Forward packet

  9. HPR Data Link Controls • Local-area networks • Token Ring, Ethernet, FDDI • Wide-area networks • Frame Relay, PPP, SMDS, QLLC, SDLC • RSRB, DLSw+ • ATM • RFC 1483, LAN Emulation • Channel

  10. ANR Transport Characteristics • Connection • In-order delivery • Same route • Route setup • Reservation • Low overhead addressing • Corrects errors • Congestion control • Connectionless • Out-of-order delivery • Different routes • No route setup • No reservation • High overhead addressing • No error correction • No congestion control 1129_04F8_c2 9

  11. RTP Tower • Rapid Transport Protocol (RTP) • Connections that carry session traffic • Protocols executed at “edge” of HPR network • Multiplexed sessions with same CoS • Nondisruptive path switch for failed RTP connection • APPN/HPR boundary function

  12. HPR Boundary Function CS/2 NN D NN F 4 1 NN G 3 7 2 NN H 8 NN A NN B VTAM 4.3 6 5 NN C NN E • “Translates” ISR traffic to/from HPR traffic • Seamless migration from ISR to HPR • Continued support for current APPN features • Transmission priority, DLUS/DLUR, connection network, network management, end node • HPR features only active inside HPR subnet 1129_04F8_c2 11

  13. HPR Packet Types Between HPR Nodes Three Types of Packets May Flow: XID3 Packet XID3 I-Frame FID2 PIU Packet FID2 TH RH RU Network Layer Packet (NLP) NHDR THDR DATA

  14. HPR XID3 Packets XID3 Packet XID3 I-Frame X’61’ HPR Capabilities Vector (CV61) • Presence indicates sender HPR capable • Error recovery mode • Tower support indicators • ANR label information (NCE ID)

  15. HPR FID2 PIU Packet FID2 PIU Packet FID2 TH RH RU • First four bits of TH X’0010’ • SSCP-PU, SSCP-LU, and LU-LU sessions for dependent LUs • CP-CP session • Route setup messages

  16. Route Setup Request FID2 TH RH RU X’10’ Route Setup Request GDS X’12CE’ X’12CE’ Dest Info Control Vectors RSCV (X’2B’) FQPCID (X’60’) CoS/TP (X’2C) Forward Route Information (X’80’)

  17. HPR Network Layer Packet (NLP) Network Layer Packet (NLP) NHDR THDR DATA • First four bits of header x’110x’ • Network layer header (NHDR)—ANR routing information • RTP transport header (THDR)—RTP information • Data portion includes new FID5 PIU for independent LU-LU sessions • Packets flow interleaved with FID2 packets

  18. Network Layer Header (NHDR) NHDR THDR DATA B’1100’ TP … ANR Routing Field X’FF’ • ANR routing field contains consecutive labels for each TG in the session path • Labels 1–8 bytes • Assigned in “outbound direction”—unique to assigning node • Labels removed from ANR field as used • Last label a Network Connection Endpoint (NCE) • Identifies component receiving message in final node

  19. Network Connection Endpoint (NCE) • Last label in ANR routing field • Identifies what component receives message • Three types of components identified • CP NCEs—exchanged with XID3 • LU NCEs—returned on LOCATE • Boundary function NCE—carried on route setup • Route setup NCE—exchanged with XID3

  20. ANR Routing Example 96 75 64 NCE: 80 NCE: 80 81 92 73 NN C NN D NN E NN F ANR (92, 73, 80) ANR (73, 80) ANR (80) ANR (80) ANR (96, 80) ANR (75, 96, 80)

  21. LU-LU Session Setup Summary NN D NN F CS/2 4 1 NN G 7 3 2 NN H 8 VTAM 4.3 NN B NN A NN C NN A NN B NN C NN D NN F NN G NN H BIND Route Setup (REQ) Route Setup (REQ) Route Setup (Reply) Route Setup (Reply) RTP Connection Setup + BIND BIND + BIND Rsp RTP Connection Setup Reply + BIND Rsp + BIND Rsp

  22. Route Setup—Detail 83 84 TG1 TG2 86 95 NN C NN D NN E Route Setup (REQ) Route Setup (REQ) Route Setup Request Destination Hop Index (2) RSCV (Current Hop (1) TG1 to NND TG2 to NNE) CoS/TPF FQPCID Forward ANR (83) Route Setup Request Destination Hop Index (2) RSCV (Current Hop (2) TG1 to NND TG2 to NNE) CoS/TPF FQPCID Forward ANR (83, 84)

