On Mon, 28 Mar 2005 07:20:43 -0600, DanS
<(E-Mail Removed)> wrote:
>My question is really, how well does it work? CW designed and deployed
>their own proprietary equipment in the networks before the purchase. The
>original OEM equipment was 2.4 ghz, a bit slow, but the design offered a
>25 mile link distance, at full bandwidth with no speed degradation. Also,
>the OEM stuff was not just a wireless bridge but an actual router. With
>residential wireless, the biggest issue with subscriber's is having a big
>ugly antenna at their location. With the buyout, and a switch to the
>current hardware, that requirement was supposed to be minimized and most
>are supposedly able to use this small little box with it's own antenna.
>I'm just wondering how well it works.
I'm not a Clearwire customer or employee, but think I can guess how it
works. Blocking incoming ports (to the customer) does not require
anything at the customer end. It's done by the central router which
is probably some very big Cisco or equivalent monster router. All it
needs to do is look at the incoming ethernet packets, inspect the
destination port number (i.e. 80) and just drop the packet. Nothing
on port 80 ever gets transmitted or arrives at the customers.
Dealing with outgoing port 25 blocking is a bit more difficult. One
could easily have the big central router do all the work in the same
way. However, that means that the packets destined to port 25 will be
transmitted by the client radio before getting dropped by the central
router. That's a waste of precious airtime. If the CPE (customer
premisis equipment) really does have a built in router, then outgoing
port 25 packets are best dropped at the source. The mechanism is the
same. The router inspects the destination port number and drops
anything on port 25. I can't tell from here which way outgoing port
blocking is implemented. It might also be both at the central router
and the CPE router. If there's no CPE router, then it all has to be
done at the central router.
What I find interesting is that Clearwire is apparently also blocking
ports used by Vonage VoIP SIP phones. Since Clearwire is not a common
carrier, there's no legal restriction preventing this practice.
However, in my never humble political opinion, they're just asking to
get legislated into the ground in the upcoming revision to the Telecom
Act which will include VoIP guidelines. It also begs the question of
"what's next?" Are they going to filter VPN's, streaming video, file
sharing, and competitors web sites? Maybe they won't absolutely block
services, but simply slow them down? These have been tried by other
ISP's with universally dismal results.
--
Jeff Liebermann
(E-Mail Removed)
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 AE6KS 831-336-2558