On Mar 6, 2009, at 8:22 PM, Wes Felter wrote:
Localization was getting a little over-hyped so I like this
document. Here are some suggestions:
I didn't see any mention of traditional ISP-operated HTTP caches
(not CDNs), their discovery protocols (WPAD), and their legal
status. These may have fallen in popularity in recent years as the
cost of transit has dropped, but clearly some ISPs still use them
(as you can see by searching for "caching youtube").
Good point, although the biggest problem is the failure behavior:
When Akamai fails its bad enough, when the cache in transit fails, its
worse.
This draft may want to reference BEP 22 (http://bittorrent.org/beps/bep_0022.html
) as a strawman cache discovery protocol.
Thanks.
AFAIK, many P2P caches available today are expensive inline DPI-
based devices due to the lack of a discovery protocol, so I think
this draft understates the cost savings possible due to a good cache
discovery protocol.
Which I don't get. You don't need to be INLINE to do the necessary
DPI, thats the great thing about P2P: you do an out-of-path IDS mirror
to get the metadata and then pass it off to the cache which then does
everything else.
I think if ISPs really want to save bandwidth they will have to
cache as much as possible, not just "registered" legal content.
IANAL but the DMCA appears to allow this. Traditional HTTP caches
cache everything (certainly there is plenty of pirated content
flowing over HTTP), so I don't see why P2P would be different.
There is a difference between "may allow" and "worth fighting".
Youtube is clearly allowed under the DMCA, but they go through a huge
amount of effort to avoid hosting copyright violations, rather than
just relying on the DMCA safe-harbor provisions which should be
legally sufficient.
The few ISP operators I've talked to are very VERY nervous about
caching pirated content, not just because of the lawsuits (even if you
win, you lose because of the cost), but because they also need to be
partners with the big hollywood content providers because of other
corporate interests (what major ISP in the US is not either a telco
that wants to be a cable co or a cable co that wants to be a telco?).
Thus "cache everything" i don't think is a viable option for the big
ISPs.
But the key is "when legal shifts to P2P" (eg, like CNN's live video
streaming), they must be able to cache it, because this is obviously
coming down the pike, and spells bad news if it happens without caching.
Basically, of the ISPs I've talked to, the necessary requirements for
a P2P edge cache are
a) Out of path only.
b) No DPI required at all.
c) Protections so only legitimate content is cached.
A and B in particular require notification, and interact strongly with
localization.
Wes Felter - [email protected] - http://felter.org/wesley/
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