Network Load Balancing

Discussion in 'Server Networking' started by Julien, May 28, 2008.

  1. Julien

    Julien Guest

    Hi,

    I got a problematic of network load balancing and I dont seem to find the
    tools to do what I wand on windows.

    Here is the situation, I got 2 network cards on my machine, connected on
    different subnet with different default gateway and I want the machine to do
    load balancing on those 2 interfaces. Actually I want the output traffic to
    be sent equally over those 2 interfaces.

    Im looking for a real load balancing solutions, not some workaround by
    splitting routing tables for exemple ...

    If you got suggestions ...

    Thx.

    Julien.
     
    Julien, May 28, 2008
    #1
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  2. Hi,
    think over your situation.

    if a client on subnet A requests data, the machine answers to that subnet A
    / to that client ( and i guess you want this).
    if the requested data were to the different subnet B, they would have a
    value (for the client - especially if there is no further routing) like they
    have been send to mars.

    you may have a research on "trunking".

    regards jk
     
    Juergen Kluth, May 28, 2008
    #2
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  3. Julien

    Julien Guest

    Well lets simplifiy. Imagine I got 2 network cards on my windows server and
    each one of those cards is connected to a different ISP. I just want the
    output traffic of the server ( an internet gateway for my LAN for exemple )
    to be load balanced equally between those 2 connections ... hope its clearer
    now.

    Thx for your answer by the way.
     
    Julien, May 28, 2008
    #3
  4. Won't happen.
    This has to be done at a router.

    If these are commercial lines (like T1s, D3, etc) this has to be a "real"
    router and will be done with routing protocols. It will involve the router
    at the ISP side and therefore requires that both lines come from the same
    IP. Typically the ISP performs this for you.

    If these are home user lines (DSL, CableTV) then this must be done with a
    broadband "router" that has two WAN ports and is designed for this purpose.

    Network Load Balancing in the Windows "context" is balancing "servers" as
    in clustering, mirroring, whatever term your want to use and has nothing to
    do with Lines and "connections".


    --
    Phillip Windell
    www.wandtv.com

    The views expressed, are my own and not those of my employer, or Microsoft,
    or anyone else associated with me, including my cats.
     
    Phillip Windell, May 28, 2008
    #4
  5. Julien

    Julien Guest

    Hi,

    Thx for your answers but actually im not sure we're clear about what I want
    to do. I dont want to load-balanced the input traffic, which I could have
    done with the solutions you suggested : DNS round robin ...
    What I want is to load-balanced the output traffic. If you want an exemple
    look at this howto for linux system :

    http://lartc.org/howto/lartc.rpdb.multiple-links.html

    The only thing is that I want to do the same thing on a windows server ...

    Thx again.

    Julien.
     
    Julien, May 29, 2008
    #5
  6. I didn't suggest DNS round robin,...and I wasn't speaking of inbound
    traffic. DNS round robin does not load balance at the outbound IP
    connection level or at the outbound packet level,...like what I was
    suggesting will do.

    Commercial Lines done as I described will balance both directions

    Home user lines done as I described will load balance only internally
    initiated outbound traffic.
    It is the way I said.

    --
    Phillip Windell
    www.wandtv.com

    The views expressed, are my own and not those of my employer, or Microsoft,
    or anyone else associated with me, including my cats.
    -----------------------------------------------------
     
    Phillip Windell, May 29, 2008
    #6
  7. Julien

    Julien Guest

    Hi,

    Sorry, I answered too quickly and I mut have msitaken your answer with
    another one somebody made me on another forum. Whatever.

    So to be clear for you there's absolutely no way to loadbalanced Home user
    lines directly from windows server ? I got to use specific network equipement
    to do that ?

    That seems strange as long as that problematic seems quite common , but i
    cant find anything on the web about such a solution so I begin to believe you
    actually ...

    Thx .
     
    Julien, May 29, 2008
    #7
  8. Windows can do "Dead Gateway Detection" which is a very "crude" form of
    Fail-Over (not load balancing)

    128978 - Dead Gateway Detection in TCP/IP for Windows NT
    http://support.microsoft.com/default.aspx?scid=kb;EN-US;128978

    171564 - TCP/IP Dead Gateway Detection Algorithm Updated for Windows NT
    http://support.microsoft.com/default.aspx?scid=kb;EN-US;171564
    It has been that way for years (about 10 years actually). So it is old news
    to those of us that have been with Windows for a long time. The generic
    TCP/IP Protocol, by itself, alone, just is not capable of such things.
    Therefore it has to be over come with "software" at a higher lever in the
    OSI model,..perhaps ever completely above the OSI model (hard to pin down
    exactly where it all has to happen at). But anyway, Windows as an OS just
    doesn't do it.

