Monthly Archives: March 2009

Why the kernel hrtimer might not be a high-resolution timer

I commented in this post that just because DAHDI thinks it has a High Resolution timer from the kernel, this might not actually be the case. When you compile the DAHDI dummy driver it checks your kernel headers to see if you compiled your kernel with CONFIG_HIGH_RES_TIMERS, in which case the specific functions in the [...]
Posted in Virtualisation, VoIP | Tagged , , | 1 Comment

Automated batch reboot of HP ProCurve switches via telnet

Today I had occasion to reboot about 20 ProCurve 3500yl switches, thanks to yet another firmware bug. The simplest way of doing this is with the “reload” command issued via telnet. Rather than logging into each switch and issuing the reload command by hand I threw together an Expect script which automatically logs into the [...]
Posted in Systems Administration | Tagged , | 3 Comments

DAHDI (formerly Zaptel) Dummy and VMware ESXi

First, some background: We run a number of production VoIP PBXs, a number of which are Asterisk-based. Historically one of the tricky things about pure-VoIP Asterisk deployments (those which talk pure SIP and IAX2) is that you still need a timing source if you want to do any conferencing, audio-playback or IAX2 trunking. Asterisk doesn’t [...]
Posted in Virtualisation, VoIP | Tagged , , , , , , | 3 Comments