Challenges on FCoE and DCB Network · PDF fileChallenges on FCoE and DCB Network Testing . ......

Storage Developer Conference 2009 © 2009 Insert Copyright information here. All rights reserved.

© 2009 Finisar Corporation

Challenges on FCoE and DCB Network Testing Joy Jiang

Product Line ManagerJDSU


Agenda

Next generation data center networks: Data Centers and I/O ConsolidationTechnology review: DCB (Data Center Bridging) and FCoE (Fibre Channel over Ethernet)Testing challenges on DCB and FCoE

Testing focus from design to deployment Test case examplesConclusion

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Storage Developer Conference 2009 © 2009 Insert Copyright information here. All rights reserved. 3

Internet

Current Data Center Structure

IPC

FC SAN B

FC SAN A

LAN

Hosts

Storagedevices


Traffic Type: SAN (Storage Area Network)

Based on Fibre ChannelTransport data between storage devices and serversdeterministic, in-order, guaranteed deliveryLow latencyHigh I/O performanceLimited scalability and high costs


Traffic Type: LAN (Local Area Network)

Based on EthernetData communications between users to servers and servers to serversSimple structure and low costsEase to scale Best effort service, guaranteed delivery managed by upper-layer protocolsNeed QoS to improve latency


Traffic Type: IPC (Inter-Process Communication)

Based on low latency protocolsData communication between server to server in a cluster environmentExtremely low latencyLimited scalability due to physical distanceMinimum flow control


FCoE

GE

FC

Internet

Next Generation Data Center: Converged Ethernet

FC SAN B

FCSAN A

LAN

Hosts

Storagedevices

Enhanced Ethernet

StorageIPCLAN


FC TrafficFC HBA

I/O Consolidation in the Host

Replacing NICs, HBAs and HCAs with fewer CNAs (Converged Network Adapters) Promise of lower TCO: cost, power, support, etc

All traffic goes over

10GE

CNA

CNA

FC TrafficFC HBA

NIC Enet TrafficNIC Enet Traffic

NIC Enet Traffic

HCA IPC Traffic

IPC TrafficHCA

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Network Management Challenges on Converged Network

To manage different traffic types and achieve individual performance goals, simultaneously


Test Challenges on Converged Network

Different test interests in LAN and SAN Networking only versus comprehensive verificationQoS best effort versus stringent traffic flow controlA new dimension of performance and latency requirements

Key to the success of Enhanced Ethernet is a thorough understanding of critical traffic flows such as storage data and IPC data

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Technology Review

DCB and FCoE

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Data Center Bridging (DCB)

What is DCB?Major enhancement of current Ethernet to be able to handle multiple traffic types in a converged networkDCB is the IEEE task group defining the enhancements

Ability to coexist both “lossy” and “lossless” types of trafficAbility to provision and guarantee bandwidth to different types of trafficAbility to manage long term congestion and congestion spreading

Why DCB?To manage converged networksTo meet lossless QoS and low latency requirements for different types of trafficOptimizing overall performance of converged networks

DCB Projects:IEEE802.1Qbb: Priority-based Flow Control (PFC) IEEE802.1Qaz: Enhanced Transmission Selection (ETS) and Data Center Bridging eXchange protocol (DCBX)IEEE802.1Qau: Congestion Notification (CN)

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DCB Protocols: PFC and ETS

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Priority-based Flow Control (PFC)

Enhanced Transmission Selection (ETS)

Provides traffic flow management, similar to Buffer-to-Buffer flow control in Fibre Channel, but per-Priority

Setup the minimum guaranteed bandwidth among different priority groupsDynamically optimize bandwidth utilization among virtual links


DCB Protocols: DCBX and CN

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Data Center Bridging eXchange (DCBX)Congestion Notification (CN)

Link-layer protocol to setup the priorities, priority groups and traffic classes for PFC and ETS♦On detecting “long-term” congestion,

a switch notifies end stations to rate limit the traffic to prevent congestion spreading throughout the entire network


Fibre Channel over Ethernet (FCoE)

What is FCoE?Enables Fibre Channel data to be transmitted over DCB EthernetOne-to-one mapping of an entire FC frame into an Ethernet frameData integrity is achieved by enhancing Ethernet at the link level to provide the same service of Fibre Channel links (i.e., no frame loss due to congestion)

Why FCoE?Seamlessly connects servers to existing SANs through Ethernet (no change to SAN appls)Expands the capability of FC, while lowering total costs of ownershipEnables converged Ethernet networks

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FCoE Header

FCHeader

Data FCCRC

Eth.Header

Data Eth.CRC

FC frame

Ethernet frame

FCoETrail

Ratified in May’09


Testing challenges on

DCB and FCoE

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Mandatory Testing for Lossless Virtual Links

Critical storage data has no tolerance on packet lossesFibre Channel is Lossless thanks to its link level buffer-to-buffer flow controlFCoE is a frame-by-frame mapping technologyLossless links are then required by FCoE trafficThe PFC protocol allows to carry lossless FCoE traffic with other lossy types of traffic over an Ethernet link

