TiVo Community
TiVo Community
TiVo Community
Go Back   TiVo Community > Main TiVo Forums > TiVo Series3 HDTV DVRs
TiVo Community
Reply
Forum Jump
 
Thread Tools
Old 12-01-2007, 06:50 AM   #691
lrhorer
Registered User
 
Join Date: Aug 2003
Location: San Antonio, Texas, USA
Posts: 6,872
Couldn't care less

Quote:
Originally Posted by mikeyts View Post
Actually I think that it's cool. I only wonder how dynamic the switch between "TiVo Mode" and "Cable Mode" will be, but I'd love to have a TiVo that I could switch temporarily to "Cable Mode" to use the subscription VOD channels, particularly now that some HD ones are starting to appear (my Cox system just added Starz On Demand HD). Access to IPPV and Pay VOD wouldn't hurt either.
Personally, I couldn't care less about VOD or iPPV. I have both available here on a STB and I had them available on the SA 8300HD. I never use them, and I wouldn't on a TiVo which had them, especially since the content could not be recorded. If it costs nothing and doesn't interfere with ordinary TiVo operations, then fine, but if it adds costs or interferes in any way with ordinary TiVo operations, then I don't want it.
lrhorer is offline   Reply With Quote
Old 12-01-2007, 06:51 AM   #692
vstone
Registered User
 
Join Date: May 2002
Location: Martinsville, VA
Posts: 1,223
Quote:
Originally Posted by lrhorer View Post
The CATV plant is engineered and all taps have fixed vaues. The signal cannot simply be "turned up" at the pole. Simply decreasing the size of a tap is not an answer, either. Doing so increases the through loss so that every customer further down the line will suffer lowered levels. How much lower depends on the old and new tap values. Dropping from a 32dB 4-way tap to a 29dB 4-way tap reduces the throughput by less than .03 dB, but dropping from a 14 dB 4-way to an 11 dB 4-way will drop the downstream signal by almost 3.5 dB. Going from an 11 dB 4-way to an 8 dB 4-way will kill the downstream signal completely.

Engineering and retrofitting a single transmission line can costs tens of thousands of dollars. Believe me, I've done it on several occasions, and I had to provide a great deal of justification to get it approved. Unless some new houses were built after the original feeder was built or the original engineer made a mistake - which is highly unlikely - it just won't happen.

All that said, depending on its design, the dongle would not produce any unliveable changes to the signal levels. If the dongle is an RF transmitter only, then a frequency duplexer can be used internally which would have almost no through loss. If it's a transciever, then it's not difficult to bluiid lt with no smaller than a 9dB directional coupler, which only drops the signal 1 dB. In the vast majority of installations, a 1 dB drop in signal level will not be problematical.
I guess I'll just have to take your word on this. All I know is that I had a signal level problem. The cable tech replaced all the splitters, even the cable comp. owned one where cable comes into the house. He wasn't satisfied and went out to the pole to adjust something. Our Internet connection at church was problematic and at the end of about 150 ft of coax. Another tech checked something on the pole, then said the system techs had to replace some pole equipment and it did affect other customers downstream. Apparently the cable comp. doesn't monitor for problems except as reported by the customers. That said, the increase in deployment of digital boxes is probably identifying problems in signal levels and the use of a dongle may identify more, requiring action.
vstone is offline   Reply With Quote
Old 12-01-2007, 07:00 AM   #693
vstone
Registered User
 
Join Date: May 2002
Location: Martinsville, VA
Posts: 1,223
It seems to me that cable modems are generally NOT sytem specific. They meet the DOCSIS spec and you can buy them (or at least could) at Best Buy and Circuit City). I've have three different cable modems and one of them was RCA. One was Motorola on our SA system. I presume SA makes cable modems, but I've never seen one. A little programmable, but lockable, firmware would make it relative easy to mass produce these things for multiple cable systems. Using the the ethernet port instead of the USB port would allow it to serve multiple Tivos (and presumably other devices). Somehow replacing our regular cable modem with a souped up one, as referenced above, would be a great idea, assuming its rreasonably hack proof.
vstone is offline   Reply With Quote
Old 12-01-2007, 07:16 AM   #694
DCIFRTHS
I dumped SDV / cable
 
