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What is the problem with DPI? It slows down torrent downloads, which are already slow, but speeds up more synchronous activity like web browsing and chatting.

by pj 18y ago

What is the problem with DPI? It slows down torrent downloads, which are already slow, but speeds up more synchronous activity like web browsing and chatting. Don't we all want that?

Kejistan 18y ago
DPI does not specifically slow down bittorrent traffic or speed up http traffic. DPI filters traffic based on the data in the packet, which affects all traffic. What happens to that traffic is up to the person implementing the DPI. The problem with DPI is that its akin to the post office reading all of your mail.
- pj 18y ago
  The post office has a similar system, except they charge customers differently to get information to the recipient faster. Overnight costs more than first class for example. If DPI were used to allow customers to pay based on priority, would that be acceptable? For example, if you only want to pay 1 cent per GB for a torrent download that gets packets to you at 1/3 the rate of HTTP packets, which cost 2 cents per GB, would something like that work? I am not proposing it, just continuing the post office analogy.
  - Kejistan 18y ago
    I've never understood this analogy. We already pay more for more bandwidth which is supposed to allow us to receive packets faster. This always sounds like they're expecting me to pay twice for service.
silentOpen 18y ago
Those protocol discrimination and QoS concerns are possible results of "deep packet inspection" (how deep?) but just because these results are good does not mean we should accept DPI (~converse fallacy). The article outlines some of the problems with DPI but does not make a compelling case. See http://en.wikipedia.org/wiki/Deep_packet_inspection#Deep_Packet_Inspection_at_Internet_service_providers http://en.wikipedia.org/wiki/Deep_packet_inspection#Deep_Pac... for some uses of DPI at the ISP level. Each of these use cases has negative features. Those are "the problem with DPI".

by pj 18y ago

What is the problem with DPI? It slows down torrent downloads, which are already slow, but speeds up more synchronous activity like web browsing and chatting. Don't we all want that?

Kejistan 18y ago

DPI does not specifically slow down bittorrent traffic or speed up http traffic. DPI filters traffic based on the data in the packet, which affects all traffic. What happens to that traffic is up to the person implementing the DPI. The problem with DPI is that its akin to the post office reading all of your mail.

pj 18y ago
The post office has a similar system, except they charge customers differently to get information to the recipient faster. Overnight costs more than first class for example. If DPI were used to allow customers to pay based on priority, would that be acceptable? For example, if you only want to pay 1 cent per GB for a torrent download that gets packets to you at 1/3 the rate of HTTP packets, which cost 2 cents per GB, would something like that work? I am not proposing it, just continuing the post office analogy.
- Kejistan 18y ago
  I've never understood this analogy. We already pay more for more bandwidth which is supposed to allow us to receive packets faster. This always sounds like they're expecting me to pay twice for service.

silentOpen 18y ago

Those protocol discrimination and QoS concerns are possible results of "deep packet inspection" (how deep?) but just because these results are good does not mean we should accept DPI (~converse fallacy). The article outlines some of the problems with DPI but does not make a compelling case. See http://en.wikipedia.org/wiki/Deep_packet_inspection#Deep_Packet_Inspection_at_Internet_service_providers http://en.wikipedia.org/wiki/Deep_packet_inspection#Deep_Pac... for some uses of DPI at the ISP level. Each of these use cases has negative features. Those are "the problem with DPI".