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Complex Network Design Tools? 33

I'm-Not-A-BOFH asks: "How do you do your large scale network design? I am currently designing a large enterprise network - and there is a ton of information to track and think about. I use AutoCAD, Visio and Cisco Configmaker (which sucks) and many other applications. I am looking for software specifically designed to help you design a network. What tools do you use - and what tools are out there that maybe are little known? How do you begin to manage network documentation when your hosts get into the thousands and your routers and routes into the hundreds? I am really just interested in the tools used to accomplish this - as all the tools I have been finding are just not adequate or well thought out. Please let me know what you think is invaluable to you when you design your systems."
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Complex Network Design Tools?

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  • Some useful tools. (Score:4, Informative)

    by Mordant ( 138460 ) on Wednesday July 02, 2003 @09:03PM (#6354954)

    The whiteboard.

    A good knowledge of networking protocols, etc.

    The hardcore network engineer doesn't need diagrams - sh ip route, sh ip bgp, sh ip ospf, sh cdp neigh, sh arp, sh cam dyn, etc. (in Cisco-speak; there are equivalents for other vendors) are enough to visualize/plan/troubleshoot, quite frankly.
    • by RabidMonkey ( 30447 ) <canadaboy AT gmail DOT com> on Wednesday July 02, 2003 @10:45PM (#6355440) Homepage
      Yes... because a hardcore network engineer can visualize hundreds of routers/switches, all their varioius routing protocols and associated foibles, all the redundancies etc ...

      Thats assinine. Have you ever worked on a network with THOUSANDS of devices before? He didn't say 'Small Business' he said 'enterprise'.

      stupid arrogant people assuming the people who need diagrams aren't good enough. Glad you can sit and boost your ego that way, but when that stops working for you, join the real world.

      To keep this slighly on topic, try using Ciscoworks [] ... its good for planning, config backup, management, etc.

      • by Mordant ( 138460 ) on Thursday July 03, 2003 @01:39AM (#6356196)
        I do just that, every day - on a VERY large enterprise network. Before that, for an ISP hosting one of the busiest Web sites in the world.

        Our network changes so much (because it's so large, and there are many people doing things to it 24/7 worldwide) that any sort of diagrams are pretty much obsolete the moment they're drawn. The pretty pictures are useful props for talking to management, etc., but they are of zero value in troubleshooting the network.

        I don't need to visualize thousands (we went into five figures years ago) of devices simultaneously - nobody does. But since we adhere to sound architectural principles, and know what we're doing, I can troubleshoot any portion of said network without any diagrams other than the ones in my head as I poke around and a few quick sketches I might draw 'live' on a pad as I make inferences from my observations.
        • OK so for the moment I'll ignore the inadequacies of maintaining a large network without diagrams. Myself, I'm a visual person, so a diagram helps me visualize traffic flows etc. It's also useful for having a conversation with someone else about the network. But what do you do when (if) you bring in a consultant or a sales engineer, or if you hire someone new in your department? Do you just tell them to go nuts on your routers looking at routing tables, link state databases, and bgp tables? Myself, there's
          • That's untrue.

            The reason is because we're understaffed, and we're just too damned swamped to have a dedicated doc-monkey or two to do the work.

            I'm not worried about my job security - I'm one of the best in the world at what I do. When someone new joins our group, we spend 4-8 hours initially on the whiteboard, and then subsequent time as events warrant. Since we haven't acquired any new members in the last year or so, it hasn't been necessary.
            • Hey man if it works for you than knock yourself out. Myself, it seems to me that the fact that multiple people are making changes to the network 24/7 should make documentation that much more necessary, be it a visual diagram or some other form.

              I'm going to hazard a guess that even in your environment there's still a spreadsheet or a databse or something you use to look up IP's by location and make sure you don't assign overlapping IP's right? If that's the case, and you haven't played with it yourself yet,

              • For that sort of thing, we have a very sophisticated system . . . we trend SNMP stuff, use NetFlow, have RMON probes, manage both IPv4 and IPv6 address space, etc.

                We just don't have lots of pretty diagrams lying around. ;>
      • From what I have seen of CiscoWorks, it is more of a management tool and less of a design tool.
    • Maybe the hardcore engineer doesn't need it, but the company does!

      If you have a serious network then that information is too vital (to the company) to be stored in the head of one person.

      What if he/she retires? What if something bad happens? Do you get a whiteboard and start from scratch to figure out how these wires are supposed to be connected and why?

  • Netviz (Score:2, Interesting)

    by ryanmoffett ( 265601 )
    We use Netviz. It is data-driven and all the data for the diagrams can be stored in a database. Create one instance of a router, and that instance can appear in any of your diagrams with all of the properties, links and any number of user-defined attributes. Diagrams can be constructed in a hierarchy with drill-down-to-detail capability. Obviously, this is only one component of many you will need in the design process. It doesn't contain all the device specific config-checking tools that some othe
    • I agree with the above post -- the most important thing about netvis is the layers of views. On a large scale network -- at the top level -- you would probably just see your 20 or 30 buildings. You can then click on that building to see the rooms inside it, you can than click on a room to find the hardware inside it which can be abstracted into groups like "routers", "servers" or anything else you can think of. NetVis lets you logically organize your large structure and is searchable.