DCIFRTHS's Avatar
 
Join Date: Jan 2000
Location: New York
Posts: 2,075
Quote:
Originally Posted by PaulS View Post
... As a resident of a town that's supported by an SA head-end, I can only shudder at the prospect of having to wait for, and then attempt to successfully use, one of their boxes.
Quote:
Originally Posted by lrhorer View Post

Shudder or not, that's the situation.
I am also in a SA area... Why do you think that SA will take longer to engineer a solution? Is SA known for not "playing nice"?
DCIFRTHS is offline   Reply With Quote
Old 12-01-2007, 07:58 AM   #695
Luke M
Registered User
 
Join Date: Nov 2002
Posts: 346
Quote:
Originally Posted by lrhorer View Post
It has to be. Different manufacturer's systems are not compatible.
It's a choice. The dongle could be as simple as a standard cable modem. But that would be a more complex development effort. The quick-and-dirty approach is to simply mimic a set top box.

So I would expect the dongles to be based on a set top box, not a cable modem.
Luke M is offline   Reply With Quote
Old 12-01-2007, 09:39 AM   #696
PaulS
Registered User
 
Join Date: Sep 2002
Location: Southern NH
Posts: 584
Quote:
Originally Posted by vstone View Post
It seems to me that cable modems are generally NOT sytem specific. They meet the DOCSIS spec and you can buy them (or at least could) at Best Buy and Circuit City). I've have three different cable modems and one of them was RCA. One was Motorola on our SA system. I presume SA makes cable modems, but I've never seen one. A little programmable, but lockable, firmware would make it relative easy to mass produce these things for multiple cable systems. Using the the ethernet port instead of the USB port would allow it to serve multiple Tivos (and presumably other devices). Somehow replacing our regular cable modem with a souped up one, as referenced above, would be a great idea, assuming its rreasonably hack proof.
I was going to post the same thing, but then thought about it for a minute. The interaction between a cable modem and a head-end are likely to be VASTLY different than the interaction between a host and a channel-switching fabric.

I wasn't aware that Motorola had such small, or cost reduced, STB designs already in the field. Now that I've seen the DCT-700, or whatever it's called, it's clear that this is probably the box the design of the "dongle" is based upon. Add a USB port, some USB control logic, and you're all set.

At least for one tuner. How they'd handle TWO different tuners with one piece of hardware remains to be seen.

Last edited by PaulS : 12-01-2007 at 09:50 AM.
PaulS is offline   Reply With Quote
Old 12-01-2007, 09:46 AM   #697
PaulS
Registered User
 
Join Date: Sep 2002
Location: Southern NH
Posts: 584
Quote:
Originally Posted by DCIFRTHS View Post
I am also in a SA area... Why do you think that SA will take longer to engineer a solution? Is SA known for not "playing nice"?
SA is known (at least to me, and watching various threads here and at AVS) to produce inferior gear, from both a hardware and software perspective. Motorola always seems to be more active and reactive to problems and solutions that need to be delivered.

Compare the DVRs that the two companies field. The Motorola, despite the remote control latency issue, appears to be generally well-liked. The SA, on the other hand, is nearly universally reviled and considered to be a steaming pile.

Compare the CableCARDs that each company fields. At the initial S3 and TiVoHD roll-outs, there were far fewer problems with Motorola cards than the comparable SA ones.

Things may change, now that SA is owned by Cisco, but I'd tend to doubt that.
PaulS is offline   Reply With Quote
Old 12-01-2007, 10:37 AM   #698
terrible_towel
Registered User
 
Join Date: Oct 2007
Posts: 12
Hi there.. I didn't see it mentioned in this thread, but COX in Hampton Roads, VA (at least in Newport News) has started SDV with the 4 new HD channels from a few weeks ago.

I just wanted to add us to the list...

With FIOS on my street, I guess its good bye COX ...
terrible_towel is offline   Reply With Quote
Old 12-01-2007, 12:33 PM   #699
morac
Cat God
 
morac's Avatar
 
Join Date: Mar 2003
Location: NJ
Posts: 6,534
Quote:
Originally Posted by PaulS View Post
At least for one tuner. How they'd handle TWO different tuners with one piece of hardware remains to be seen.
It should be a non-issue since the tuners are actually in the TiVo, not the dongle. I would think that one transceiver should be all that's required to make multiple requests (one for each tuner).

Now the cable system has to be smart enough to know that the second request isn't replacing the first one, but is in addition to it, but since the cable provider's DVRs also contain 2 tuners this should not be an issue either.

