Chris, Taylor and the list Sorry for the late reply, had a much needed holiday and did some research on the topic. I'm willing to test Taylor's suggestion using some ugly route hacking to balance traffic over the links but I need an application that I can call to get the current throughput on any link, then match this with the links known max and then working on the 95th percentile start changing routes to try and keep each link maxed at around 95%. I know this will not be easy to achieve, but if nothing else it will be a great learning experience. Another thing I stumbled upon is the TEQL scheduling algorithm, http://www.docum.org/docum.org/docs/kernel/teql.php, and it seems to do just what I need. Considering all my connections (except the 64kbps) is PPP connections I can easily use ip-down and ip-up to enslave,deslave devices from the qdisc that does the traffic. I can also easily adjust all the iptables rules from here as well to make sure the source natting is correct. I also understand that in this situation I need to turn off return path filtering in the kernel to avoid the kernel rejecting the packets as martian packets, or is this only the case when I have control over both ends of the link and do channel trunking? Another project that came up is balance, http://balance.sourceforge.net, but this is only a TCP proxy that performs round-robin loads balancing with failover. BalanceNG, the commercial version does have weighted averages and least-used paths and I don't know what else. A few commercial alternatives, one from Sangoma called Wanpipe uses the TEQL as it's backed and it only provides the fail-over and alternative configurations and monitoring IIRC. In reply to Chris, yes, South African bandwidth prices has long been a topic that brings fear into the heart of the average South African. Read more on http://www.hellkom.com.co.za, I have nothing to do with this site but they do tell it like it is... Also, all the users are already shaped behind the box so they won't know when they are using the faster links. We don't only have these two connections, we have plenty more including wireless links with seperate providers, multiple ADSL and leased line combinations. The 64kbps and 512kbps where only examples, but thanks, I appreciate your opinions on this! As usual, any comments, suggestions, even insults are welcomed and appreciated! On 4/25/05, Chris Bennett <chris@xxxxxxxxxx> wrote: > > A little googling tells me 250 ZAR ~ 42 USD. Is this correct? If so, ouch.. that's pricey. > > 3GB (assuming B in this case is BYTE) comes out to about 9kbit / second over a month, if I did my math correctly. Ouch again. > > Does the 3GB apply to the total of up and down traffic, or just down? Because you can't control traffic coming to you very well. You can try to control TCP traffic with policing, but UDP traffic does its own thing. Not to mention jokers who decide to flood the link for the hell of it. > > Given this new info, it sounds more like you shouldn't try to use the 512kbit link at all unless the 64kbit link goes down. If you do try to push "excess" traffic onto it, all that does is encourage the use of applications that will consume the entire bandwidth available. If that is really beyond your budget, it doesn't seem like something you'd want to do. Better to set the expectations at 64kbit so the users don't get the idea of tuning into Internet radio or something. In fact, if the 64kbit link does go down, it could be a good idea to police the 512kbit link down to 64kbit, just so the users don't jump for joy when the 64kbit link goes down... (keeping in mind that policing is no guarantee that you'll actually stay below 64kbit usage, especially if a lot of the traffic is UDP). > > ----- Original Message ----- > From: Kenneth Kalmer > To: Chris Bennett ; Taylor Grant > Cc: lartc > Sent: Monday, April 25, 2005 2:48 AM > Subject: Re: Spill over > > Taylor & Chris (and the list) > > The arguments behind my choice here is cost driven, the 64kbps line is a fixed monthly rate for unlimited use, the 512kbps line costs us roughly ZAR250 per 3GB of usage. This can get quite expensive as the lines in question is for a college and we all know what students do to bandwidth :) > > Taken the amount we pay every month for the 64kbps line it's more economical to over utilize the link as a primary connection than to have it lying around as a backup. South Africa and data connections don't go well in the same sentence... > > As Chris suggested, I need something that can detect when Link A is saturated and then redirect the traffic over Link B until there is available bandwidth on Link A again. The rate limit trick of Taylor might work once I get to understand the usage patterns of these students. But for at least the first 3 months I won't have proper data at my disposal. > > Thanks for your replies! > > _______________________________________________ > LARTC mailing list > LARTC@xxxxxxxxxxxxxxx > http://mailman.ds9a.nl/cgi-bin/mailman/listinfo/lartc > > > -- Kenneth Kalmer kenneth.kalmer@xxxxxxxxx http://opensourcery.blogspot.com _______________________________________________ LARTC mailing list LARTC@xxxxxxxxxxxxxxx http://mailman.ds9a.nl/cgi-bin/mailman/listinfo/lartc
