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Channelized DS3 with Linux?
minion asks: "We've been struggling to find a channelized DS3 card for Linux that is a standard PCI format (not CompactPCI, mPCI, etc). I find it hard to believe others out there don't want the same, as a lot of ISPs could save a lot of money this way, since Cisco routers that handle channelized DS3 *start* at $30,000! I've found this card, but that is all that I've found. It would be great to dump our current Cisco, and use it as a spare if our Linux router fails. Does anyone else have some experience with this?"
This is an interesting point. A DS3 is 54 Mbps, or thereabouts, and PCI runs on a 66MHz bus, right? Wouldn't you be wasting bandwidth if you put it into a PC? I thought that was why they are putting the 100Mbps ethernet onto the Northbridge to avoid the PCI bus entirely. I have to admit to only a vague understanding, so if anyone out there knows better please chime in.
This kinda goes back to what I was saying here and here. Again, we need more information from the requestor. Driving 12Mbps out of a HSSI might not meet their needs if they are going channelized to pull a bunch of DS1s into a DS3. I can't really think a way off the top of my head to do that with a 3600+HSSI without your telco/upstream doing some fancy stuff. One way the telco could do it is term the DS3 on one of their boxes and hand the traffic back off to the customer across a point-to-point DS3 terminating on a customer 3600+HSSI router. That would take a lot of the control out of the hands of the customer and would cost the telco a bit of money. I'd imagine the cost would offset the savings of buying a 3600 with a HSSI instead of a 7x00 with PA-MC-T3.
I've agree with you that if you can't justify a one time $30k cost that you've got to think really hard about what you're doing. Maybe the original poster works in public sector where you can often get dirt cheap telco rates so the one time equipment costs look really really high compared to monthly recurring.
The more I think about this Ask Slashdot the more I want to know the driving factors behind it. Perhaps a channelized DS3 isn't the right solution for them. I really wish they'd given us some insight into their design goals with this project...