CB> Date: Tue, 8 Jan 2008 09:29:03 -0600 CB> From: Chris Blair CB> It does, thanks for the reply. When you say 70%, should we not be CB> spiking that high during business hours? All of our activity is during CB> the day, the T1's are basically empty at night, maybe some Microsoft and CB> Anti-virus updates. During the day I have seen spikes as high as 2.9 out
That's a bit high. Another rule of thumb: If WAN latency increases due to congestion, consider more bandwidth. A 1500-octet packet takes about 8 ms to transfer via T1. Say that ping times [to your ISP's router] regularly hit 40 ms. This indicates that five MTU-size packets (or equivalent) are in the queue ahead of the pings. CB> of 3.0. I am going to talk to our ISP to get more detailed reports and CB> get some averages for data in/out during business hours. Most ISPs track bandwidth as ( transfer / time ) over five-minute intervals. Note that momentary usage can be even higher than the numbers you're given. I suggest examining bandwidth use at various percentiles. You should be able to ask the ISP for raw data, then analyze accordingly. If you find something like: 95th = 90% utilization 90th = 80% utilization 80th = 70% utilization You'd definitely want more. OTOH: 95th = 99% 90th = 60% 80th = 35% would be less clear-cut, despite the higher peak. Also consider calculating percentiles during a narrowed time-of-day range... or remember that the work day is roughly 1/3 of the total day, meaning what's officially "50th percentile" may effectively become "83rd percentile during the time that it actually matters". Or simply look at things emprically: Is the connection "fast enough"? What's the cost/benefit tradeoff of "faster"? Finally, note that NxT1 is _not_ faster than single-T1 for a given stream. The highway is wider, but any given car still must obey the same speed limit. (Yes, I'm deliberately ignoring per-packet round robin techniques. That's a separate can of worms.) Eddy -- Everquick Internet - http://www.everquick.net/ A division of Brotsman & Dreger, Inc. - http://www.brotsman.com/ Bandwidth, consulting, e-commerce, hosting, and network building Phone: +1 785 865 5885 Lawrence and [inter]national Phone: +1 316 794 8922 Wichita ________________________________________________________________________ DO NOT send mail to the following addresses: [EMAIL PROTECTED] -*- [EMAIL PROTECTED] -*- [EMAIL PROTECTED] Sending mail to spambait addresses is a great way to get blocked. Ditto for broken OOO autoresponders and foolish AV software backscatter. ~ Upgrade to Next Generation Antispam/Antivirus with Ninja! ~ ~ <http://www.sunbelt-software.com/SunbeltMessagingNinja.cfm> ~
