P4 Runtime: Putting the Control Plane in Charge of the Forwarding Plane. Presented by :

Transcription

1 P4 Runtime: Putting the Control Plane in Charge of the Forwarding Plane Presented by :

2 Today s Presenters Moderator Simon Stanley Analyst at Large Heavy Reading Nick McKeown Chief Scientist & Co-Founder Barefoot Networks Jim Wanderer Director of Engineering Google Timon Sloane VP Marketing & Ecosystem Open Networking Foundation

3 Agenda Introduction P4 Runtime - Nick McKeown (Barefoot Networks) An important P4 Runtime use case - Jim Wanderer, (Google) P4 Runtime integration with ONOS - Timon Sloane (ONF) Q&A

4 Network Virtualization and Open Solutions Network virtualization Based on SDN and NFV VNF Ecosystem Uses standard server hardware White box switches Control plane downloaded by operator Flexible solution Open solutions OpenFlow, OpenStack, OPNFV, Open vswitch (OVS) etc. ONOS (Open Network Operating System) Open source SDN network operating system for carrier-grade solutions Virtual Applications Network Services vswitch Server Hardware White Box Switches

5 Key Technology Developments Evolving switch chipset architectures Initially fixed function for performance Many configuration options have been added Several devices now have programmable packet processing P4 Packet Processing Language Developed by a group including Intel, Microsoft, Google, Barefoot, Princeton University and Stanford University Used to specify packet forwarding behaviour Open source consortium: P4.org Hardware agnostic switching and forwarding solution

6 Moving from OpenFlow to P4 Runtime OpenFlow OpenFlow Controller P4 Runtime Controller with P4 Runtime Agent OpenFlow Agent Abstraction Layer Linux OS Linux OS Software Stack P4 Runtime Agent S/S Switch Hardware Programmable Switch Hardware

7 P4 Runtime Putting the Control Plane in charge of the Forwarding Plane Nick McKeown Antonin Bas, Remy Chang

8 OSPF BGP VXLAN etc. Switch ASIC API Switch OS

9 OSPF BGP VXLAN etc. Switch ASIC API Closed, fixed and proprietary Switch OS

10 OSPF BGP VXLAN etc. Remote Control Plane OpenFlow ASIC A API Switch OS OpenFlow ASIC B API Switch OS OpenFlow ASIC C API Switch OS

11 OSPF BGP VXLAN etc. Remote Control Plane OpenFlow is open and silicon-independent, but fixed OpenFlow ASIC A API Switch OS OpenFlow ASIC B API Switch OS OpenFlow ASIC C API Switch OS

12 OSPF BGP VXLAN etc. SAI Switch ASIC API Switch OS

13 OSPF BGP VXLAN etc. SAI Switch ASIC API SAI is open and silicon-independent, but fixed Switch OS

14 Challenge Can we design an open, silicon-independent API that is easily enhanced as we evolve the forwarding plane? One that can be used equally for local or remote control planes. 14

15 Two things emerged 1. P4: An open language for describing how switches should process packets. 2. P4-programmable switch chips: e.g., the PISA architecture and Barefoot s Tofino switch chip. 15

16 Original P4 Paper Authors: P4.org Membership

17 PISA: Protocol Independent Switch Architecture Match+Action Stage Memory ALU Programmable Parser Programmable Match-Action Pipeline 17

18 Example P4 Program Parser Program parser parse_ethernet { extract(ethernet); return switch(ethernet.ethertype) { 0x8100 : parse_vlan_tag; 0x0800 : parse_ipv4; 0x8847 : parse_mpls; default: ingress; Header and Data Declarations header_type ethernet_t { header_type l2_metadata_t { header ethernet_t ethernet; header vlan_tag_t vlan_tag[2]; metadata l2_metadata_t l2_meta; Tables and Control Flow table port_table { control ingress { apply(port_table); if (l2_meta.vlan_tags == 0) { process_assign_vlan(); Memory ALU Programmable Parser Programmable Match-Action Pipeline 18

19 Barefoot Tofino 6.5Tb/s Switch The world s fastest switch. Behavior defined in P4. Programs always run at line-rate.

20 1 Protocol Authoring tor.p4 OSPF BGP VXLAN etc. API? Switch OS

21 1 Protocol Authoring 2 Compile 3 Configure tor.p4 OSPF BGP VXLAN etc. Auto-generated API Switch OS 4 Runtime!

