Data Center Ethernet Overview 25Oct08

8/14/2019 Data Center Ethernet Overview 25Oct08

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2008 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialDCE Overview 1

Posted to the Cisco Learning Network - www.cisco.com/go/learnnetspace

Data Center Ethernet(DCE)


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Data Center Networking Environment

Clustered and grid applications are becoming more common

Multicore CPU architectures and server virtualization are driving theneed for more bandwidth per server

Network traffic is:

Client to server, server to server, server to storage, and storage tostorage

Higher dependency of application performance on network performance

Bandwidth and latency matter

Traffic characterization includes:

Short burst messages: Client to server and server to server

Long steady messages: Server to storage and storage to storage

Packet drop affects most traffic types

Flat networks are common


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Increased Efficiency, Simpler Operations

UnifiedFabricUnifiedFabric

Unified Fabric and I/OUnified Fabric and I/O

Storage

Network

StorageNetwork

MgmtNetwork

MgmtNetwork

BackupNetworkBackupNetwork

Back-End

Network

Back-End

Network

Front-EndNetwork

Front-EndNetwork


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Key Benefits of Unified Fabric

Reduce overall data power consumption by up to8%. Extend the life cycle of current data center.

Wire hosts once to connect to any networkSAN,LAN, HPC. Faster rollout of new applications and

services.

Every host can mount any storage target. Drivestorage consolidation and improved utilization.

Rack, Row, and X-Data Center VM portabilitybecome possible.


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What Is Data Center Ethernet?

Data Center Ethernet (DCE) is an architectural collectionof Ethernet extensions designed to improve Ethernet

networking and management in the data center.

Cisco is showing innovation while working through thestandardization process with these extensions in open

standards forums.


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Provides ability to transport various traffic types (e.g.storage, Remote Direct Memory Access [RDMA]).

Lossless Service

Eliminates spanning tree for Layer 2 topologies.Uses full bisectional bandwidth with Equal-Cost Multipath (ECMP).

Layer 2 Multipath forUnicast and Multicast

Autonegotiation for Enhanced Ethernet capabilities.Data Center Bridging Exchange (DCBX).

Data Center BridgingCapability ExchangeProtocol

End-to-end congestion management for Layer 2 network.Congestion Notification(BCN/QCN)

Groups classes of traffic into service lanes.Enhanced Transmission Selection (IEEE 802.1Qaz).

CoS-based BandwidthManagement

Provides class of service (CoS) flow control.Able to support storage traffic.

Priority-based FlowControl (PFC)

BenefitFeature

Data Center Ethernet FeaturesOverview


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Data Center Ethernet Features

Enables lossless fabrics for each class of service PAUSE sent per virtual lane when buffer limit exceeded Network resources are partitioned between virtual lanes

(e.g. input buffer and output queue)

Switch behavior is negotiable per virtual lane

Priority-Based Flow Control (PFC)Priority-Based Flow Control (PFC)


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Enhanced Transmission Selection (ETS)Enhanced Transmission Selection (ETS)

Enables intelligent sharing ofbandwidth between traffic classes;control of bandwidth

Being standardized in IEEE 802.1Qaz Also known as priority grouping


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Congestion ManagementCongestion Management

Moves congestion out of the core to avoid congestion spreading Allows end-to-end congestion management Standards track in 802.1Qau


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Data Center Bridging Capability Exchange ProtocolData Center Bridging Capability Exchange Protocol

Hand-shaking negotiation for: CoS bandwidth management Class-based flow control Congestion management (BCN/QCN) Application (user_priority usage)

Logical link down

Data Center Ethernet

Data Center Ethernet


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Layer 2 MultipathingLayer 2 Multipathing

LAN

Active-Active

MACB

MACA

MACA

MACB

LAN LAN

VPC

L2 ECMP

L2 ECMP

Phase 1Phase 1 Phase 2Phase 2 Phase 3Phase 3

Eliminates STP on uplink

bridge ports Allows multiple active

uplinks to switch to network Prevents loops by pinning a

MAC address to only oneport

Completely transparent tonext hop switch

Virtual switch retains physicalswitches independent control anddata planes

Virtual port channel mechanism istransparent to hosts or switchesconnected to the virtual switch

STP as fail-safe mechanism toprevent loops even in the case ofcontrol plane failure

Uses Intermediate System-

to-Intermediate System (IS-IS)-based topology

Eliminates STP from Layer 2domain

Preferred path selection

VirtualSwitch


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Summary

A unified fabric is the end-state networkwhere LAN, storage area network (SAN), and

interprocess communication (IPC) traffic areconverged onto a single networkinfrastructure.

Data Center Ethernet (DCE) is thefoundation for delivering a unified fabric.DCE will also appeal to customers who arenot planning for consolidated I/O due to itsLayer 2 multipathing capabilities and itslossless service behavior.

DCE comprises a set of Ethernetenhancement standards that adhere to theemerging IEEE data center bridgingspecification.

Data Center Ethernet Overview 25Oct08

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