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Transcript of HUAWEI TECHNOLOGIES CO., LTD. Protocol Oblivious Forwarding: Unleash the Power of SDN through a...
HUAWEI TECHNOLOGIES CO., LTD.
www.huawei.com
Protocol Oblivious Forwarding: Unleash the Power of SDN through a Future-Proof Forwarding Plane
Haoyu SongNetworks Business Unit, Technology Strategy, IP ResearchHuawei Technologies, USA
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 2
What Happened to Your Mobile Phone: A Metaphor
Preloaded with all the features Get new models for new apps No way to customize
Download only the apps you need New features in new software release Write your own apps
Decoupling the platform and the apps is the key for smart phone’s success. The real value exists in services provided by software. Better hardware can carry and deliver the value better.
Past Now
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 3
Network Device Programming Models
Control Plane
Data Plane
“Black Box”
Closed and proprietary design that meets the pre-defined service requirements
Device Vendor-driven Programmability
Man
ag
emen
t
I can only use the device as- is.
Device Vendor/Service Provider Split Programmability
Control Plane
Data Plane
OpenFlow 1.x
“Gray Box”
Open interface using existing technology building blocks for limited programmability
Co
ntro
l
I can do what the device has supported.
Service Provider-driven Programmability
Control Plane
Data Plane
Open interface using generic network programming model, enabling full programmability
“White Box”
Pro
gram
OpenFlow+
I can do whatever I want.
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 4
Protocol-specific semantics forces the forwarding elements (FE) to understand the packet formats and retain the specific packet processing knowledge. The reactive evolving path needs incessant standard revisions to accommodate new features and new protocols.
Plane coupling Protocol/instruction explosion Stateless/Limited expressivity
Current OpenFlow-enabled Device is a “Gray Box”
New service required
Does the OF Spec. support it?
Wait for new revision of OF Spec.
Wait for the device upgrade to support the new spec.
Deploy the software to enable the service
Yes
No
Idea
l path
Not future-proof Slow innovation process
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 5
SDN Computer System
APISys. Call
DriverInstruction Set
Computer system components have been decoupled from the vertical integration model. SDN is on the track to mimic this transition. But current OpenFlow still doesn’t embrace this model to the full extent.
SDN: Operate your Network Device like a PC
Simple & generic instruction set
Ultimate flexibility & extensibility
Upgrade only on performance
Service
Controller
Forwarding Element
Application
OperatingSystem
CPU systemPeripheral
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 6
Protocol Oblivious Forwarding: Core Concept
OFPAT_COPY_TTL_OUTOFPAT_COPY_TTL_INOFPAT_SET_MPLS_TTLOFPAT_DEC_MPLS_TTLOFPAT_PUSH_VLANOFPAT_POP_VLANOFPAT_PUSH_MPLSOFPAT_POP_MPLSOFPAT_SET_NW_TTLOFPAT_DEC_NW_TTLOFPAT_PUSH_PBBOFPAT_POP_PBBand on and on and on …
POFAT_SET_FIELDPOFAT_ADD_FIELDPOFAT_DELETE_FIELDPOFAT_MOD_FIELDPeriod.
~40 matching header fields defined yet still many uncovered protocols/headers
{offset, length} covers any frame based formats
Packet field parsing and handling are abstracted as generic instructions to enable flexible and future proof forwarding elements. This is simple yet has profound implications to SDN.
Match
Action
Current OpenFlow POF
Table search keys are defined as {offset, length} tuples
Instructions/Actions access packet data or metadata using {offset, length} tuples
Include other math, logic, move, branching, and jump instructions
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 7
Is this an IP packet?
Use destination IP to search FIB
Process TTL
Update Checksum
Data @ {12B, 2B} = 0x0800?
Extract Data @ {30B, 4B}; Use it as key to search LPM table x
Decrement Data @ {22B, 1B}; If result is 0, drop the packetClear Data @ {24B, 2B};Use algorithm y to calculate checksum over Data @ {14B, 20B}; Write result @ {24B, 2B}
DMAC SMAC Type Payload FCS
Conventional FE
Forwarding Flow
POF Forwarding Flow
Ethernet/IPv4 Packet Format
OpenFlow’s high level semantics (“what”) is simple in communication but demands forwarding plane intelligence; POF’s low level semantics (“how”) moves all the intelligence up to the controller
How to Ask a Dumb FE to Do Smart Things
The fine-grained bit-level manipulations used to be hardcoded or micro-coded in the FE are now explicitly described by controller
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 8
Other POF Features to Enhance OpenFlow
key metadata
instructions
Flow Entry
Table Update
Table Search
FlowTable
InstructionExecutionModule
The flow metadata and data-path table manipulation instructions enrich the forwarding plane programmability and flexibility
Enable active & stateful data-path
• Add general flow-based metadata beyond counters• Statistics • Time stamps• Anomaly• Flow states
• Add data-path instructions that can create and modify flow tables• MAC learning• Active firewall• Dynamic load balancing• Controller offloading
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 9
Other POF Features to Enhance OpenFlow (cont’d)
These new features facilitate the efficient hardware implementation, otherwise it would be difficult or even impossible for FE to figure out the optimization opportunities.
