The Role of FCoE in I/O Consolidation
Joy Jiang
Finisar
1389 Moffett Park Dr
Sunnyvale, CA 94089
+1(408)542-4259
joy.jiang@finisar.com
Claudio DeSanti
Cisco
170 W. Tasman Dr
San Jose, CA 95134
+1(408)853-9172
cds@cisco.com
ABSTRACT
Consolidation of the multiple traffic types present in current data
centers over a single unified network is a big trend in the
information technology industry. Extensions to 10G Ethernet are
making it the most promising technology for achieving I/O
consolidation. The emerging Fibre Channel over Ethernet (FCoE)
protocol plays a critical role in this convergence process. This
paper elaborates how FCoE leverages the ubiquity and economics
of Ethernet networks while preserving the infrastructure,
strengths, and tools of the existing Fibre Channel Storage Area
Network (SAN) framework.
Categories and Subject Descriptors
C.2.5 [Computer Systems Organization]: Local and Wide-Area
Networks – Ethernet, high speed Fibre Channel.
General Terms
Management, Measurement, Performance, Economics,
Standardization.
Keywords
Fibre Channel over Ethernet, Fibre Channel, 10G Ethernet,
Lossless Ethernet, Unified network, I/O consolidation, I/O
convergence.
1. INTRODUCTION
I/O consolidation is the capability to consolidate the multiple
traffic types that today are carried over different data center
network infrastructures into a single network technology that
maintains the advantages of each existing traffic type while
minimizing the interactions among them. I/O consolidation
provides several cost benefits in terms of reduced number of
components required to build a data center and of associated
simplified management structures.
Fibre Channel (FC) is the preeminent technology used today for
storage networking. Among the reasons for its success we can list:
native support to map SCSI operations over Fibre Channel
protocol structures;
native protocol support for large data transfers; and
simplified protocol implementations due to the lossless
behavior of Fibre Channel networks (see 3.2).
However, in the Local Area Network (LAN) environment,
Ethernet is the dominant protocol. To consolidate LAN and SAN
into one unified network, it seems intuitive to enhance Ethernet to
make it able to natively carry Fibre Channel, so that the low cost
Ethernet may be the technology for the converged network [1].
In order to consolidate multiple traffic types over a single
network, that network has to provide enough bandwidth. 10G
Ethernet (10GE) is the best placed technology for consolidated
networks. However, its viability as a converged infrastructure is
dependent on the ongoing cost decay in the electronic and optical
components used at its physical layer. The information
technology industry has continuously brought down the cost of
these components and adoption of new protocols often depends
on this cost curve.
In this paper we discuss I/O consolidation, its benefits, its
requirements, and some technologies for achieving it, with a
special attention to the emerging Fibre Channel over Ethernet
(FCoE) protocol. In particular we describe FCoE, how it
compares with other protocols, and what benefits it brings to the
data centers in order to achieve I/O consolidation with minimum
impact on existing network structures. We also evaluate the status
of the FCoE protocol in terms of standardization, market interest,
products and tools availability.
2. I/O CONSOLIDATION
2.1 Overview
Conventional data centers operate up to three sets of parallel
networks, one for IP and local area networking (LAN)
applications, based on Ethernet, one for storage area networks
(SAN), based on Fibre Channel, and, in some cases, when high
performance computing (HPC) is deployed, one for the HPC
inter-process communications (IPC), based on Infiniband. These
three networks run separately from each other because of the
different application requirements they satisfy on data transfers
and transmission latency. In a sense they are optimized for the
specific applications they support. However, running three
separate infrastructures comes with significant costs for an
enterprise. Up to three different cabling systems, switching
infrastructures, and management frameworks need to be
maintained. As an example, it is quite common to find servers
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