  23. NN C NN D NN E Route Setup—Detail (Cont.) NCE:77 NCE:99 83 84 TG1 TG2 86 95 Route Setup (Reply) Route Setup (Reply) Route Setup Reply Destination Hop Index (2) CoS/TPF FQPCID Forward ANR (83, 84, 99) Reverse ANR (95) Reverse RSCV (NNE to TG2 to NND) Route Setup Reply Destination Hop Index (2) CoS/TPF FQPCID Forward ANR (83, 84, 99) Reverse ANR (95, 86) Reverse RSCV (NNE to TG2 to NND to TG1 to NNC))

  24. RTP Connection Setup NCE:77 NCE:99 83 84 TG1 TG2 86 95 NN C NN D NN E RTP Connection Setup Connection Setup Reverse ANR (95, 86, 77) Reverse RSCV (NNE-TG2-NND-TG1-NNC) FID5 Header (Session Address) BIND Connection Setup Reverse ANR (95, 86, 77) Reverse RSCV (NNE-TG2-NND-TG1-NNC) FID5 Header (Session Address) BIND RTP Connection Setup Reply (Including + Response to BIND) 1129_04F8_c2 23

  25. NN C NN D NN E Existing RTP Connection NCE:77 NCE:99 83 84 TG1 TG2 86 95 Existing RTP Connection BIND + BIND Rsp

  26. Reliable RTP Transport • THDR contains retry indicator • Sender will retransmit packets lost • THDR contains status requested indicator • Requests acknowledgment of data successfully received • Status segment from receiver identifies packets received • Sender releases buffers when received

  27. Status Example NN F NN D NN C NN C NN D NN F MSG 1, Status Req Status—Got MSG 1 MSG 2, No Status Req MSG 3, No Status Req MSG 4, Status Req Status—Got MSG 3, 4 MSG 2, Status Req Status—Got MSG 2

  28. Byte Sequence Numbers RTP A RTP B THDR (SOM, EOM, BSN (1), Data (ABC) (3 Bytes Data+1 Byte EOM) THDR (SOM, EOM, BSN (5), Data (DE) (2 Bytes Data+1 Byte EOM) THDR (SOM, No EOM, BSN (8), Data(F) (1 Byte Data+0 Byte EOM) THDR (No SOM, No EOM, BSN (9), Data (G) (1 Byte Data+0 Byte EOM) THDR (No SOM, EOM, BSN (10), Data (H) (1 Byte Data+1 Byte EOM) THDR (SOM, EOM, BSN (12), Data (Null) (0 Bytes Data+1 Byte EOM) THDR (SOM, EOM, BSN (13), Data (IJK) (3 Bytes Data+1 Byte EOM) What Is the Next BSN? 17

  29. Requesting Retransmission RTP A RTP B • Gap in BSN indicates a message lost • Status message to sender asks for retransmission of one message THDR (SOM, EOM, BSN (1), Data (ABC) 1 + 1 (EOM) + 3 (Data) = 5 THDR (SOM, EOM, BSN (5), Data (DE) 5 + 1 (EOM) + 2 (Data) = 8 THDR (No SOM, No EOM, BSN (9) , Data (G) Oops! X’0E’, GAPDETR, Received BSN, ABSP

  30. HPR Segmentation • Message segmentation and reassembly only at end RTP nodes • NLP message size cannot exceed smallest link BTU size along session path • Includes NHDR, THDR, and data • Route setup sequence carries maximum packet size field • X’80 route information CV on route setup GDS variable X’12CE” • Node replace is maximum packet size on next hop less than what’s in the field • Minimum acceptable packet size 768 • NHDR and THDR cannot be segmented

  31. Segmentation and Reassembly CS/2 NN D NN F 1 4 NN G 3 7 2 NN H 8 NN A NN B VTAM 4.3 NN C NN A NN B NN C NN D NN F NN G NN H PIU (Segments 1-j) NHDR, THDR (SOM), DATA (PIU (Part 1) NHDR, THDR, DATA (PIU (Part 2) • • • NHDR, THDR (EOM), DATA (PIU (Part k) PIU (Segments 1-m)

  32. Flow/Congestion Control • Adaptive rate-based flow control • Provide fairness between RTP connections • Session pacing • Provide fairness between sessions within an RTP connection