      You need to be abs
  • opnet (Score:4, Informative)

    by austad ( 22163 ) on Wednesday July 02, 2003 @10:45PM (#6355444) Homepage
    Opnet []

    I've been looking at this recently to see how different things will affect my network, since I can't really test them on the live network without making a lot of people and clients really mad. I have not used it yet though.

    I prefer to design the network simply using Visio to get a good logical design, and then once that is down, I create another map with the physical layout. Worry about your routing protocols after you have figured out the best logical design (redundancy, required link speeds, etc.). Most network admins have a favorite routing protocol, which for most seems to be EIGRP with cisco equipment. I personally like OSPF because it offers enormous flexibility, and it works with equipment from vendors other than Cisco.

    There's a fine line between an ingeniously designed network and something that is overly complex. It takes experience to figure out where that line is. If it seems like you are doing something screwed up, you probably are.
  • by xanthan ( 83225 ) on Wednesday July 02, 2003 @11:44PM (#6355681)
    For something that complex, no single tool will do it for you. That said, consider doing your documents in layers. Having a single document that includes all of the gory details of such a large network will be useless. Instead, do a document that describes the high level architecture, then open up each cloud into another document and describe the network topology there, then open up those clouds into documents that get into individual host level information. It is the only reliable way to grow the diagram as necessary and make it possible for others to understand what is going on at a glance.
  • by innosent ( 618233 ) <> on Thursday July 03, 2003 @12:09AM (#6355805)
    I generally use Visio for this sort of thing, but planning out a large network using an automated software tool is impossible, at least in my experience. If you can logically group your network at some level, you will find that it will make planning, and/or diagramming your network much easier. Even the largest networks are broken down into several groups at some level, and you have to keep those groups in mind. You should know the usage patterns of these groups, how much bandwidth each group needs, and where they connect to, etc. Logically map out the best performance scenario for these groups. Then start with your smallest groups, and find similarities to form larger groups, until you have encompassed the entire network. I'm assuming that there are probably departmental connections needed, as well as outside connections, but the key is how much each group of people use each resource available.
    Many "well-planned" networks fail because they aimed to provide all resources evenly, but in the real-world, this is not the case. Most of the time, a certain group of people use specific resources, and use very little of other resources. Also keep in mind that you must be able to adapt if the resource requirements for a group change, because it will happen. It's the same thing as trying to use a database wizard to optimize your database. A computer just can't do that for you. The software doesn't have all the necessary input parameters to the problem, and even if it did, the problem is NP Hard. So, in reality, it doesn't matter what tool you use to diagram the network, but actual design still has to be done by human insight, or at least a well-trained monkey...
  • how do you get to the level of designing an enterprise network without already having the experience and the toolkit to accomplish your tasks? it seems you already have the tools that most people use to design networks. i have only used visio myself for no more than a network that supports 300 users (law firm) and for a community college computer lab with a mixed platform, with vlans for experimental router subnets for cisco classes and for teaching advanced system adminstration and programming on linux.
  • by dago ( 25724 ) on Thursday July 03, 2003 @02:11AM (#6356292)
    If you want to make design, why head to cisco configmaker instead of cisco network designer [] ?
  • ..nothing too complex.

    As an ex-3Com employee, the network guys made extensive use of a whiteboard, followed by documenting what they'd done in Visio.

    I doubt you'll get all information into one form of documentation; you'll most likely need various 'parts' of documentation.
    This implies different tools for the job.

    Surely a "real" engineer can pull all this together without the need for specific tools?
  • Use your HEAD (Score:2, Informative)

    by noah_fense ( 593142 )
    First, use visio to design your CORE network. This would include all your high bandwidth, long haul fibre links. Choose a routing protocol (ISIS and OSPF are what most carriers use). If you want to implement newer protocols like MPLS, you still need OSPF or ISIS to run underneath it. Your core network should be layer three only. Avoid using ATM links becuase they add an extra "layer 2.5".

    Then, off of each core router, drop gig-e links off to your layer 2/3 routers. If redundancy is a huge issue (which is p
  • Along this line of thought, is there a product out there that is a full network simulator? Meaning, can I put routers A, B, and C in my diagram, with A linked to B, and A linked to C. Router A runs BGP between these two connections. Is there software out there to where I could put a simulated load on the router, then virtually "cut" one of the links to see what would happen and how it would affect the other link? What if one of the links' latency spiked? Using BGP with two links is a pretty easy exampl
  • Visio Enterprise has many a tool set that will both allow theoretical design and actual representation of a network and it's content. The whole thing is based on a database you can build from scratch or modify following an SNMP sweep of your devices. It does a fair job at keeping things contextual and allows you to consult your devices as objects with properties, rather than simply as icons on a piece of paper. No matter what, as complexity grows you will have to give up the convenience of paper as the m
  • disclaimer: I work for a national distributor of these products, but probably not in your area If you have a budget you can go for Physical Network Inventory or Logical Network Inventory by GE Network Solutions (formerly known as Smallworld), _ us/communication/physical_logicalnetwork.jsp/ These applications are used by some big telecom companies and model the network (physically and logically) down to single ports on switches. You can also have multiple p

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