The only potential hiccup I could see is where both tuners need to change at exactly the same time, but if implemented correctly this should also be a non-issue.
morac is offline   Reply With Quote
Old 12-01-2007, 12:36 PM   #700
mikeyts
Wireless Wiseguy
 
Join Date: Jul 2004
Location: San Diego, CA, USA
Posts: 2,131
Quote:
Originally Posted by lrhorer View Post
Personally, I couldn't care less about VOD or iPPV. I have both available here on a STB and I had them available on the SA 8300HD. I never use them, and I wouldn't on a TiVo which had them, especially since the content could not be recorded. If it costs nothing and doesn't interfere with ordinary TiVo operations, then fine, but if it adds costs or interferes in any way with ordinary TiVo operations, then I don't want it.
Don't worry--they're not going to be implementing this on current model TiVos which physically lack the necessary transceiver for the OOB back-channel necessary to support OCAP. Conceivably it could be done with some version of "the dongle" but it seems highly unlikely.

Obviously, they're not gonna be doing this for you . I myself very rarely use VOD or IPPV; in the past couple of years I've only ever rented movies to try HD VOD and didn't find it a very satisfying experience. Every now and then I'll watch and like a recently launched premium cable series and use Subscription VOD to go back and watch all of the earlier episodes in order to catch up with the story. If VOD is ever improved to offer a more responsive interface (and better HD PQ--lots of "macroblocking" defects in fast action scenes in the couple of movies that I tried, Shrek 2 and The Island), it might be more appealing for me.

However, I've heard several TiVo users in this forum bemoan the lack of VOD and IPPV, and few who say that they lease a cable STB in addition to their TiVo so that they can use it, so there's definitely a market for it. Cable is dreaming up further OCAP-enabled interactive offerings so there's no telling whether they'll come up with some "must have" service at some point. For the moment, if they get this SDV tuning resolver out, I'll be satisfied with my Series 3.
__________________
Mike Scott

"
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
" -- hookbill
mikeyts is online now   Reply With Quote
Old 12-01-2007, 12:44 PM   #701
mikeyts
Wireless Wiseguy
 
Join Date: Jul 2004
Location: San Diego, CA, USA
Posts: 2,131
Quote:
Originally Posted by morac View Post
It should be a non-issue since the tuners are actually in the TiVo, not the dongle. I would think that one transceiver should be all that's required to make multiple requests (one for each tuner).
Sheesh, people, could you give this a rest? They do not need a transceiver for each tuner any more than you need one cable modem for every web page that you're browsing simultaneously. They didn't need one freakin' CableCARD for every tuner and there are now single M-Cards operating in TiVo HDs doing decryption for both tuners simultaneously; that's an order-of-magnitude more difficult thing to do than handle the occasional change of channel, which almost never will be done simultaneously.
__________________
Mike Scott

"
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
" -- hookbill
mikeyts is online now   Reply With Quote
Old 12-01-2007, 02:20 PM   #702
lrhorer
Registered User
 
Join Date: Aug 2003
Location: San Antonio, Texas, USA
Posts: 6,872
Docsis

Quote:
Originally Posted by vstone View Post
It seems to me that cable modems are generally NOT sytem specific. They meet the DOCSIS spec and you can buy them (or at least could) at Best Buy and Circuit City).
That's true, but SDV is not DOCSIS, at least not with Scientific Atlanta's implementation. Under OpenCable 2.0, DOCSIS and separable security are convergent technologies, but OpenCable 2.0 has not been ratified.

Quote:
Originally Posted by vstone View Post
I presume SA makes cable modems, but I've never seen one.
'Not as far as I know.

Quote:
Originally Posted by vstone View Post
A little programmable, but lockable, firmware would make it relative easy to mass produce these things for multiple cable systems.
Nope. Unfortunately, not. I believe (but am not certain) the Motorola system is fully compatible with DOCSIS. Scientific Atlanta is not. I suspect C-Cor isn't, either. That said, they couldbe made to work with a DOCSIS modem, even though the systems are incompatible. It would require putting what is essentially a VPN endpoint on the DOCSIS modem and tying the VPN stream into the CATV servers.

