How to increase outbound call capacity with multiple DSL lines
Submitted by kimkhan on Wed, 08/27/2008 - 8:41pm.
Hi,
Currently I am limited to 5 simultaneous outbound calls with our single DSL provider's upload bandwitdth of 512Kb (I want to use the g711) 711 takes about 85Kb.
I want to increase this capacity to 10 simultenous calls by adding another DSL line.
I have looked at following two load balancers: (Peplink is VOIP Sip optimized)
PEPLINk: http://www.peplink.com/products/balance-200-300/
TP-LINK: http://www.tp-link.com/products/product_des.asp?id=14
I have also looked at the following Open source ones:
smoothwall, pf-sense, IPCOP, etc.
I am sure there may be many out there that have added multiple DSL/Cable providers to increase their call out capacity so I would like to know the best recommended practice to do this. And if there are any inherent problems with registering with the ITSP (VOIP Provider) etc. since there are two IP addresses from two DSL providers and calls may go out using any of the two.
I have the leverage to change my VOIP service provider (ITSP). So if there is something I should be looking at the Provider end to support this.
If it is not achievable at all then I would like to know if I can use multiple trunks to go out on multiple DSL lines and limit each trunk to 5 channels and when all the channels in that trunk is used up then use the outbound routing sequence to start using the next trunk on the list.
Any suggestions, recommendations and ideas would be great appreciated including recommendations on hardware options as well.
( I can't afford the T1 Line yet, maybe in the future but not yet)
Thanks,
Kim
Product suggestion
Thu, 08/28/2008 - 12:09pm
Check out Elfiq's products (www.elfiq.com), they also have a page on VoIP. The 550 model should be fine for what you want to do.
If you're using SIP to connect to your ITSP, make sure the product you get supports protocol persistence / stickyness. If the product cannot enforce a session onto one link and keep it on the said link, you won't be able to talk much since the connections will be dropped constantly.
Have you checked on SDSL?
Thu, 08/28/2008 - 1:13pm
Sorry this doesn't directly address your question... but it's another angle you might consider.
Based on your upload speed, I'm guessing you have ADSL service from your provider which is optimized for Internet browsing. You might try calling them to see if you can upgrade to SDSL. You may have to go thru a customer support tech or two to get someone that knows about it or you might have to end up in the business office, but they should offer it. While more expensive than ADSL and typically tariffed as a business service, the upline and downline speeds are the same so it is more like a T1 without the cost of a full T1. Maybe you'll get lucky with the pricing/availability and you can avoid hacking together a hardware/software solution.
Also hard to find but still available may be a fractional T1. You could probably buy it for about $20 per channel per month. Then use it as your primary connection and keep the ITSP as a backup trunk.
Jason
This post is all over the
Thu, 08/28/2008 - 1:58pm
This post is all over the place and non-edited.. I'm just writing ideas down as I think of them.
you could always trunk your dsl lines if the isp supports trunking. Also, look into experimenting with other codecs. I know you don't want to, but don't rule it out.
There's always the IT Admin's credo.. pick the users you hate the most and set their trunks for the lower bandwidth codec.. (hehe). and people you find attractive should get better service :)
Just kidding.. or am I? *mischievous grin*
Seriously though, there are other ways to do this. Set up the second dsl line in your network with a separate gateway, stick a SIP proxy there in between the trixbox and send some of the calls out the other gateway (dsl).
Cheap and effective. Also.. look into symmetric dsl as well.. you may not get as much downstream, but that's not what you're after.
In some areas where cable modem access is available, you can get a cable modem from your home (as long as you're in the same county) and just bring it to work and plug it in giving you the higher speed of a home-based cable modem (with something like optimum boost) as long as the cable company is the same @ work and @ home.
Cable Modems basically tftp their configurations from a centralized server that sets class of service, etc.. This works, because entire regions usually share the same tftp server, etc. As long as internal network connectivity is there (on their backbone), it usually works.
For example, if I took a cable modem from a home user in brooklyn and brought it to manhattan and just hooked up the cable, as long as it's the same provider, I would get the cheaper rate. Now, keep in mind this is against the Terms of Service, but then again, what they charge for "business class" service is a crime considering there's no QoS on a head-end segment anyway. I don't condone it, just pointing out weaknesses in Cable Modems Technology.
Also.. If you're in an office building, check to see if any other companies in your building would consider sharing a T-1 with you.. or if a company in your building has some excess capacity they'd be willing to "sell" you. Then, it's just the cost of an ethernet drop between your offices.
There's more than one way to skin a cat..
Cheers.
Quote:
Cable Modems
Thu, 08/28/2008 - 9:19pm
Quote:
Cable Modems basically tftp their configurations from a centralized server that sets class of service, etc.. This works, because entire regions usually share the same tftp server, etc. As long as internal network connectivity is there (on their backbone), it usually works.
Cable modems are layer 2 devices using DOCSIS standard, tftp is a layer 3 protocol. Cable modems provision based on the mac address.
This is why the cable company hates to bring coax into an office building.
Quote:
for "business class" service is a crime considering there's no QoS on a head-end segment anyway. I don't condone it, just pointing out weaknesses in Cable Modems Technology.
That's not universally true and not a fair treatment of 'business class' cable service. Our ISP is peered with Time Warner cable in the Cleveland and Akron area. TWC Biz Class customers are provisioned with a higher priority that home subscribers. They are also given access to the peer paths (like us) on the MPLS backbone. Home users must egress the common gateway. This makes a huge difference. The second difference for the price is the SLA (Serviec Level Agreement) home service is best effort, biz class has SLA terms for repair time and data rate availability.
--
Scott
aka "Skyking"
Member Since:
2007-03-07