  33. ARB Flow/Congestion Control Knee = Point Where Congestion Starts Cliff = Congestion Results in Packet Loss and Queuing Delays ARB Keeps Traffic in the Operating Region Operating Region Knee Cliff Throughput Send Rate • Input traffic reduced as network approaches congestion • Input traffic increased when network capacity increases

  34. Properties of ARB • Adapts to network conditions to maximize throughput and minimize congestion • Smooths input traffic to avoid bursts • Provides end-to-end flow control so one endpoint cannot flood the other • Requires minimal processor cycles and network bandwidth • Provides fairness to all RTP connections

  35. How ARB Works Intermediate Node RTP RTP Rate Req and Data ARB Sender ARB Receiver Rate Reply Rate Req and Data ARB Receiver ARB Sender • Closed-loop mechanism based on information exchanged between 2 RTP endpoints • ARB setup on RTP connection setup or path switch Rate Reply

  36. The ARB Algorithm Interval 1 Interval 2 Interval 3 Receiver Time Reply Reply Reply REQ REQ REQ Sender Time Interval 1 Interval 2 Interval 3 • Sender sends interval since last request • Receiver measures interval since last request • Receiver recommends action sender should take

  37. ARB Features • Burst timer indicates when the ARB sender may send a “burst size” of data • A rate request and rate reply may be in the same message • Recommendations to sender: • Normal—increase send rate • Restraint—no rate change • Slowdown1—reduce rate (~12.5%) • Slowdown2—reduce rate (~25%) • Critical—reduce rate (~50%)

  38. Traffic Prioritization • Same CoS/transmission priority as base APPN • Intermediate node processes transmission priority • RTP connections with same CoS/transmission priority sharing a link get equal share of bandwidth • Fairness occurs because incrementing and decrementing done consistently across connections

  39. The Switch CS/2 NN D NN F 4 X 1 NN G 3 7 2 NN H 8 NN A NN B VTAM 4.3 6 5 NN C NN E • Automatically reroute RTP connection traffic around a failed link or node • Only operates within an HPR subnet • Alternate path must be HPR-only and support the same CoS

  40. Switch Triggers • RTP connection failure detection • Status requested message sent—timer expires • Retry limit exceeded • Operator request • Used to switch back if original path optimal

  41. Path Switch Sequence CS/2 NN D NN F 4 1 NN G 7 2 NN H 3 8 NN A NN B VTAM 4.3 6 5 NN C NN E NN D NN C NN E NN F TDU Update Calculate RSCV Route Setup Req Route Setup Req Route Setup Reply Route Setup Reply Data • • •

  42. Cisco High-Performance Routing • Evolutionary extension to APPN • Better performance, lower overhead • Higher-link utilization, predictable response time • Complements networking trends • Supports class of service and transmission priority • Drop-in migration for current APPN networks

  43. Positioning APPN in a Multiprotocol Network

  44. Why Use APPN/HPR? • Data center and FEP backbone • Support for high-availability sysplex environment • Native SNA routing • Reduced FEP dependency • Simplified configuration • Branch • Peer-to-peer communications • End-to-end class of service

  45. APPN—What Our Customers Tell Us Reason 1997 1998 Native SNA Routing 90% 100% Reduced FEP Dependency 80% 90% Support For Sysplex 70% 70% Simplified Configuration 50% 50% Peer-to-Peer Communication 20% 10% VTAM Currency NA 10% 1129_04F8_c2 44

  46. Why Use HPR? • Required for Sysplex environment • Improved intermediate node throughput • Improved availability—routing around failed nodes

  47. HPR—What Our Customers Tell Us Reason 1998 Data Center/Network Availability 90% Sysplex 70% Improved Performance 10% End-to-End Availability 10%

  48. APPN in a Parallel Sysplex ICN1/DLUS MDH1 MDH2 ICN2/DLUS (Backup) ESCON Director Coupling Facility APPN • Generic resources • Multihost persistent sessions (requires HPR) NN/DLUR NN/DLUR

  49. HPR—High Availability Options RTP RTP CMPC CSNA ANR SRB … … ANR Switching SR Bridging RTP or ANR/ DLUR Routers DLSw+ (Optional RTP) DLSw+ or RFC1490 Routers

  50. HPR—Option Comparison ANR Node XCA Node Function Performedby Channel-Attached Router ANR Switch Source Route Bridge (“Duplicate TICs”) Who Uses the Solution? New APPN Installations Migration from Existing ISR Installation Performance 100,000 PPSFast Switched 100,000 PPS Fast Switched Points of Failure Application, End User Application, End User 1129_04F8_c2 49

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