Show 47 – Load Balancers – Good Thing We Didn’t Step In It

Value market versus Enterprise Market

There is the load balancing market that most in networking are aware of, with vendors like Cisco and F5, and then there is the value market. Load balancers you can get for $2,500-$10,000 a piece (redundant coming in at around $5K to start, USD of course) that have many of the features of the big boys, but not necessarily the reputation. KEMP, Barracuda, just to name a few.

The double-edged sword of content manipulation (iRules, aFlex, etc.)

The benefit of iRules is that they can manipulate HTTP content and add application logic to the network layer. The drawback is that they can manipulate HTTP content and add application logic to the network layer.

It’s always the load balancer Load balancers get blamed disproportionately for issues. Although, sometimes it is the load balancer.

It’s 2011, why is DNS-based Global Server Load Balancing still my only option in most cases?

Will load balancers be the front line for the IPv6 conversion? IPv6 VIPs, IPv4 servers?

HTTP: The Undertaught Protocol

TCP One Connect / Session Termination – performance, security and design decoupling.


Load balancers versus Application Delivery Controllers (terminology and common parlance). It’s “Load Balancer” and never ADC. Vendors are pushing to call these devices Application Delivery Controllers, ADCs. I don’t think that name has stuck very well. Everyone I know calls them load balancers, and if I say ADC no one knows what I’m talking about. ADC is as meaningless as the word “cloud”

Hosts / Guests

Lori MacVittie | Twitter: @lmacvittie

Tony Bourke | Twitter: @tbourke

Ethan Banks | Twitter: @ecbanks

and last, and the very least:

Greg Ferro| Twitter @etherealmind


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Greg Ferro
Greg Ferro is a Network Engineer/Architect, mostly focussed on Data Centre, Security Infrastructure, and recently Virtualization. He has over 20 years in IT, in wide range of employers working as a freelance consultant including Finance, Service Providers and Online Companies. He is CCIE#6920 and has a few ideas about the world, but not enough to really count. He is a host on the Packet Pushers Podcast, blogger at and on Twitter @etherealmind and Google Plus.
Greg Ferro
Greg Ferro
Greg Ferro
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  • Michael Schipp

    ADC vs Load Balancer

    ADC = bullsh1t name for sometinhg that most already know.


    End of the day no matter how much intelligence and security you add into your decision to choose where and why to send the traffic – you are balancing the traffic – therefore you are load balancing.

    End of story

    Sorry Brocade
    Sorry Cisco
    Sorry F5
    Sorry Rest of you

    A spade is a spade – deal with it.

  • Ross

    No one had nothing to say about Elfiq? Bang for buck it is worth a look no??

  • tbourke


  • Markh

    I loved the discussion/rant on the terminology ACD vs. LB since a ‘bright spark’ where I work named the gaggle of people who design around the F5’s “Content Delivery Group” (or words to that effect). Of course when a manager does this noone is going to admit they don’t know what they mean (including F5 gurus). 
    I completely agree that these ‘things’ do more that load balancing (eg. TCP optimization is not load balancing) and I believe ADC is a more technically correct term than load balancers, but one question … when’s the last time the the thing we now call a router had it’s name changed to more technically accurately encompass it’s expanding set of features?

    • Etherealmind


  • ganesh

    so if http is undertaught – how about providing some links to where folks like me (who are really infrastructure guys who like to learn more from the experts in networks) can really learn more? thanks!!

    • Etherealmind

      Google is your friend, or look at buying some O’Reilly textbooks.

      • Markh

        With all due respect to you & your fine podcast, replies like that REALLY annoy me.

        Ganesh – try,

        • Etherealmind

          Wasn’t meant to be annoying, I just don’t have any links or recommendations, nor time to look for some. I’d rather acknowledge the question than ignore it completely.

          Good links though. Thanks.

          • Markh

            Sorry Greg … tortured memories of cisco SEs telling me “it’s on the web” :)

          • Etherealmind

            Actually, it would make a good blog post. Don’t suppose you got any more sggestions on links for learning HTTP, SMTP, FTP et al ?

        • Ganesh

          thanks for the links to the web based training! i will give them a whirl this evening from home!

        • Ganesh

          thanks for the links to the web based training! i will give them a whirl this evening from home!

        • Gsh

          thanks for the links to the web based training! i will give them a whirl this evening from home!

        • Ganesh

          sorry about the repeat posts – it kept coming up with “system error” and ended up posting all the retries…..

  • Chris Welsh

    This has got to be one of the BEST packet pushers podcasts yet. And I find too that more and more I have to tell people to get acquainted with HTTP – I see exactly what your argument is.  I’ve just finished teaching a WAAS class (now there’s another great topic you could drag out) and honestly, most of the students didn’t know if CIFS was TCP or UDP based.  We have to get our engineers to see beyond layer 3.

  • Michele Chubirka

    I set up the original load-balancing infrastructure where I work. The most important lesson I can offer is that the enterprise has to be ready for the introduction of load-balancing into its infrastructure. Today’s devices have very advanced features including caching and connection multiplexing that can positively or negatively impact content delivery. That means that the application developers, systems and networking teams have to be ready to make a paradigm shift into a new way of thinking and working together. The application is now a logical entity with the load-balancer becoming part of the SDLC process.