Cisco Cisco Nexus 5010 Switch White Paper
.
White Paper
© 2009 Cisco Systems, Inc. All rights reserved. This document is Cisco Public Information.
Page 1 of 9
Lossless 10 Gigabit Ethernet: The Unifying Infrastructure for SAN and
LAN Consolidation
LAN Consolidation
Introduction
As organizations increasingly rely on IT to help enable, and even change, their business strategies, they need their
IT infrastructure to be more powerful, agile, and cost effective than ever. Today’s enterprises require continual
system availability, demand ubiquitous access, and expect rapid and fluid responses to their ever-changing business
needs.
To provide these functions, enterprise data centers are challenged to get more use out of existing resources and
operate quickly, with increased agility. Specifically, they must address the following data center challenges:
●
Improve asset utilization to reduce or defer capital expenses
●
Reduce power and cooling consumption to cut costs and align with green business practices
●
Reduce time to market for infrastructure and applications
●
Make data and resources available in real time to provide flexibility and alignment with current and future
business needs
To meet these challenges, organizations must build a single network infrastructure that unifies traditional server I/O,
storage, and network operations to more efficiently support evolving business applications. This document describes
how a Unified Fabric, proposed by Cisco and NetApp, enables convergence of SAN traffic over an Ethernet and
compares the performance of Fibre Channel over Ethernet (FCoE) to native Fibre Channel.
Today’s Storage Network
Most large data centers have a separate, dedicated storage network, called a SAN, using Fibre Channel. Fibre
Channel SANs connect servers to shared block storage systems through a dedicated high-speed network of host
bus adapters (HBAs) and switches. The resulting storage network allows servers and storage to communicate, and
multiple pathways can be established to help ensure storage availability by enhancing redundancy and improving
performance. SANs have traditionally employed the Fibre Channel protocol using the physical implementation and
signaling detailed in ANSI standard X3.230-1994 (ISO 14165-1). Fibre Channel uses optical fiber, coaxial copper, or
twisted-pair copper cabling to carry SAN data over interswitch links (ISLs) at speeds of 1, 2, 4, and 10 Gigabits (Gb),
and more recently, 8 and 20 Gb. Fibre Channel can operate in point-to-point, switched, and loop modes, with
switched mode prevalent.
The cost and complexity of Fibre Channel kept SAN deployments out of reach for most small and midsized
businesses (SMBs) until the introduction of SANs based on the Small Computer System over IP (iSCSI) protocol
ratified by the IETF in 2003. An iSCSI SAN typically employs network interface cards (NICs), an iSCSI software
driver, and Ethernet switches in a segregated network. Every major operating system includes an iSCSI driver in its
distribution. iSCSI performance can be improved by deploying Ethernet NICs with a TCP/IP offload engine to reduce
the CPU demands for TCP/IP processing. Given that iSCSI uses the standard SCSI command set and IP network,
interoperability is well understood and straightforward. Currently, the vast majority of iSCSI SANs operate at 1 Gb
Ethernet speeds; however, 10 Gigabit Ethernet NICs, switches, and storage systems are available today, and as
costs continue to come down, 10 Gigabit Ethernet solutions will become more widely deployed.
A third popular form of storage is network attached storage (NAS). NAS consists of a server connecting the storage
to the TCP/IP network and enabling users to access the storage by using either the Microsoft Common Internet File