NetAdmin
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| reply to funchords
Re: A word on QOS and prioritization
said by funchords  :All traffic is forwarded at the speed of light. No it isn't. Not even optical components forward at the speed of light. And forwarding speed is irrelvant, as it is the capacity of the PHY (physical layer) that is what is important.
Big caps so that you know it is true: THERE IS NO SUCH THING AS PRIORITIZATION. There is only "deprioritization." I'd like to know where you found that information...
In order to allow certain packets to get ahead or cut in line, network devices slow down and fragment everything else. Raising the priority of a flow of traffic and that resulting in other flows treated having to wait due to their lower priority is vastly different than explicitly lowering the priority of one flow of traffic.
Comcast isn't very interested in proper DiffServ because it doesn't allow them to run their networks under extended congestion conditions. They're trying to avoid upgrading the network as often as they otherwise would have to. Unfortunately, there is no alternative for that problem. Comcast is treating the symptom and not the problem. Part of the problem is that Comcast and others have been pulled into the battle of the cablecos versus the telcos, resulting in insane speeds for ridiculously low prices. Providers are pricing their internet packages at points where it becomes difficult to deal with the heavy use that is becoming more normal. In the case of DOCSIS, there is no reason why it a provider should be able to offer 10+ Mbps of service to a residential user at the same price as 3Mbps several years ago. Unless they are actively splitting nodes, you still have the same amount of bandwidth now as you did a year or two or three or four, especially when you take into account that usage is rising across the board.
Providers need to start balancing out better the speed offered and the revenue they bring in so they can better maintain capacity.
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funchords
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| said by NetAdmin :I'd like to know where you found that information... I work in this industry and I've seen this code. Think about it -- write it in psuedocode -- how WOULD you give traffic priority? You wouldn't -- you can't. You can only slow everything else. It's like how a firetruck or an ambulance gets priority, everyone and everything else pulls over to let it through.
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| said by funchords : Think about it -- write it in psuedocode -- how WOULD you give traffic priority? You wouldn't -- you can't. You can only slow everything else. It's like how a firetruck or an ambulance gets priority, everyone and everything else pulls over to let it through. And prioritization is only meaningful when their is congestion. Until their is congestion there is no need for priority schemes because everything is getting thru. Only when routers start dropping packets do priority rules kick in.
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funchords
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said by NetAdmin :Part of the problem is that Comcast and others have been pulled into the battle of the cablecos versus the telcos, resulting in insane speeds for ridiculously low prices. I don't know where you get the idea that our speed is particularly fast or that our prices are low. Compared to the rest of the high-tech world, we're not doing so hot -- even though we invented this Internet thing.
That said, Comcast has been offering 6 Mbps since mid 2005. Moore's Law and Cisco's worldwide bandwidth trends both say that our speed should have doubled about every two years. It's now mid 2008 and we're looking at 6 months to a year before Comcast's next speed upgrade.
They've fallen behind.
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Robb Topolski -= funchords.com =- Hillsboro, Oregon
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NetAdmin
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| said by funchords :That said, Comcast has been offering 6 Mbps since mid 2005. Moore's Law and Cisco's worldwide bandwidth trends both say that our speed should have doubled about every two years. It's now mid 2008 and we're looking at 6 months to a year before Comcast's next speed upgrade. You misunderstand Moore's law. Moore's law doesn't apply to networking, only processing power.
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funchords
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1 edit | I do understand it, but you are correct that what I described isn't Moore's law per se, but an extrapolation...
For example, I cite the mighty uncitable Wikipedia: http://en.wikipedia.org/wiki/Moore%27s_law#Other_formulations_and_similar_laws |
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NetAdmin
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| Okay, I see where you got that from now...
While you are right that speeds should double every year based on that statement, the reality is that it doesn't hold true at the edge of the network. The applications of "Butter's Law" only really makes sense for backbone circuits. Look at ethernet for an example - it took several years for ethernet to progress from 10Mbps to 100Mbps to 1Gbps to 10Gbps. The progression from 10Gbps to 100Gbps is proving to be even slower.
While optical fiber capacities do increase at an impressive pace due to tricks like DWDM, the costs of pushing those advances to the edge of the network are problematic. That doesn't mean I don't think FTTH should be in wide deployment now, but there are other problems. Equipment is not nearly as easy to swap out in the last mile to keep up with the newest advances. And with most providers being traded on the public market, most investors (wrongfully) don't like CAPEX because it has the effect of lower short term gains.
I understand now what you are saying and in an ideal world, the network would be that flexible. Sadly, short sighted investor mentality and the idea that you only need just enough to keep up with the competition is a mainstay of the American way of doing business.
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funchords
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| said by NetAdmin : Sadly, short sighted investor mentality and the idea that you only need just enough to keep up with the competition is a mainstay of the American way of doing business. NOW ON THIS POINT YOU AND I COMPLETELY AGREE.
Instead of quarterly reports, can we ask the regulators to roll the dice and make reports on an irregular interval with an average of 5 reports every 3 years?
The current regime of trying to make expectations each quarter really threatens any long-term vision.
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