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Technical white paper

Converged Networks and Fibre Channel over Ethernet
Table of contents Abstract Introduction Converged networks Data Center Bridging Fibre Channel over Ethernet (FCoE) Challenges for end-to-end network convergence Servers Direct-attach storage Storage Area Network iSCSI: SANs using TCP/IP networks Cluster interconnects Approaches to converged data center networksConvergence strategies Cost structure Congestion and flow control FCoE and DCB progress and challenges ahead Using HP Flat SAN technology to enhance single hop FCoE Evolution of storage Conclusion For more information 2 2 2 3 3 4 4 5 5 5 5 5 6 7 7 8 9 10 11 12

Abstract
In this paper we examine requirements for converged networking up to the server edge and beyond for end-to-end network environments.We want you to understand how the HP vision for converging technology, management tools, and partner product portfolios aligns with those requirements. We also compare HP and Cisco approaches to converged networking so you can see the likely outcomes of the two strategies. If you are a senior executive, CTO, CIO, IT manager, or business manager looking to deploy end-to-end converged networks in thenext few years, this white paper can help you make more informed decisions about converged networking in your IT environment.

Introduction
Traditional data centers typically have underused capacity, inflexible purpose-built resources and high management costs. Infrastructure designs in such data centers include separate, heterogeneous network devices for different types of data. Each deviceadds complexity, cost, and management overhead. Many data centers support three or more types of networks and therefore require unique switches, network adapters, and network management systems to unify the networks. Network convergence in the data center is a simpler and more economical solution than using separate purpose-built networks for data, management, and storage. Network convergencesimplifies data center infrastructure by consolidating block-based storage and traditional IP-based data communications networks onto a single converged Ethernet network. To achieve network-wide convergence, the IT industry has proposed and ratified the IEEE 802.1 Data Center Bridging (DCB) network protocol standards. The industry as a whole is deciding which implementation paths to pursue. In thispaper we look at issues and choices IT organizations and vendors face when implementing these standards in networking products and data center infrastructures.

Converged networks
To better understand the current state of data center networking and the difficult tradeoffs facing IT organizations today, we should look at FCoE and DCB network standards. Protocol standards ratified by the IEEE 802.1Data Center Bridging Task Group 1 affect network hardware, architecture, and behavior in converged end-to-end network infrastructure. Attempts to create end-to-end converged networks over the past decade have used the Fibre Channel Protocol, InfiniBand, and iSCSI. All have found their place in the market; but for both technological and business reasons, none have gained widespread acceptance asthe Converged Network standard. In compliance with ratified industry standards, HP has successfully implemented converged Fibre Channel over Ethernet (FCoE) networks at the server edge using top-of-rack (ToR) switches, Virtual Connect (VC) FlexFabric module, FlexFabric Adapters, and Converged Network Adapters (CNAs). The server edge is the first hop for networks in multi-hop or multiswitch networkenvironments. The next major challenge is to extend that convergence throughout the data center network. Figure 1 shows a single DCB-compliant network carrying IP, storage (FCoE), and cluster traffic using RDMA over Converged Enhanced Ethernet (RoCEE). You can read more about RoCEE and the expected trends in clustering in the “Cluster interconnects” section later in this paper.
Figure 1:...