John Stumbles' Work page

What I do

Until spring 2002 I worked at BlueArc (a company developing a new generation of network file servers) where I was a senior validation engineer (i.e. I tested things).

During March 2001 I worked at PruTech, the technology side of the Prudential insurance company, managing their network. This job ended abruptly (it's a long story :-()

Before that I worked at the I.T. Services Centre of the University of Reading, where I was officially called a Computer Programmer.

I have hacked around in a variety of programming languages though I trained in Electrical and Electronic Engineering (at University College Wales, Swansea) so long ago that, after a mandatory Fortran course in the first year, I wasn't allowed near the computers afterwards! Since then I've progressed(?) from analogue through digital electronics, to computer networking, and from cabling, connectors, interface circuits: RS232 etc., through to X.25, IP, TCP/IP, PC-NFS, SNMP, H.323 ... etc)

I was here since 1994, during which time I learned more than I really wanted to know about configuring PCs through setting up PC-NFS on users' PCs (and showing them how to use email etc., and dealing with "it was OK before you touched it" type problems). During that period I wrote a lot of DOS .BATch files to speed up the installation and configuration process, and some utilities to supplement existing freeware and DOS utilities. (If I'd known then what I know know, however, I'd have done it in Perl!)

I tended to call myself a Network Manager as my job was mostly managing the network (natch :-))

When I started at the University the idea was that I should get the Netcomm NMS3000 (which they'd bought before I arrived) working. This was a sort of me-too HPOV-type node monitor with discovery, MIB-variable monitoring and alarms/alerting etc. and it ran (like cold molasses :-) on a SPARCstation 1.

Apart from the (lack of) speed, I could never quite get my brain round how it monitored MIB variables and its alert mechanism, and found its habit of reporting as an alert the disappearance of any host which it had ever discovered (most of which were users' PCs being switched off when they went home at the end of the day) quite un-useful. Also at this time, although I had (as mentioned) learned quite a bit about DOS, I was severely unclueful about Unix, and about SNMP, and also about much to do with Ethernet and IP etc. (I like to thinks that's all different now :-).

Along the line since then I got some way up the learning curves and played with a few monitoring and management tools. Some (BTNG, Beholder, DNPAP, javasnmp, advent and some commercial packages including HPOV) I looked at but passed by, and there were some home-brew tools we used to use but no longer do: one checked parts of the network by pinging groups of hosts known (from more-or-less hand-generated lists) to be in one area so that if none responded one could surmise that there might be a network problem (this was when we had practically no managed devices besides our core routers). Another tool used an snmpwalk script to gather interface utilisation stats from our routers and plot graphs (as .gif images) of each one (as done by MRTG, but without the by-week and by-year, etc, plots of that tool).

By the time I left the University we had a set of tools which, while by no means complete or integrated, gave us useful information:

HP Open View

We were all set on buying HPOV - at least NNM and possibly NetMetrix - a year or so ago. It's the industry standard, it's supposed to be able to do anything that's capable of being done, and it looks good on a CV! We had an eval version running on a Solaris box which I was supposed to be working on. At the same time a couple of us were going to HPOV users' group meetings, and I was on the OV users' mailing list, and what I was hearing was that setting up OV and running it were a major chore. Also, whilst it would discover networks at layer 3 it didn't seem to have the ability to map layer 2 topology, which is a major component of our network (the layer 3 map is a simple star which any of us can see in our mind's eye: the layer 2 topology is far harder to remember). Some of the things it did, such as reporting 2 or more hosts (with different MAC addresses) using the same IP address, I already had home-brewed tools to do which I saw the possibility (now realised) of extending in useful ways (e.g. to report the names of the users of the machines involved). Other Network-Management information which we wanted and found useful was more in the user domain which OV - at least the components we'd been looking at - did nothing to provide.

We were also looking for a cable management system, to keep track of connectivity at the physical level: wall ports, installed cables, patch panels etc. It seemed sensible to find something which would integrate with HPOV, sharing overlapping information so that one could correlate, say, the network identity of a host with its wall port, through the patch panel to the hub port, to the VLAN, subnet or network. We asked speakers from HP at a user group meeting, and elsewhere, but it didn't seem that this sort of integration was available.

Also we were running MeterWare, which is an application for use with RMON probes, but which has a network node discovery and monitor function built in. This gave us an NNM-like picture of our network, with icons for devices which went red when the device was down, and this gave us an at-a-glance view of the health of our network. We had started to use HP Top Tools for Hubs and Switches, which is bundled on a CD-ROM with the HP switches we were buying: this application discovers devices on the network and shows at-a-glance the worst segment on any of the HP switches in terms of utilisation, broadcasts, errors, etc. A colleague had set up MRTG which graphed medium and long-term utilisation on various segments of our network. Between these and our home-grown tools the value to be gained from OV seemed not to be worth the effort - not to mention cost - involved.