Category Archives: Information Technology

Decoding TCAP in Wireshark

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Just jotting this down as a quick note, as I had some problems getting Wireshark (not it’s fault) to decode a SIGTRAN trace I was working on.

Normally you have to configure TCAP to know what Subsystem Numbers [SSN] to handle on the SCCP layer e.g. 7 for VLR, 8 for MSC, etc. and this is done under Edit -> Preferences -> Protocols -> TCAP

TCAP SSN Config

Unfortunately my trace had a bug – there was no SSN in the response message so Wireshark was only decoding up to the SCCP layer.

SSN Not Present

You can handle this case by instructing SCCP to decode as TCAP by default.

SCCP Default Payload

Internet Access in Awkward Places

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Finally got around to putting up a description of a project I’ve been poking along for a while to put Internet access and a remotely accessible security camera in the parents holiday home (ld building, thick walls and no wireline connectivity) – all the hardware used and details on the build are available here.

Link

An EMC systems engineer has written a blog post about the VMAX FAST VP array. While it’s full of good advice, he unintentionally sums up everything that’s wrong with many applications in IT today: the knobs.

This is a problem I’ve seem more then once – the box has many nerd-knobs and therefore people feel they have to fiddle with them. Once they start to do that, inevitably something goes wrong and the performance drops. Then they start to fiddle some more to try and ‘fix’ it, until there are so many knobs turned it is impossible to maintain/troubleshoot.