Quote:
Originally Posted by vstone View Post
Using the the ethernet port instead of the USB port would allow it to serve multiple Tivos (and presumably other devices). Somehow replacing our regular cable modem with a souped up one, as referenced above, would be a great idea, assuming its rreasonably hack proof.
Amen.

Last edited by lrhorer : 12-01-2007 at 02:51 PM.
lrhorer is offline   Reply With Quote
Old 12-01-2007, 02:22 PM   #703
lrhorer
Registered User
 
Join Date: Aug 2003
Location: San Antonio, Texas, USA
Posts: 6,872
Multiple Dongles

Quote:
Originally Posted by mikeyts View Post
Sheesh, people, could you give this a rest? They do not need a transceiver for each tuner any more than you need one cable modem for every web page that you're browsing simultaneously. They didn't need one freakin' CableCARD for every tuner and there are now single M-Cards operating in TiVo HDs doing decryption for both tuners simultaneously; that's an order-of-magnitude more difficult thing to do than handle the occasional change of channel, which almost never will be done simultaneously.
It won't require one dongle per tuner. It will most certainly require one dongle per TiVo or any other receiver. I'm looking at a minimum of three.
lrhorer is offline   Reply With Quote
Old 12-01-2007, 02:31 PM   #704
lrhorer
Registered User
 
Join Date: Aug 2003
Location: San Antonio, Texas, USA
Posts: 6,872
Sdv

Quote:
Originally Posted by mikeyts View Post
Don't worry--they're not going to be implementing this on current model TiVos which physically lack the necessary transceiver for the OOB back-channel necessary to support OCAP. Conceivably it could be done with some version of "the dongle" but it seems highly unlikely.
I'm aware of that, and I'm not worried about the the current versions of TiVo in this respect. I'm concerned about future versions of the TiVo.

Quote:
Originally Posted by mikeyts View Post
I myself very rarely use VOD or IPPV; in the past couple of years I've only ever rented movies to try HD VOD and didn't find it a very satisfying experience.
I had to support it when I worked for the CATV company, so I worked with both iPPV and VOD when I was with them, but VOD was far too much a PITA and the TiVo made searching the VOD streams a futile exercise. I've never seen anything on iPPV I wanted to purchase, even when I as an employee got a large discount on iPPV events.
lrhorer is offline   Reply With Quote
Old 12-01-2007, 02:33 PM   #705
lrhorer
Registered User
 
Join Date: Aug 2003
Location: San Antonio, Texas, USA
Posts: 6,872
Don't doubt it

Quote:
Originally Posted by PaulS View Post
Things may change, now that SA is owned by Cisco, but I'd tend to doubt that.
I don't know why you would doubt it. I think it is extremely likely it will get much worse.
lrhorer is offline   Reply With Quote
Old 12-01-2007, 02:39 PM   #706
lrhorer
Registered User
 
Join Date: Aug 2003
Location: San Antonio, Texas, USA
Posts: 6,872
Straighten it out

Quote:
Originally Posted by Luke M View Post
It's a choice. The dongle could be as simple as a standard cable modem. But that would be a more complex development effort. The quick-and-dirty approach is to simply mimic a set top box.

So I would expect the dongles to be based on a set top box, not a cable modem.
No. The TiVo (or other receiver) has all the widgets which mimic the STB, except the transmitter and the resolver. The transmitter is a simple RF modulator essentially identical to that found in a cable modem (for Motorola, and similar for Scientific Atlanta). The resolver is just a small CPU similar to that found in both STBs and Modems. The dongle as a whole is much more nearly a modem than an STB.
lrhorer is offline   Reply With Quote
Old 12-01-2007, 02:42 PM   #707
PaulS
Registered User
 
Join Date: Sep 2002
Location: Southern NH
Posts: 584
Quote:
Originally Posted by lrhorer View Post
I don't know why you would doubt it. I think it is extremely likely it will get much worse.
I was being generous.
PaulS is offline   Reply With Quote
Old 12-01-2007, 02:48 PM   #708
PaulS
Registered User
 
Join Date: Sep 2002
Location: Southern NH
Posts: 584
Quote:
Originally Posted by mikeyts View Post
Sheesh, people, could you give this a rest? They do not need a transceiver for each tuner any more than you need one cable modem for every web page that you're browsing simultaneously. They didn't need one freakin' CableCARD for every tuner and there are now single M-Cards operating in TiVo HDs doing decryption for both tuners simultaneously; that's an order-of-magnitude more difficult thing to do than handle the occasional change of channel, which almost never will be done simultaneously.
Oh, so you mean I can return one of the S-Cards that's in my S3 right now ? Didn't think so...