22 Challenge Can we design an open, silicon-independent API that is easily enhanced as we evolve the forwarding plane? One that can be used equally for local or remote control planes. 22

23 1 Protocol Authoring tor.p4 OSPF BGP VXLAN etc. 2 Compile Remote Control Plane P4 Runtime Agent 3 Configure P4 Runtime Agent Switch OS

24 1 Protocol Authoring tor.p4 OSPF BGP VXLAN etc. 2 Compile Remote Control Plane P4 Runtime Agent P4 Runtime API 3 Configure P4 Runtime Agent Switch OS

25 1 Protocol Authoring tor.p4 OSPF BGP VXLAN etc. 2 Compile Remote Control Plane P4 Runtime Agent Open, silicon-independent, and extensible P4 Runtime API 3 Configure P4 Runtime Agent Switch OS Extended without restarting the Control Plane

26 In more detail 26

27 The P4 program tells us the API we need P4 Program (e.g. tor.p4) Runtime Table Update action set_nhop(bit<32> nhop) { table ipv4_lpm { key = { hdr.ipv4.dstaddr : lpm; actions = { drop; set_nhop; Table Update ipv4.dstaddr= /8 -> set_nhop( ) ipv4.dstaddr= /16 -> set_nhop( ) ipv4.dstaddr= /8 -> drop()

28 P4 Runtime extends API to include table P4 Program (e.g. tor.p4) action set_nhop(bit<32> nhop) { table ipv4_lpm { key = { hdr.ipv4.dstaddr : lpm; hdr.meta.vrf_id : exact; actions = { drop; set_nhop; Logical View of Entry ipv4.dstaddr= /8 -> drop() Protobuf Entry Encoding table_entry { table_id: match { field_id: 1 lpm { value: "\f\000\000\000" prefix_len: 8 match { field_id: 2 exact { value: "\000\000" action { action { action_id:

29 OSPF BGP VXLAN etc. Remote Control Plane P4 Runtime Agent table_entry { table_id: match { field_id: 1 lpm { value: "\f\000\000\000" prefix_len: 8 match { field_id: 2 exact { value: "\000\000" action { action { action_id: Protobuf format used by Control Plane to add/delete IPv4 entry P4 Runtime Agent Switch OS tor.p4

30 P4 Runtime for local Control Plane OSPF BGP VXLAN etc. P4 Runtime Switch OS Protobuf format used by Control Plane to add/delete IPv4 entry table_entry { table_id: match { field_id: 1 lpm { value: "\f\000\000\000" prefix_len: 8 match { field_id: 2 exact { value: "\000\000" action { action { action_id: tor.p4

31 Summary Existing APIs are either hidden behind NDAs, and/or they are hard to extend. Changing an existing API typically requires a lot of work, and a major interruption of service. The P4 Runtime API is easy to extend by nature: It is derived from the program that describes the forwarding behavior. The P4 Runtime API can be used equally well by a remote or local control plane. The Control Plane does not need to be interrupted when the API is changed. 31

32 Next Generation SDN Switch Future plans for Google s SDN Networks Jim Wanderer, Alireza Ghaffarkhah, Waqar Mohsin, Tom Everman, Lorenzo Vicisano, Babru Thatikunta, Amin Vahdat,...

33 (log scale) Bisection b/w (bps) 1000T 100T 10T 1T 0 4 Firehose Post Watchtower Firehose Saturn [Jupiter Rising ] Jupiter (1.3P) 1 3 Year

34 History For more details, see: Jupiter Rising: A Decade of Clos Topologies and Centralized Control in Google s Datacenter Network SIGCOMM 2015

35 (log scale) Bisection b/w (bps) 1000T 100T 10T 1T 0 4 Firehose Post Watchtower Spine Block Firehose 1.1 Aggregation Block Spine Block SDN Architecture Aggregation Block 0 9 Saturn Spine Block Centralized Control 1 2 [Jupiter Rising ] Jupiter (1.3P) 1 3 Year

