Time Warner Cable Implements Packet Shaping? > What is "Packet Shaping?"

What is "Packet Shaping?"

They choose to degrade and lose most incoming/outgoing packets that they recognize as Torrent (even encrypted), P2P programs, newsgroup, FTP,VOIP etc, so that the speed is artifically limited to generally dialup speeds, if they're hamfisted like my ISP. Anything can be targetted. If one P2P program is running on the network, then *all* packets are degraded, doesn't matter if you're surfing a web page at the same time, they slow you down.

The nice way to do this is to throttle everything instedad of throttling selectively. Otherwise, why don't they advertise that they only guarantee just HTTP protocol? HTTP is not just the internet anymore...

Thanks - especially for explaining it in clear English.

reply to jyc76

Gotta second you on this, jester121. Either Rogers is doing something incorrectly or jyc76 is misinformed. Where I work, we dedicate a set amount of bandwidth for shaped traffic. Let's pretend that's 600Mbps. If you're the only bandwidth hog that's doing P2P or ISO downloading (or whatever else) at any given time, you have full access to the 600Mbps, up to the limit of your service level (whatever level you're paying for). Now, say there are 600 bandwidth hogs competing with you. Assuming each one is downloading at full blast, and pretending there aren't other factors such as overhead to consider, each one of you should theoretically achieve 1Mbps.

It's also important to note that as each packet comes through our WAN links, it gets classified and if it matches certain criteria (P2P, etc), it is assigned to the hog pool. Non-hog traffic is routed through the network normally.

So, if you're using a program that fits in the hog criteria, your traffic gets delayed while you wait for your piece of the imaginary 600Mbps hog pie. We've seen in the past where high priority traffic (Ventrillo VoIP traffic to be exact) was really screwed up by accidentally classifying it as hog traffic. Ventrillo packets were being delayed while the user waited for his / her turn at the 600Mbps, and subsequently the voice traffic got to them with significant jitter. It was an unfortunate situation, and it really helped drive home the importance of knowing which types of traffic to shape.

One last important thing to know -- broadband ISP's limit the maximum number of simultaneous connections you can have open at any given time, unlike a dedicated circuit such as a T1 or commercial fiber line. If you're being capped at only 50 open connections at a time, it's highly unlikely that your P2P will perform as well as someone that can do 500 simultaneous connections, regardless of how big your slice of the hog pie is. ISP's do flow limiting to cut down on their equipment load. This practice can make the difference between having a costly network component die after one year of service instead of five.

I hope my little rant helps clear up some confusion. Presumably other networks do their shaping in the same way, but your mileage may vary. More than anything, I wish companies would just be up front about how they manage their networks. In my opinion they are completely justified to run things as they see fit, but being open and forthcoming could make all the difference in the world between having a pissed off customer and one who happily understands how his or her connection should behave.

- Tate

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Happiness is an OC-48 in your basement...

I understand the benifits of packet shaping, what I dont understand is why they would reserve the right to shape VoIP traffic. The average VoIP call uses 90k, how is that negatively impacting the network??

I couldn't say. I know we assign VoIP one of the highest QoS priorities on our network, and I can't imagine why any other ISP wouldn't do the same. I could be a pessimist and say they might do it to encourage you to use their VoIP services instead, but I'd rather give them the benefit of the doubt and assume that the statement was issued by marketing / PR suits instead of any division of the company that actually deals with technical details. There's no way to know for sure unless they either clarify their intentions or actually start to shape VoIP traffic.

- Tate

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Happiness is an OC-48 in your basement...

reply to Cogdis
Once again, for the cheap seats:

Traffic shaping doesn't automatically mean make it slower.

It just means treat it differently. If my ISP would identify and tag SIP traffic (for example) while it's on their network, that would be great, I'd really appreciate it.