    In routers,..that is "real" routers,...not home-user/consumer boxes that are
    falsely called routers,...this would be done with Dynamic Routing Protocols
    (like IGRP). Dynamic Routing Protocols are idealy suited to do this and it
    is more or less what they do naturally anyway.

    When "home user" line technologies were invented, meaning DSL and CableTV
    Internet, they introduced new methodologies into how lines work. These
    "home-user" boxes,...and even now some of the middle-range devices (like the
    $400-$500 boxes from Cisco, Sonicwall, Watchgaurd) have the ability to do
    this wilt two lines that are not even from the same ISP. IT is done with
    some proprietary or semi-proprietary methods that do not involve Dynamic
    Routing Protocols. Some companies may even be producing high-end Firewall
    appliances that do this as well.

    However because the two lines are seen on the Internet by two different IP#s
    it only works outbound as far as I know. But the commercial lines (like
    T1s) this can be done in both directions because the Destination via both
    "paths" is identified by the same IP# and the Dynamic Routing Protocols make
    it all happen.


    --
    Phillip Windell
    www.wandtv.com

    The views expressed, are my own and not those of my employer, or Microsoft,
    or anyone else associated with me, including my cats.
    -----------------------------------------------------
     
    Phillip Windell, May 29, 2008
    #8
  9. Julien

    Julien Guest

  10. Julien

    Julien Guest

    Oh and by the way, you were talking about "software" at a higher lever in the
    OSI model ... do you have exemple of such soft that permits to do load
    balancing on multiple NICs ?

    Thx.
     
    Julien, May 30, 2008
    #10
  11. Well?,...then just do it. I'm not going to claim or even attempt to know
    every secret little thing that someone somewhere out in internet land
    figured out and wrote it in some article that I probably would never know
    about unless someone told me it was there.

    However if this was a very successful way of doing it than it probably would
    be shouted from the mountain top and everyone would know about it. Since my
    contacts at MS have never mentioned it to me,..and we've been in plenty of
    conversation where they could have,...I am sceptical of how well it would
    work. This article give really no details about how it behaves and under
    what conditions, so I suspect there are plenty of "gottcha's" just waiting
    to bite you.

    I'll have to pass the link along to my friends at MS and see what they say
    about it.

    --
    Phillip Windell
    www.wandtv.com

    The views expressed, are my own and not those of my employer, or Microsoft,
    or anyone else associated with me, including my cats.
    -----------------------------------------------------
     
    Phillip Windell, May 30, 2008
    #11
  12. It is called Nic Teaming and only works with Nics (and Drivers) that are
    designed to do that. It runs two nics against the same connection (not two
    different connections) so it will not let you use two ISPs that way you want
    to. You can use it with a single connection to a single ISP.

    --
    Phillip Windell
    www.wandtv.com

    The views expressed, are my own and not those of my employer, or Microsoft,
    or anyone else associated with me, including my cats.
    -----------------------------------------------------
     
    Phillip Windell, May 30, 2008
    #12
  13. Julien

    Julien Guest

    Actually I think you're right, I dig a litlle deeper and it seems that the
    key in the registry they're talking about only affects the answers to Netbios
    name request ... so yes it could do load balancing, but only in a pure
    windows context and if links are on the same network.

    See the following for more details :

    http://technet2.microsoft.com/windo...8024-447b-873f-6eb35d79f9531033.mspx?mfr=true

    But actually i'll be glad to have the answer of your microsoft's contact on
    the subject ...

    Thx again.

    Julien.
     
    Julien, May 30, 2008
    #13
  14. He said it does not work with MS's Firewall product, ISA Server (he's on the
    ISA Server team). But he didn't say anything about it in a generic sense. I
    prodded him a little more, but if he doesn't have much else about it there
    is one or two others outside of (but close to) MS that I can ask.

    --
    Phillip Windell
    www.wandtv.com

    The views expressed, are my own and not those of my employer, or Microsoft,
    or anyone else associated with me, including my cats.
    -----------------------------------------------------
     
    Phillip Windell, May 30, 2008
    #14
  15. Julien

    Julien Guest

    Ok, interesting ... Im waiting for the answers of your other sources.

    Thx.

    Julien.
     
    Julien, May 30, 2008
    #15
  16. Here's his quote from the second reply he sent to me. I have not looked at
    the KB articles he mentioned yet.

    ----------------
    The net effect of it is during ARP, the system will respond with a random IP
    associated with the machine.

    It's a "poor-man's" LB technique that is really far less functional than
    even RR DNS; much less NLB.

    Check out MSKB 131736, 161425, 314053.
    ------------------


    --
    Phillip Windell
    www.wandtv.com

    The views expressed, are my own and not those of my employer, or Microsoft,
    or anyone else associated with me, including my cats.
     
    Phillip Windell, May 30, 2008
    #16
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