36 OpenFlow Limitations Changed the way we built networks, but: Limited interface - scale, features Underdefined interface - match well defined, action ambiguous Behavior inconsistent over different switch types Result: Added special workarounds and extensions Specifications for specific behavior Customized OpenFlow 3rd party devices can t drop into the network fabric

37 New Hardware Whitebox / bare metal switches available: Accton Edgecore Delta Networks Quanta Cloud Technology OCP / Wedge Great fit for building DC fabrics Leverage new technology quickly Available now, fast time to deploy But, difficult to integrate

38 Integration / Support Large software effort: Platform specific system software e.g. drivers Proprietary switch vendor ASIC SDK Port Google Openflow extensions and workarounds Make Openflow function the same way on a new chip Standard routing protocols almost sound better? Interoperable Not tied to a particular HW platform

39 What is Needed for an SDN Switch Goals: Fast and easy use of best and newest hardware available High velocity to introduce new features Want: Easy to program Easy to configure Easy to manage Silicon and system independence / abstraction How?

40 Next Gen SDN Switch P4Runtime OpenConfig: gnmi gnoi Open Network Linux Platform P4 Runtime Agent Control P4 Runtime Management OpenConfig gnmi gnoi Open Network Linux Platform ASIC 1 ASIC 2 ASIC 3 ASIC 4

41 P4 Designed for programmable pipelines, but useful for fixed switches: Define expected switch behavior and capabilities Describe specific tables and functions L2 L3 ACL L3_LPM") table l3_ipv4_table { key = { hdr.ipv4_base.dst_addr : Bridge local_metadata.l3_selector_input: selector; actions = {...

42 P4 Runtime Protocol Configure the forwarding plane: Act on specific tables Read, Insert, Modify, Delete switch table entries Contract for a programming interface Openflow-like and well defined Forwarding State L3 L2 ACL ECMP Bridge

43 P4 Runtime Control P4 Runtime Protocol Agent Interface to switch ASIC Provides access to switch tables Transport: grpc, FB Swift, etc Replaces OpenFlow Agent Remote or Local Control ASIC pipeline can be: Fixed Programmable Hybrid Centralized Controller P4 Runtime P4 Runtime Agent Switch Stack SW SDK ASIC Switch

44 P4 Switch Abstraction Control Logical pipeline configured on switch Logical pipeline mapped to physical L3 Logical Program logical pipeline L2 ACL ECMP Mapping done via the P4 compiler and switch software. Bridge L3 ACL Physical iport ACL ACL L2 ECMP ACL Bridge ACL

45 P4 Runtime Multi-Vendor Control Logical Physical ASIC 1 ASIC 2

46 Configuration and Management OpenConfig Declarative configuration Streaming telemetry Model-driven management and operations gnmi - network management interface gnoi - network operations interface Vendor-neutral data models Address practical operational needs Management OpenConfig gnmi gnoi App SW Platform Software ASIC Hardware

47 System Software Hardware / Platform variations Open Network Linux Platform Abstraction layer to inventory, manage, and monitor platform devices Consistent API to platform level Fans, PSUs, LED, media, temperature, EPROMs, FPGAs, Management OpenConfig gnmi gnoi App SW ONLP ASIC Hardware

48 Vision Switch hardware system vendors provide: System software OpenConfig model support Chip vendors provide P4 Runtime for the ASIC P4 Compiler support for mapping logical pipelines to ASIC P4 Runtime + OpenConfig is the abstraction layer for switches Easy integration Fast deployment for best and latest hardware +

49 P4 Runtime Demo ONOS Controlling Barefoot Tofino Fabric

50 ONF A Track Record of Impact Operator Led Consortium

51 ONF A Track Record of Impact Operator Led Consortium Leading Open Source SDN Controller for Operators

52 ONF A Track Record of Impact Operator Led Consortium Nearly 40% of all end-customers will have service provided by CORD by mid-2021 Roz Roseboro Heavy Reading Leading Open Source SDN Controller for Operators *

