NEW-GENERATION SERVER TECHNOLOGYThe ALB architecture uses knowledge of Layer 3 information, suchas IP address, to achieve optimum distribution of the server transmissionload.ALB is implemented by assigning one of the physical channelsas “primary” and all other physical channels as “secondary.”Packets leaving the server can use any one of the physical channels,but incoming packets can use only the primary channel. Whenenabled, RLB balances the IP receive traffic. The intermediate driveranalyzes the send and transmit loading on each physical adapterin the team and balances the rate across all adapters based on thedestination address. Adapter teams configured for ALB also providethe benefits of fault tolerance, as described in the “Adapter FaultTolerance” section in this article.Static Link AggregationLink aggregation is similar to ALB in that it combines several physicalchannels into one logical channel. The Intel intermediate driversupports link aggregation for FEC and GEC.FEC is a trunking technology developed by Cisco to aggregatebandwidth between switches working in Fast Ethernet. UsingFEC, administrators can group multiple switch ports together toprovide additional bandwidth. Switch software treats the groupedports as a single logical port. Administrators can connect anend node, such as a high-speed server, to the switch using FEC.The <strong>Power</strong>Edge 1855 bladeserver can be configured toprovide a highly redundantnetwork environmentwhen plugged into a singleexternal switch.FEC link aggregation providesload balancing in a similarmanner to ALB, including theuse of the same algorithm inthe transmit flow.The transmission speedfor FEC does not exceed theadapter base speed to anysingle address; teams mustmatch the capability of theswitch. Adapter teams configuredfor SLA also providethe benefits of fault toleranceand load balancing. When using SLA mode, administrators arenot required to set a preferred primary adapter. All adapters inan SLA team must run at the same speed and must be connectedto an SLA-capable switch. If the speed capability of adaptersin an SLA team is different from the speed of the switch, thespeed of the team is dependent on the switch. SLA teamingrequires that the switch be set up for SLA teaming and that STPbe turned off.GEC link aggregation is essentially the same as FEC linkaggregation, except that GEC supports 1000 Mbps speeds versus100 Mbps for FEC.IEEE 802.3adIEEE 802.3ad is the IEEE standard for the technology incorporatedin the Cisco FEC standard. Intel’s intermediate driver support forIEEE 802.3ad is similar to its FEC and GEC support. Administratorscan configure a maximum of two IEEE 802.3ad dynamic teams perserver, and the configuration must use 802.3ad-capable switches indynamic mode. Adapter teams configured for IEEE 802.3ad also providethe benefits of fault tolerance and load balancing. The 802.3adteaming mode allows all network communication protocols to beload balanced.Dynamic mode supports multiple aggregators, and adaptersshould operate at the same speed. Only one team can be activeat a time.The advantages of modular computingThe <strong>Dell</strong> <strong>Power</strong>Edge 1855 blade server can help organizationsdeliver on the promise of modular computing—namely loweracquisition cost, lower total cost of ownership, rack density,and power efficiency—all without trading off enterprise-classfeatures. Moreover, by understanding the unique aspects ofthe <strong>Power</strong>Edge 1855 blade server’s architecture, as described inthis article, administrators can create a highly reliable networkinfrastructure.Mike J. Roberts is responsible for blade server product planning at <strong>Dell</strong>. Mike has a B.A.from Marquette University and an M.B.A. from The University of Texas at Austin.Doug Wallingford is a sustaining engineer in the Enterprise International Product Supportdepartment at <strong>Dell</strong>. Doug has 14 years of experience in network field support, seven yearsas a Xerox field engineer, and seven years at <strong>Dell</strong>. He has numerous Microsoft and Novell certifications—including Microsoft Certified Systems Engineer (MCSE), Microsoft CertifiedSystems Administrator (MCSA), and Certified Novell Administrator (CNA).Balaji Mittapalli is a development engineer in the Server Networking and Communicationsdepartment at <strong>Dell</strong>. Balaji has an M.S. in Electrical Engineering from The University of Texasat San Antonio and a B.S. in Electronics and Communication Engineering from S.V. Universityin India. Balaji’s areas of interest are wired and wireless networks.Visit <strong>Dell</strong> <strong>Power</strong> <strong>Solutions</strong> online at www.dell.com/powersolutions28POWER SOLUTIONS Reprinted from <strong>Dell</strong> <strong>Power</strong> <strong>Solutions</strong>, February 2005. Copyright © 2005 <strong>Dell</strong> Inc. All rights reserved. February 2005
More data? Less time?No problem.<strong>Dell</strong> LTO-2 products keep pace with your growing backup needs.Your organization’s data may be increasing exponentially, but your backup window isn’t. Chances are, yourIT staff must perform backups overnight in only four to five hours—no matter how much data is involved.<strong>Dell</strong> helps enterprises meet the challenges of rapid data growth and shrinking backup windows with the <strong>Dell</strong> <strong>Power</strong>Vault series of Ultrium ® 2 LTO (LTO-2) tape backup products. Featuring powerful second-generationLinear Tape-Open (LTO ® ) technology, <strong>Dell</strong> LTO-2 products are optimized to provide both speed and capacity:Outstanding performance: A data transfer rate of up to 70 MB/sec. 1High-capacity media: Up to 400 GB capacity per cartridge can mean fewer cartridges to purchase<strong>Dell</strong> <strong>Power</strong>Vault 132T tape librarywith LTO-2 tape drivesand store, which can help save you money. 2Open standards: LTO open standards foster competitive pricing and a format that has broadindustry acceptance.Best of all, the LTO roadmap projects the potential todouble capacity and performance in each successivegeneration, and supports comprehensive backwardcompatibility. 3 <strong>Dell</strong> LTO-2 drives are available in the<strong>Power</strong>Vault 110T (as a stand-alone unit or configuredinternally on select <strong>Power</strong>Edge servers) and in<strong>Dell</strong> <strong>Power</strong>Vault 132T, 136T, and 160T LTO-2 tapelibraries. To learn more, visit www.dell.com/storage.<strong>Dell</strong> <strong>Power</strong>Vault 110T LTO-2 tape driveand 136T, 160T LTO-2 tape librariesEasy asClick www.dell.com/storage1 Assumes 2:1 compression. Data compression rate may vary depending on settings, user environment and applications.For more information, visit http://www1.us.dell.com/content/products/productdetails.aspx/pvaul_110tlto2?c=us&cs=555&l=en&s=biz&~tab=specstab#tabtop.2 Assumes 2:1 compression. Data compression rate may vary depending on settings, user environment and applications. For more information about LTO format and capacity, visit http://www.lto.org/newsite/html/format.html.3 For more information about LTO technology and the LTO roadmap, visit http://www.lto.org.Linear Tape-Open, LTO, and Ultrium are trademarks or registered trademarks of Certance, International Business Machines Corporation, and Hewlett-Packard Company. <strong>Dell</strong>, the <strong>Dell</strong> logo, <strong>Power</strong>Edge, and <strong>Power</strong>Vault are registered trademarksof <strong>Dell</strong> Inc. ©2004 <strong>Dell</strong> Inc. All rights reserved.
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