I'm not familiar with the exact details of the SDV implementations, but I am very familiar with the IP multicast semantics that CableLabs borrowed heavily from to draft the functionality. The dongle is going to have to represent multiple (probably two) logical entities in it's communcations upstream. Essentially, it's gonna have to behave like two separate boxes (or computers, in the IP multicast model) in one physical device. Were the SDV functions to be keyed to a physical ID (MAC address, or what have you), then they'd be up the creek from the get go...

Until we see what they have in store for the dongle, this is all speculation. To argue over unknown details is pointless.
PaulS is offline   Reply With Quote
Old 12-01-2007, 02:50 PM   #709
lrhorer
Registered User
 
Join Date: Aug 2003
Location: San Antonio, Texas, USA
Posts: 6,872
Interaction

Quote:
Originally Posted by PaulS View Post
I was going to post the same thing, but then thought about it for a minute. The interaction between a cable modem and a head-end are likely to be VASTLY different than the interaction between a host and a channel-switching fabric.
Well, yes, but the difference is a software protocol issue, not a hardware one. Motorola's SDV platform is compatible with DOCSIS and to many intents and purposes the DCT-700 is a specialized DOCSIS modem with a video section added. The dongle doesn't need a video section, though.

Quote:
Originally Posted by PaulS View Post
At least for one tuner. How they'd handle TWO different tuners with one piece of hardware remains to be seen.
That's trivial. The tuning resolver is a fairly dumb bit of hardware. All it does is provide layer I networking to the CATV headend. The host (or the host section of the DCT-700) handles the communications, and all it needs to be able to do is present two MAC addresses to the headend and speak independantly on both of them. This can be trivially handled in software.
lrhorer is offline   Reply With Quote
Old 12-01-2007, 03:01 PM   #710
lrhorer
Registered User
 
Join Date: Aug 2003
Location: San Antonio, Texas, USA
Posts: 6,872
Not at all

Quote:
Originally Posted by PaulS View Post
The dongle is going to have to represent multiple (probably two) logical entities in it's communcations upstream.
True.

Quote:
Originally Posted by PaulS View Post
Essentially, it's gonna have to behave like two separate boxes (or computers, in the IP multicast model) in one physical device.
Well, no. It's just going to have to handle (not manage, the TiVo can do that) two independant data streams, but that's been SOP for years. Routers do it all the time.

Quote:
Originally Posted by PaulS View Post
Were the SDV functions to be keyed to a physical ID (MAC address, or what have you), then they'd be up the creek from the get go...
Not at all. First of all, spoofing two MAC addresses on a single interface is not difficult. Secondly, if the Dongle acts like a layer 2 switch, then it will simply pass on the MAC addresses of the CableCards in every packet. The network doesn't care whether the MAC addreses come from two different boxes, or one, as long as they are unique.

Quote:
Originally Posted by PaulS View Post
Until we see what they have in store for the dongle, this is all speculation. To argue over unknown details is pointless.
Well, we have enough details to make some predictions. OTOH, this whole engineering effort has been boneheaded and obtuse from the get-go, so who knows what kludge someone might stick into the mess. Making it work isn't difficult, however.
lrhorer is offline   Reply With Quote
Old 12-01-2007, 03:02 PM   #711
lrhorer
Registered User
 
Join Date: Aug 2003
Location: San Antonio, Texas, USA
Posts: 6,872
Generousity

Quote:
Originally Posted by PaulS View Post
I was being generous.
Very, if you ask me.
lrhorer is offline   Reply With Quote
Old 12-01-2007, 03:08 PM   #712
lrhorer
Registered User
 
