Colin, for the record I think this post was exellent and deserves a compliment. It is probably one of the best outlines of what is needed for a professional system I have ever seen. Marnus van Niekerk Colin Anderson wrote: I concur with your approach, but "Tier 1" means as little here as it does when evaluating Internet backbone carriers. could you expand on what evaluation criteria you use? I'm going to be pre-speccing some stuff myself this month...Sorry I should have been more clear. A good Asterisk install needs a holistic approach to use a hippy dippy phrase. A Tier 1 server, which is a midrange to high end name brand server from the Big 3 (Dell, HP/Compaq, IBM, am I missing someone?) is usually highly optimized for bus bandwidth although that design was intended for a different use - usually massive disk I/O. As well, a Tier 1 server will have two seperate, independent PCI buses and this to me is a critical feature - it allows you to completely separate your TDM traffic from network, disk I/O etc. On my big production Netfinity, I took great care to ensure the Digium cards were all on their lonesome on a single bus, and everything else on the other bus. This is how I can run two TE110's in a single box with no problems. zttest does not give me 100% all the time, but on the other hand it *never* drops below 99.9987%, even under load. I selected this Netfinity because of the obvious care put into it's design, but the specs are unimpressive: quad Xeon 700's. CPU is over rated for Asterisk, IMO unless you are doing tons of transcoding and if you are doing that, then your design is flawed.Anyway, the holistic approach (to go on a small rant for the newbie lurkers) be summed up as follows: 1. Good box, see above 2. Good LAN - this is so critical and so often overlooked in the day and age of guys crimping their own cables and running $150 switches. You can't do that, and if you do, you do so at your own peril. Managed swiches, professional cable installation. This is not a problem for me since I *am* a professional cable installer but I have actually witnessed people making patch cables with a flat blade screwdriver and a hammer! 3. Tuning of the LAN - VLAN's are good. QoS packets are good. Switches that honor the QoS packets are good. 4. Handset selection - this is another biggie. I've selected Snom 360's, and yes they have warts, but they are feature rich for the price and Snom is really good about revising firmware. When you select handsets, GET YOUR USERS INVOLVED. 5. Tuning of Asterisk box itself - this cannot be under emphasized. This is a very important step and tuning methodologies vary according to distro, skill of the admin, and particular circumstances. I've learned *way* more than I ever wanted to about processor affinity sinc I started using Asterisk. 6. Termination of PSTN. Basically I would never do an Asterisk install where I was forced to do something stupid like aggregate a dozen Centrex lines or some mickey mouse deal with FXO ATA's or whatever except for a hobby or prototype install. PRI, BRI, IAX or SIP, don't mess around with anything else. 7. Relationship with provider. What is their SLA? Is it the incumbent or the clec? An incumbent will be more expensive and more difficult to deal with but they will tend to be more reliable. A clec will be cheaper and they will be way more accomodating but you will most likely not get five 9's from them. A VoIP provider should never be trusted, period. You will not get five nines from them, ever. Plan failover situations accordingly. 8. Plan plan plan plan. A good install of ANYTHING is 80% planning 20% doing it. What is your plan when your primary PSTN provider fails? What is your plan if your Asterisk box goes pear shaped? My dialplan can survive either PSTN, WAN or LAN failure (albeit with reduced functionality). I also keep a cold spare, an identically configured box that I can literally throw into the rack, turn it on, plug in the PRI's and no problem. 9. Internet bandwidth and latency. I am fortunate enough to have a great IP provider. Ask for demos - most guys will install a 90 day trial or something like that. Do not believe the brochure, get the product installed and put it under load. 10. Traffic prioritization at the IP demarc - total no brainer. 11. Constant, constant user feedback and remediation. If you are not talking to your users, your install will ultimately fail even if you have the best of everything. Underpromise and overdeliver. Never loose sight of the basics - they have to pick up the phone, and it has to work. Always. _______________________________________________ --Bandwidth and Colocation provided by Easynews.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users |
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