Routed IP networks can often be too smart for their own good, as the high levels of resilience built in to most routers makes it a nightmare for engineers trying to pin down problem areas. One route goes down so another takes its place and even intermittent route flapping can have a minimal impact on end users, making it impossible to troubleshoot. In this scenario, traditional SNMP network monitoring products are of no use as they only function at the Layer 2 or physical level, so can't gather routing information from managed devices.
Proudly claimed by Packet Design as the industry's first IP route analysis solution, the Route Explorer offers an impressive range of capabilities. Operating at Layer 3 allows it to analyse traffic at the logical level, so it can gather all routing information and map the flow of traffic throughout the entire network. The product is provided as a complete appliance solution, comprising a simple Supermicro 1U chassis and P4SCE motherboard, equipped with a 2.4GHz Pentium 4 and a healthy 4GB of RAM. A single 120GB Seagate IDE hard disk looks after the Linux-based OS and stores all historical data.
Installation is simple enough, and you start with a serial connection to the CLI to set up basic network parameters for remote management access. For the best analysis performance the appliance should be placed on the network backbone, preferably connected to a core router where it can communicate with all other discovered routers. It only monitors traffic and plays no part in forwarding data, so it doesn't represent a point of failure and should have virtually no negative impact on overall network performance.
The appliance supports all routing protocols including OSPF, EIGRP, IS-IS and BGP, which allows it to maintain impressively detailed maps of the network. Our only real complaint is these must be accessed using the supplied X.Windows utility which we found unsophisticated, sluggish at times, and erratic when playing back historical data. All network data is stored as topologies on the appliance and once your selection has loaded you can easily view lists of routers, links and prefixes. The map itself provides plenty of information about the routed networks and displays each domain in different colours, whilst the link status for each node is shown underneath.
There's plenty of detail on tap. For example, the links table shows all links plus their source and destination interfaces, metrics, link status and the area or autonomous system. It's here that the power of Route Explorer shines through, as the map allows you to see routing changes in real time making it a cinch to spot any route flapping. Once you've selected source and destination routers you can see the active path between them and any changes will be picked up immediately.
As all data is stored in a database on the appliance you can easily pick out specific periods and view all the routing action from the History Navigator component. The data is displayed as a simple histogram which will highlight any problems or faults and a smart feature is the ability to play back events over a selected time period. Watching the map while the recording is running allows you to see all changes occurring to routers and links, making it easy to spot any problem areas, no matter how small they may be. Event filtering can be used to refine the data on show, and the replay mode can be changed to step through a particular period for a closer examination.
There's much more to Route Explorer, as it looks an ideal assistant for planning maintenance and testing disaster recovery scenarios in complete safety. Picking source and destination routers from the map displays the current paths between them but selecting a link and taking it down shows the impact this would have on the network and how routes would be reconfigured to circumvent this. Taking a router out of action shows the effect this would have on all routes and how the network would be reconfigured, and you can also change metrics as well.
Although the hardware specification is a little feeble for the price we have no doubts that the Route Explorer is a sophisticated routing analysis solution. Note that it's designed to work in partnership with standard network management products, so you'll still need your SNMP packages in place. Even so, it's remarkably easy to implement and use, provides a wealth of real-time information about routed IP networks, and could easily become a network engineer's best friend.
Route Explorer doesn't come cheap but if you're responsible for very large routed IP networks then this could prove an invaluable tool. The X.Windows interface could be better designed but you'll be hard pushed to find a similar level of real-time routing information anywhere else.