Join Date: Aug 2003
Location: San Antonio, Texas, USA
Posts: 6,872
Hard to say

Quote:
Originally Posted by DCIFRTHS View Post
I am also in a SA area... Why do you think that SA will take longer to engineer a solution? Is SA known for not "playing nice"?
In this respect (and since Cisco has taken them over), I don't know. In the past they haven't had problems working with other vendors - specifically Zenith and Pace, to my knowledge - to get third party hardware working with their platform. I do believe the SA standard is available for purchase, and they would be downright stupid to sell an implementation standard and not support it.
lrhorer is offline   Reply With Quote
Old 12-01-2007, 03:09 PM   #713
morac
Cat God
 
morac's Avatar
 
Join Date: Mar 2003
Location: NJ
Posts: 6,534
Quote:
Originally Posted by mikeyts View Post
Sheesh, people, could you give this a rest? They do not need a transceiver for each tuner any more than you need one cable modem for every web page that you're browsing simultaneously.
Since you replied to my post I think you misunderstood my post. I was agreeing with you. The "one per tuner" was referring to the multiple requests (one request per tuner), not the number of transceivers (one).
morac is offline   Reply With Quote
Old 12-01-2007, 03:26 PM   #714
mikeyts
Wireless Wiseguy
 
Join Date: Jul 2004
Location: San Diego, CA, USA
Posts: 2,131
Quote:
Originally Posted by PaulS View Post
Oh, so you mean I can return one of the S-Cards that's in my S3 right now ? Didn't think so...

I'm not familiar with the exact details of the SDV implementations, but I am very familiar with the IP multicast semantics that CableLabs borrowed heavily from to draft the functionality. The dongle is going to have to represent multiple (probably two) logical entities in it's communcations upstream. Essentially, it's gonna have to behave like two separate boxes (or computers, in the IP multicast model) in one physical device. Were the SDV functions to be keyed to a physical ID (MAC address, or what have you), then they'd be up the creek from the get go...

Until we see what they have in store for the dongle, this is all speculation. To argue over unknown details is pointless.
No you can't return one of the cards in your S3 right now, but TiVo has stated that they're working on making a single M-Card work in multi-stream mode on the S3. It was designed to support a single M-Card and they advertised that a single M-Card would work in it at every product show that they brought the thing to. Unfortunately, the M-Card spec wasn't finalized until after they shipped S3, so there was no way that they could make whatever final tweaks they needed to their implementation and get it certified in time, but they're trying to do it after the fact now. TiVo HD, on the other hand, launched already certified for M-Card and can use either a single M-Card for both tuners or two S-Cards, as TiVo S3 was supposed to, and people are using single M-Cards to serve both tuners now. Both SA and Motorola have introduced cable STBs which use single M-Cards for two-tuner DVR operation which are in use in the field now (the FCC forbids cable providers to buy any more leased STBs which work without CableCARD since July this year).

The other issue with replacing your two S-Cards with a single M-Card is that nothing compells your cable operator to do that. Nothing compells them to stock M-Cards at all except for their own needs for provisioning them in their mandatory CableCARD-enabled leased STBs. Even if they have one, they don't have to give you one, so once TiVo makes it work in S3, you're not guaranteed of being able to switch.

It is useless to speculate as to exactly how the tuning resolver is going to work until it ships, but useless speculation as to how new features will work and what they'll cost is half of what we do here in these forums. It's my opinion (as someone who worked on firmware in networking devices for 15 years) that your speculation that it'd require two tranceivers to support SDV for two tuners is specious. For one thing, SDV is a technology that was intended to be (and is currently) supported by a downloadable app running in an OCAP platform and OCAP doesn't specify or permit multiple backward comm paths to the network.
__________________
Mike Scott

"
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
" -- hookbill

Last edited by mikeyts : 12-01-2007 at 03:33 PM.
mikeyts is online now   Reply With Quote
Old 12-01-2007, 04:26 PM   #715
PaulS
Registered User
 
Join Date: Sep 2002
Location: Southern NH
Posts: 584
Quote:
Originally Posted by mikeyts View Post
No you can't return one of the cards in your S3 right now, but TiVo has stated that they're working on making a single M-Card work in multi-stream mode on the S3.
That's all fine and dandy, but from comments made by TiVo reps on this very forum, it's not looking very good for multi-stream support on M-Cards on the S3. Not sure if it's a hardware or driver issue, or TiVo having problems with the card component supplier, but TiVoStephen didn't seem too optomistic about the chances of getting it supported.



Quote:
Originally Posted by mikeyts View Post
It is useless to speculate as to exactly how the tuning resolver is going to work until it ships, but useless speculation as to how new features will work and what they'll cost is half of what we do here in these forums. It's my opinion (as someone who worked on firmware in networking devices for 15 years) that your speculation that it'd require two tranceivers to support SDV for two tuners is specious. For one thing, SDV is a technology that was intended to be (and is currently) supported by a downloadable app running in an OCAP platform and OCAP doesn't specify or permit multiple backward comm paths to the network.
I also have exactly 15 years worth of development firmware for both routers and switches, so I feel I have a DAMN good idea of exactly what goes on under the covers. So, you can lose the uppity condescending tone, for starters...

