back to article VMware, Cisco stretch virtual LANs across the heavens

VMware and Cisco have teamed up with a quartet of fellow industry heavyweights to attack a vexing virtual-network configuration problem by proposing a solution that takes its inspiration from – of all places – cell phones. VMware has long since figured out how to teleport virtual machines around a network of servers using its …


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  1. kosh


    So it's a tunnel with an access list.

    Seriously, guys, please stop reinventing the wheel just because you don't know how to use dynamic routing protocols.

    I'm looking at you especially VMware. Your complicit partner Cisco should damn well know better.

    1. Anonymous Coward
      Thumb Up

      emperor's new clothes (as always)

      Cisco should indeed know better but it's striving to be relevant in the clouds, just like everyone else. Hooray for marketing.

    2. mikie


      yes and no. The point of this (and it sounds like it involves LISP) is that you shouldn't have to change the IGP database or cause any churn of your routing protocol to move a host around your network when you can just tunnel then shift the traffic to the host address.

      The big change is that for years we have been told that tunnels are not the way but now it seems they are :)

      1. kosh

        and next...

        Soon enough you need a distributed protocol for managing your tunnels. And no doubt that tunnel creates a FIB entry and an adjacency table entry. Thus reinventing the IGP.

        It's so easy to advertise a host route, so why not just do that?

  2. Anonymous Coward
    Anonymous Coward

    The circle is complete

    First we came off the gold standard leaving us with a fiat currency

    Then came virtual money,

    Now in various fields we have tech companies selling us virtual products.

    The circle will be complete when employees pretend to work and employers pretend to pay them

  3. Anonymous Coward

    Their head is so far in the clouds

    they seem to have forgotten about security. How easy is it to hop between DMZ's now :)

    1. Kirbini

      Good question...

      The DMZ hopping problem is particular troubling for me in attaching physical machines from different DMZs to the same SAN. However I think virtualization, especially within a good cloud, helps to eliminate this problem, even in flat network designs. Think of this: your physical hosts/node machines are connected to the private management net, the SAN net and the public net. If anyone could get access to the host machine then all sorts of nefariousness is possible. But the host itself doesn't have an IP on the public side and the SAN/management side is protected by your firewall. From the VM perspective, there is only one network connection and it's to the public network. Even though the VM is attached to the private SAN and you can console into the VM from the management side, the VM only knows about the public side and can't move data through the private interfaces. Since the danger comes from the public side, the risk is safely mitigated.

      Or not. I must admit coming to this revelation while I was falling asleep last night so it may be suspect. I look forward to any corrections smarter people may have.

  4. Adrian Lewis


    Kosh: I'm guessing you haven't actually read the specification then. Less tunnelling and more encapsulation and while the concept is very simple it does solve a big problem very cheaply, efficiently and intelligently. Dynamic routing just doesn't do what this is intended to do unless you have a lot of physical interfaces and plenty of memory for VRFs = unnecessary complexity. Oh but there's MPLS/VPLS - similar yes but I can reap all the benefits of VXLANs even using a basic Netgear/D-Link/cheap switch (not that I would but I could).

    1. kosh


      Not only have I read the specification but by referring to it as "tunneling" I am quoting it. You can't split the difference between tunnels and encapsulation; the latter is simply the wire format of the former concept.

      The truth of the matter is, a man was once faced with problem. A network that wasn't quite numbered how he liked it for a clean topological separation. "I know," he said, "I'll use a dynamic mesh of self-discovering tunnels". Now he had two problems.

  5. Adrian Lewis

    hop between DMZ's?

    About as easy as compromising the hypervisor - no change there.

  6. Anonymous Coward

    Asking for trouble...

    VMware have been purveyors of braindead networking "protocols" for years and it's no surprise they're still at it.

    The shocker is Cisco being so desperate to get back with the cool kids it is throwing away the whole "How to design large networks that don't suck" rulebook and actively encouraging poor practices.

    Spanning Layer2 networks accross multiple sites is a cardinal sin FOR GOOD REASON - now instead of a broadcast storm, or multicast flood ruining the day for a single location the whole global network is at risk...

    Long before that there will be un-expected behaviors showing up when LAN protocols start experiencing WAN latencies and performance issues when WAN links give up trying to be LAN links.

    1. Kirbini
      Thumb Up

      Nail, hammer, smack on the head...

      Alas I have but one thumbs-up to give. You deserve more.

    2. Anonymous Coward

      Room 101


      Spanning tree should have been killed years ago - but it helped sell switch ports because STP keeps turning off and stopping yopu using redundant links...

      Most of my clients want to get rid of STP to improve throughput and decrease latency.

      Sometimes "tried and tested" is not enough and this is what drives innovation.

      I'd learn the new stuff if I were you...

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