Day 2 at the Trixbox seminar in Boston…not that I’ve learned a whole lot of new things, but we are all finding that our prejudices are confirmed. Yesterday we spent much of the morning installing the VMWare version of Trixbox and connecting a couple of SIP end points. We have the X-Lite softphone connected to a Polycom desk set. My seat partner is David Mandelstam of Sanoma, one of the sponsors at the conference. We’re having a terrific troubleshooting session by Mike Joyce of Fonality. Lots of tidbits/opinions and debate. For example:

Mike Joyce of Fonality

Sizing the machine adequately.

The load is especially heavy with software echo cancellation
Use hardware echo cancellation

AppConference will be added for conferencing….and will be an alternative or replace MeetMe.

Recording — Recordall – is really a bottleneck. DiskIO is the issue, and you need a quad Opteron, huge disks, etc.

“Bus Bubbles” interrupt conflicts.

PatLoopBack – Zaptel repository

Ethernet Card Considerations
Cache optimization
9 out of 10 on-board Ethernets on motherboards are good

Rhine Chipsets
Intel Ethernet Express is not good for VoIP
For cable modem and DSL setups (Motorola Surfboard…etc)

The routing equipment at the CPE that has packet optimization that sucks on cable modems. You can’t see more than a couple concurrent calls on a typical cable or DSL connections. Not a problem with the carrier, but the problem at the CPE….the DSLAMS are OK,

Problem is shared cache for inbound and outbound
The cheap modems can’t do context switching enough between the two to support more than a couple of calls.

Under 50 concurrent calls is where Asterisk has a sweet spot..with all the features of a more expensive system. Asterisk doesn’t scale up higher (easily), the big guys don’t scale down (easily).

Using VoIP on the Internet
Limitations of Broadband Connections
Ping 20 millseconds at As you lower the interval, you have
ping -c 0.02 -c500

Need to see 0 packet loss.

Place in the DMZ setup sometimes…and make sure that the DMZ is located

SIP compatible routers don’t work unless it is under $1000 dollars. Finality

Linksys BEFSR81 – DMZ host.
PFSense – OpenBSD – Live installation, etc.
IPFW

People try to overcomplicate things.

NAT issues – Don’t install the phones and the PBX on different NATs.

InGate – Sipperator — Sip Proxy Session Boarder Controller

Aeronaut 1050G
Astra 480Et (?) wifi phone

Fonality: The vast majority of problems are related to networking.

Don’t ever ever ever sell a system without RAID
Software raid is better than hardware
Don’t use RAID 5 for a Linux or Asterisk
80 gig drives work fine.
Never been able to justify the cost of SCSI disks
Rebuilding a RAID 1 drive takes about 10 minutes.
Hot swapping
They have to be able to fix things over the network. All PBXtra stuff is supported remotely.

MDADM man
SATA RAID at the install Disk DRUID, etc.
there is also a setup RAID.
Swap needs to go on both disks.

For 50 bucks a month offer back up service with a chron job, and ftp the data to a NAS at a co-lo.

AGIs are super easy to write.
If you don’t have friends who write perl, get some.
Call Files – Click-to-Call, Ticketing Systems, CRM systems
split() on csv for easy archiving Tie the call records into a CRM system. How much does it cost you to convert a prospect to a customer.
If you go into the operations side a company, you’ll have an easier time, rather than go into the IT side a company.