I never said that they'd need two separate transceivers in the dongle. I said they'd need to behave like there were two logical entities in the box. Not the same. MAC spoofing is certainly a simple thing to accomplish, but the question is whether of not the head-end and switching fabric can deal with it.

Last edited by PaulS : 12-01-2007 at 05:24 PM.
PaulS is offline   Reply With Quote
Old 12-01-2007, 05:29 PM   #716
PaulS
Registered User
 
Join Date: Sep 2002
Location: Southern NH
Posts: 584
Quote:
Originally Posted by lrhorer View Post
Well, yes, but the difference is a software protocol issue, not a hardware one. Motorola's SDV platform is compatible with DOCSIS and to many intents and purposes the DCT-700 is a specialized DOCSIS modem with a video section added. The dongle doesn't need a video section, though.


That's trivial. The tuning resolver is a fairly dumb bit of hardware. All it does is provide layer I networking to the CATV headend. The host (or the host section of the DCT-700) handles the communications, and all it needs to be able to do is present two MAC addresses to the headend and speak independantly on both of them. This can be trivially handled in software.
Then it definitely sounds like a firmware upgrade gets the job done. I wonder why it even took them this long to get the solution finalized... Then again, it doesn't surprise me, this is CableLabs afterall.

As a funny aside, with all the Cisco talk lately, it gets me to remembering way back when, when I was a little co-op student working for Cabletron back in the day, before the router market had really matured. The rumor mill was abuzz that we were gonna buy this small outfit from California called Cisco. It obviously never happened, Cisco went on to rule the rule, Cabletron went down in flames with all sorts of financial irregularities and cooking of books, and the rest is history...
PaulS is offline   Reply With Quote
Old 12-01-2007, 05:32 PM   #717
mikeyts
Wireless Wiseguy
 
Join Date: Jul 2004
Location: San Diego, CA, USA
Posts: 2,131
Quote:
Originally Posted by PaulS View Post
That's all fine and dandy, but from comments made by TiVo reps on this very forum, it's not looking very good for multi-stream support on M-Cards on the S3. Not sure if it's a hardware or driver issue, but TiVoStephen didn't seem too optomistic about the chances of getting it supported.
I don't know what the issues are, but I know that they intended for it to support M-Cards in multi-stream mode from day one and it was a bullet-point in all of their old presentations for the product. Maybe there was some subtle change in hardware requirements made to the M-Card spec after they shipped S3. My point is that the M-Card spec is there and supports decryption and re-encryption of six simultaneous service streams for a single device that it's installed in. One M-Card is currently supporting two tuners on a number of products, including TiVo HD, and could be used to support even more tuners in future products. To my mind, there's little reason the tuning resolver could not support multiple tuners with a single physical path of communication to the network.

(EDIT: The way that one M-Card supports multiple streams is detailed in Multi-Stream CableCARD Interface specification. CableLabs made changes to their site last week making the path to this document a lot harder to find now).
Quote:
I also have exactly 15 years worth of development firmware for both routers and switches, so I feel I have a DAMN good idea of exactly what goes on under the covers. So, you can lose the uppity condescending tone, for starters...

I never said that they'd need two separate transceivers in the dongle. I said they'd need to behave like there were two logical entities in the box. Not the same. MAC spoofing is certainly a simple thing to accomplish, but the question is whether of not the head-end and switching fabric can deal with it.
Glad to know that you know where you're coming from too. I was not trying to be snooty, just letting you know from whence my opinion comes. Given that you have some similar experience, I'm a little surprised that you'd think that there'd be any difficulty supporting this application for two tuners using a single communications path back to the network. Given my experience with networking design the idea that a single device would need more than one physical path back to the network to make requests for tuning information for multiple tuners seems ludicrous. We obviously have very different conceptions of the situation. To my mind, tuning resolution is an application level service offered to a host device, not to one or more physical tuners.
__________________
Mike Scott

"
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
" -- hookbill

Last edited by mikeyts : 12-01-2007 at 05:48 PM.
mikeyts is online now   Reply With Quote
Old 12-01-2007, 06:03 PM   #718
PaulS
Registered User
 
Join Date: Sep 2002
Location: Southern NH
Posts: 584
Quote:
Originally Posted by mikeyts View Post
Glad to know that you know where you're coming from too. I was not trying to be snooty, just letting you know from whence my opinion comes.
No sweat.