Add entry-specific parameters and allow multiple flow entries share the same instruction block• Save instruction memory and enable fast updates
Treat statistics counters and flow metadata as shared resource pool and assign the resource to flow entries on demand • Aggregated and multi-purpose counters for statistics• Message communication vehicle for flows
Distinguish logical tables and physical tables • The same physical table used by multiple logical tables (e.g. IP/RPF, MAC
Learning/forwarding)• One physical table resource shared by multiple unrelated logical tables (e.g
TCAM, Hash)
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 10
POF-based SDN Architecture
Programming Languages
Compiler
Flow Instruction Set
Application API
• Programmable• Network
optimized
• Runtime & Remote reprogrammable
• Table driven & protocol blind
• Flow instruction set
• Flexible• Generic• Standard• Low level
instruction set
NPU
CPU
• High performance
Flex Flow Processor
ASIC
Novel Applications &Services
Protocol SpecificApplication
Protocol AgnosticTables/Instructions
Controller
FlowTables
POFInstructions
POF Data Path
OpenFlow+ Hardware Abstraction Layer
Driver
Con
trolle
rForw
ard
ing
Ele
men
ts
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 11
Controller Forwarding Elements
Based on Floodlight with POF extension
Open source, cross platform, Apache licensed, and Java-based software
POF System Prototypes
NP-based hardware implementation on NE5000E or NE40E router platform
Open source software switch on Linux server
POFGUI
POFManager
PMDatabase
Bypass Manager Module
Floodlight Provider(Controller)
OtherOFMessage
Process Modules
ProtocolOblivious
Forwarding
Controller Controller
OpenFlow Connection Management
Forwarding Engine Driver
ForwardingEngine
OpenFlow Connection Management
OpenFlow Parse OpenFlow Encap
Resouce of POFSwitch
ForwardingEngine
MPU
LPU
Switch Control Module
Resouce Module
Datapath Module
HUAWEI Core Router
OpenFlow Parse OpenFlow Encap
HAL of POF
POFSwitch
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 12
Using NPU to Implement POF
Proprietary NPU runs in RTC (Run To Completion) programming model Two modes for POF implementation
• Function Mode: Each FIS instruction is implemented in FE NPU as a function written in
micro-code. Each instruction is essentially a function call.
• Simple but has a performance hit
• Compiling Mode: Controller or the FE driver compiles the FIS instructions into NPU micro-
code directly and load the code to the program memory.
• Better performance but more complex
Current prototype used Function Mode and we are working on Compiling Mode• We see up to 30% performance loss
• Mainly due to table search key constructions
• Still satisfy typical application scenarios for the 40G line card
It is feasible to use NPU to implement POF, in the long run we prefer to have some POF-optimized silicon to reduce the cost and boost the performance.
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 13
L2IPv4 IPv6 MPLS…
NVGRE VXLAN TRILLIPXFibre Channel…
User DefinedSource Routing NDNCCNSCN…
Network Service Enabling
VPLS, Stateful Firewall, DPI, L4~L7 Applications
Forwarding Protocol Enabling
Other innovation possibilities
Network processing simplification - reduce tunneling and transformation
User defined scratch space in packets for in-band info communication (OAM)
POF Use Cases
POF offers unmatched flexibility to the forwarding plane. With it, we can either deploy sophisticated network services or greatly simplify the network forwarding process.
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 14
Define low-level instruction set FIS• Platform-independent generic primitives
• Expressive for a wide range of applications
• Programming in “assembly” style
• Allows layered abstraction and virtualization
• No need to be the same as the chip instruction set
Standardization is the key• Stabilize a future-proof OpenFlow specification (OpenFlow 2.0?)
• Need industry-wide collaboration involving all the player
• Many hard problems (technical and non-technical) to attack
• We publish the open-source website to advocate open research and
encourage contributions and adoptions
• POF has the potential to truly commoditize the forwarding elements while nourishing an independent controller/application software market.
How to realize POF
www.poforwarding.org
HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential 15
POF thoroughly decouples the SDN control plane and the forwarding plane
• Controller-side software can construct flexible applications without any underlying
constraints
• Controller applies high level languages and compilers to program the FEs through the
standard instruction set
POF advocates a standard, flexible and future-proof forwarding plane• Allow FEs to focus on performance rather than functionality
• FE will become simpler and more flexible
POF calls for continuous research to improve• Standardize the interface and the FIS, leave the other details for innovation
Conclusions
Service providers will benefit from this technology through:(1) using standard, simple, and future-proof FEs to save CAPEX/OPEX (2) quickly deploying customized and innovative services in the form of application software to generate new revenues.
Thank youwww.huawei.com
Copyright©2013 Huawei Technologies Co., Ltd. All Rights Reserved.The information in this document may contain predictive statements including, without limitation, statements regarding the future financial and operating results, future product portfolio, new technology, etc. There are a number of factors that could cause actual results and developments to differ materially from those expressed or implied in the predictive statements. Therefore, such information is provided for reference purpose only and constitutes neither an offer nor an acceptance. Huawei may change the information at any time without notice.
For more information, please go to www.poforwarding.org and subscribe ONF SDN-Future Discussion Group mailing list.