Testing challenges Focus on testing lossless property of virtual link and verifying “zero packet drop” characteristicsFocus on testing the short term versus long term congestion management

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Need for Hardware-Based Protocol Tools

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FCoE and DCB exchange information at protocol levelPFC flow controlETS bandwidth allocation for different traffic typesFCoE encapsulation/decapsulation process

High-speed data links create test challengesSoftware-based protocol analysis

Testing challengesFunctional test on FCoE and DCB Hardware-based protocol tester is needed throughout the design and deployment cycle

Guarantees 100% data capture and complete capability on testing FCoE and DCB

JDSU Xgig® Tester


FCoE Manages the Traffic as Fibre Channel

Gateway-less data management in FCoEData management controlled by FCP session – same as FC

Testing challengesWith FCoE, testing focus must shift from “E” to “FC”Measure the FC SAN performance over converged Ethernet environment

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FCfabric

iSCSIInitiator iSCSI

gatewayEthernet FC

Target

iSCSI sessionFCP sessionstateful

FCoEInitiator

FCoEmapperstateless

encaps/decapsFCP session


FC link

Mixed Link Interfaces in One Test Setup

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Mixed physical links and transport protocols in one networkFCoE maps native FC SAN to Ethernet

Testing challengeMixed and correlated protocol test: E to FCoE to FC and back again

Host with CNA

Enhanced Ethernet

FCoE switchFibre Channel

Fabric

Fibre Channel storage

10GE FCoE link10GE link

FC link

FCoE FCE


DCB Testing Under Network Congestion

DCB manages the performance of converged Ethernet networks

To achieve optimum latency, QoS and guaranteed delivery are implemented among different traffic typesPFC and ETS need to be tested under network congestion conditions

Testing challengesNeed generation tools to simulate link and network congestionNeed fast node emulation (server and storage) tools for device and network design and testing

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CN Network Testing Challenge

On detection of long-term congestion, switches in a CN controlled network generate CN messages toward end stations to rate-limit traffic

End stations: hosts and targets

Testing challengesNeed to create a long-term congestion situationNeed to verify the generation of CN messagesNeed to verify end stations react to the CN messagesNeed in-line testers to measure network to station performance

In-line traffic manipulation to create test casesTrace capture and analysis


Converged Benchmarking Test

DCB/FCoE enables network convergence in data centersLAN, SAN and IPC traffic on a singular Ethernet networkPerformance and benchmarking tests shall include different traffic types

Testing ChallengesThe current Ethernet benchmarking testing requires additions of metrics for SAN traffic

Full line-rate Protocol Analyzer is critical for storage data analysisRequires single platform for converged testing

Converged traffic generation (LAN+SAN) with different priority groups and traffic classes


Testing Focus from Design to Development

Indi

vidu

al D

evic

es • Functional verification

• Performance tests

• Protocol compliance

Syst

em In

tegr

atio

n • Interoperability• System level

performance verification

• Benchmarking tests

Dat

a C

ente

r D

eplo

ymen

t • Proof-of-concept tests

• Legacy structure integration tests

• Field maintaining services

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Test Case Examples

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Protocol Test Tools At-a-Glance

In-Line TestersProtocol Analyzer – capture and decode the traces and provide debug supportError injection – live traffic frame/packet manipulation and corruptionDelay emulation – traffic shaping and link latency emulation

Generation toolsGenerator – emulate host and target for end device functional testsLoad testing – emulate end nodes and generate full line rate traffic for switch/fabric performance testApplication test – emulate real world traffic by simulating real application traffic

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Test Case 1: Test PFC

Test Setup: Inject user defined PFC frame without saturating bandwidth to pause virtual link(s) and verify the PFC functions

Test Tools Used: Protocol AnalyzerError Injection - Jammer

Test Case Summary: Capable of testing individual devices with one setupAnalyzers verify the PFC behavior of each link end

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FCoE switchServer

CNA

Inject PFC to pause any traffic class at CNA Tx

Inject PFC to pause any traffic class at switch Tx

Analyzer AnalyzerJammer


Test Case II: Performance of FCoENetwork

Test Setup: Verify DCBX, ETS and PFC for link managementSetup FCoE to FC and FCoE to FCoE topologies to test FCoE frame mapping functionI/O generation tools for application based performance testTest Tools Used: FCoE and FC traffic generationProtocol AnalyzerI/O test softwareTest Case Summary: Single platform for testing DCB and FCoE networksAnalyzer to report the testing results on DCB characteristics in detailsI/O application based stress testing capable of simulation of real world traffic


Conclusion

The next generation data center networking trend is Converged EthernetThe new DCB and FCoE technologies have created new testing challenges

Change LAN test focus to SAN!Change focus from QoS to zero packet lossNeed hardware-based tools for high speed testingNeed in-line tools for comprehensive network testingNeed correlation between FC and Ethernet protocol testingNeed converged testing platform to combine LAN/SAN expertise

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