53 P4 Runtime Enabling Data Plane Pipeline Independence Application OpenFlow Table Management Requires tweaks for variations in forwarding pipelines A COMPLEX PIPELINE Packets THAT DOES EVERYTHING...different vendors in their own way Fixed-function data plane pipeline

54 P4 Runtime Enabling Data Plane Pipeline Independence Application P4 Runtime enables interface to be generated from P4 program P4 program Table { match actions Application OpenFlow Table Management Requires tweaks for variations in forwarding pipelines Controller can work with a variety of data planes without modification compile P4 Runtime Agent grpc P4 Runtime Table Management Packets A COMPLEX PIPELINE THAT DOES EVERYTHING...different vendors in their own way Packets JUST I WHAT NEED Fixed-function data plane pipeline Programmable data plane pipeline

55 P4 Runtime Enabling Data Plane Pipeline Independence P4 program Application OpenFlow Table Management Requires tweaks for variations in forwarding pipelines P4 Runtime is of value even if the data plane is not programmable P4 can be used to unambiguously describe any pipeline 1 Table { match actions 2 compile Application P4 Runtime Agent grpc P4 Runtime Table Management Packets A COMPLEX PIPELINE THAT DOES EVERYTHING...different vendors in their own way Packets JUST I WHAT NEED Fixed-function data plane pipeline Programmable data plane pipeline

56 Live demo at SDN World Congress October 10-13, The Hague, Netherlands ONOS using P4 Runtime to: Manage a spine-leaf fabric Support data plane pipeline configuration Downloads P4 program via P4 Runtime Manipulate downloaded pipeline tables to manage traffic Via P4 Runtime protobuf definitions carried over grpc Google s tor.p4 used as P4 program Pipeline definition Demonstrated on three switch types 6.5Tb/s Barefoot Tofino based OCP Wedge 100BF Tb/s Barefoot Tofino based OCP Wedge 100BF-32 BMv2 Soft Switch

57 Looking Forward - Beyond the Demo Next Steps: Switch configuration via OpenConfig over gnmi Extend P4 Runtime support to other switch vendors/asics Support for new/existing ONOS applications with any P4 program Done via manual ONOS-to-P4 mapping Longer-Term Scope: Ability to understand P4 programs (automatic ONOS-to-P4 mapping) Rethink Northbound API to enable the full potential of P4 New Use Cases In-band Telemetry Spine-Leaf Fabric Optimization VNF Offloading

58 ONF Vision for leveraging a P4 Enabled Data Plane Virtualization is more than a VNF Monolithic VNFs Ports of legacy systems to x86 Failed to deliver the hoped for economics

59 ONF Vision for leveraging a P4 Enabled Data Plane Virtualization is more than a VNF Micro-Services Monolithic VNFs Ports of legacy systems to x86 Functions disaggregated and cloud agility achieved Failed to deliver the hoped for economics Economic crossover starts to be achieved

60 ONF Vision for leveraging a P4 Enabled Data Plane Virtualization is more than a VNF Monolithic VNFs Ports of legacy systems to x86 Failed to deliver the hoped for economics Micro-Services Functions disaggregated and cloud agility achieved Economic crossover starts to be achieved Micro-Services (x86) blended with P4 Enabled Flow-Services Portions of services are run in the data plane to achieve speed and scale 100x performance improvements possible pushing functionality into programmable data plane

61 Come Join the Community P4 Brigade within ONOS Project Wiki - P4.org P4 API Working Group: P4 Brigade Working Session, Sept 2017, Seoul, South Korea

62 Thank You

63 63 Summary Webscale and telecom operators are pushing for greater control of large networks Switch devices are becoming more programmable OpenFlow provides limited control of switching hardware through an open interface P4 is used to specify packet forwarding behaviour in some smart NICs and switch devices P4 Runtime provides a fully flexible and open interface between network controllers and switch dataplanes

64 Questions and Answers? Moderator Simon Stanley Analyst at Large Heavy Reading Nick McKeown Chief Scientist & Co-Founder Barefoot Networks Jim Wanderer Director of Engineering Google Timon Sloane VP Marketing & Ecosystem Open Networking Foundation

65 Thank you for attending! Upcoming Light Reading Webinars