Quote:
Originally Posted by mikeyts View Post
Given that you have some similar experience, I'm a little surprised that you'd think that there'd be any difficulty supporting this application for two tuners using a single communications path back to the network. Given my experience with networking design the idea that a single device would need more than one physical path back to the network to make requests for tuning information for multiple tuners seems ludicrous. We obviously have very different conceptions of the situation. To my mind, tuning resolution is an application level service offered to a host device, not to one or more physical tuners.
The concept and application is simple, and has been accomplished every day without even thinking about it for years and years. In the data world.

However, this is the video world, ruled by the NCTA, CableLabs, and whatever media lobbyists are cutting the checks this week. These guys could screw up a free lunch. It wouldn't surprise me at all if the cable guys tried to cook up their own flavor of multicast video service and couldn't get it to fly, so they went back to the IGMP RFCs with their crayons and substituted "video" for "data" and called it a day. These guys are NOT rocket scientists.
PaulS is offline   Reply With Quote
Old 12-01-2007, 07:21 PM   #719
lrhorer
Registered User
 
Join Date: Aug 2003
Location: San Antonio, Texas, USA
Posts: 6,872
CATV Problems

Quote:
Originally Posted by vstone View Post
I guess I'll just have to take your word on this. All I know is that I had a signal level problem. The cable tech replaced all the splitters, even the cable comp. owned one where cable comes into the house. He wasn't satisfied and went out to the pole to adjust something.
Unless he replaced a tap, directional coupler, a trap, or some other passive device one for one, then (unless he was committing a serious breech of engineering rules), what he did was balance the amplifier which feeds your neighborhood (or one of the amps which feeds it). If the tilt or gain of an amp is out of kilter, then there are gain and tilt controls to bring the amp back into spec. The point is the output levels do have a particular specification, and it is improper to ignore that specification in order to get the consumer "a little better signal". Soing so only makes things worse.

Quote:
Originally Posted by vstone View Post
Our Internet connection at church was problematic and at the end of about 150 ft of coax. Another tech checked something on the pole, then said the system techs had to replace some pole equipment and it did affect other customers downstream. Apparently the cable comp. doesn't monitor for problems except as reported by the customers.
There are addressible devices, but they cost well over $500 each, and putting addressible devices at each tap location can also triple the number of power supplies at over $4000 each. A typical CATV plant may have 50,000 or more subsrcriber taps and up tp 100 power supplies, and is generally speaking pretty stable. Do the math.[/quote]

Quote:
Originally Posted by vstone View Post
That said, the increase in deployment of digital boxes is probably identifying problems in signal levels.
It is. The STBs and DVRs themselves are addressible and most can report something about their input levels. There is most certainly a report if one stops talking.
lrhorer is offline   Reply With Quote
Old 12-02-2007, 08:04 AM   #720
mel.simmons
Registered User
 
Join Date: Mar 2002
Location: Del Mar CA
Posts: 24
SDV Deployment List

Light Reading has posted a list of SDV deployments in the US. No details on the number of channels that have been switched in each market, but this list gives an indication of the rapid movement to SDV. It's time for a dongle to appear. You might also notice that almost all of the listed projects are using the Scientific Atlanta platform, making that the priority for a dongle.
http://www.lightreading.com/blog.asp...&doc_id=139512
mel.simmons is offline   Reply With Quote
Reply
Forum Jump




Thread Tools


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Advertisements

TiVo Community
Powered by vBulletin® Version 3.6.8
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
vBulletin Skins by: Relivo Media

(C) 2013 Magenium Solutions - All Rights Reserved. No information may be posted elsewhere without written permission.
TiVoŽ is a registered trademark of TiVo Inc. This site is not owned or operated by TiVo Inc.
All times are GMT -5. The time now is 05:23 PM.
OUR NETWORK: MyOpenRouter | TechLore | SansaCommunity | RoboCommunity | MediaSmart Home | Explore3DTV | Dijit Community | DVR Playground |