SDN Enabled DCB Configuration

Elastic QoS by Controlling Link Level DCB Primitives

Dell Enterprise Service Group

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Agenda

• What is DCB?

• Problems

• SDN Advantage

• Use Cases

• Demo

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Data Center Bridging (DCB)• DCB Definition• Ethernet Enhancement for data centers• Best Effort Lossless-ness• Convergence: Running Fiber Channel over Ethernet

• Primitives• Priority Flow Control (PFC) – IEEE 802.Qbb• Enhanced Transmission Selection (ETS) – IEEE 802.Qaz• Congestion Notification (CN) – IEEE 802.1Qau

• Control• DCB-Exchange Protocol (DCBX)• New TLV Fields in LLDP• Peer2Peer (Port Level)

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Bandwidth Allocation in

Egress Queues

70%20%10%

Ingress Traffic

Types by dot1p

Priorities

ETS Priority Groups:LAN: 0,1,2,5,6,7SAN: 3IPC: 4

10 GigE

4

Link Level Primitives• Priority Flow Control• Receiving station sends Pause

Frames• Uses well-known Multi-cast MAC• Quanta – Num of 512 bits to wait

• Enhanced Transmission Selection• Assign priorities to application

classes• Manage traffic priority to the app• Allocate bandwidth to the classes

• Congestion Notification• L2 End-to-End Cong. Notification• Requires Enabling on entire data-

path• Switches in-patch can send CN

frames

Receive Buffers

PFC Pause Frame sent

only for Priority 3

Traffic

Dot1p Priorities as Virtual Transmit Queues

76543210

10 GigE

1

2

3

4

2Gbps

2Gbps

2Gbps

1GbpsCN

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Problems• Configuration Issues• Static Port to Port – Multihop is

complex• DCBX-TLVs carry config params• DCBX unsupported on end-hosts

• Interoperability Issues• Not Uniformly Implemented • QCN not required for PFC/ETS• Hence DCB perceived confusing

• Inflexible and Non-Scalable• DCB capabilities may be sparse• Wasted Switch Resource if Unused• Associated only with Storage

Legacy Config

XX

Legacy Config

X X

Legacy Config

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SDN Advantage• Centrally Program/Configure

Primitives• Removes need for DCBX• Supports End host Config• Eliminate Willing/Non-Willing Modes

• Interoperability Simplified• Heterogeneous Friendly• Switches advertise capabilities • Actively Probe, Verify and Configure

• Flexible and Scalable• Dynamically Reconfigure Paths• Optimized use of resources• New QoS functions – Lossless Paths

Legacy ConfigSDN Controller

Legacy ConfigSDN Controller

Legacy ConfigSDN Controller

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• Simplify and Enable Multi-Hop Environments• Move Data effortlessly between SANs

• Lossless-QoS For Granular Flows in Multi-Tenant Environments• Prioritize SQL query on iSCSI for RED over BLUE• …Over Email Backup on iSCSI SAN 2 for BLUE-Tenant

Use Cases

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Demo

• Demo Setup

• How we test/tools etc.

• Verification

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Demo SetupStack Diagram Demo Topology

App (Elastic DCB)

OF-Controller(POX Modified)

OF-Switch(DCB Extensions)

OFPT_PORT_MODExtensions

Ethernet Ports

Program DCB Primitives

pssh

iperfclients

iperfserver

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Sample DCB Configuration• DCB Configuration Profile 1• ETS

ets tc_tx_bw: 90 10 0 0 0 0 0 0ets tc_rx_bw: 90 10 0 0 0 0 0 0ets tc_tsa : 2 2 0 0 0 0 0 0ets prio_tc : 0 1 2 0 0 0 0 0

• Demo Instruments Few Such Profiles• ETS

ets tc_tx_bw: 90 10 0 0 0 0 0 0ets tc_tx_bw: 70 30 0 0 0 0 0 0ets tc_tx_bw: 50 50 0 0 0 0 0 0ets tc_tx_bw: 30 70 0 0 0 0 0 0ets tc_tx_bw: 10 90 0 0 0 0 0 0

90% B/W* on P0 Traffic110% B/W* on P1 Traffic

*Minimum Guarantee

TSA – transmission selection algorithm

ETS – priority 0 and 1

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Applying Profile 1, Different Tests

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Summary

• DCB Primitives via SDN/OpenFlow

• Eliminated need for DCBx

• Created New QoS/Classes