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uk.telecom.broadband (UK broadband) (uk.telecom.broadband) Discussion of broadband services, technology and equipment as provided in the UK. Discussions of specific services based on ADSL, cable modems or other broadband technology are also on-topic. Advertising is not allowed.

Multicast on 21CN



 
 
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  #1  
Old March 16th 08, 07:08 PM posted to uk.telecom.broadband
DAB sounds worse than FM
external usenet poster
 
Posts: 138
Default Multicast on 21CN

The first article on

http://www.samknows.com/broadband/

says at the bottom:

"The afternoon was wrapped up with a proof of concept demonstration of video
content distribution in the 21CN network. Using Assured Rate QoS, BT showed
how content could be distributed from the core, from one of their 20
aggregation points or from the MSANs themselves (which will be present in
all exchanges in the UK). Distribution at this level is made possible by
using multicast, which is not available on the current BT IPStream product
range."

Could someone say whether what BT is doing will fix the problem PlusNet
describes on its blog entry below (I think it does, because it says that
multicast can be distributed from the different levels of the 21CN, and
PlusNet says that they want it split further down the line):

http://community.plus.net/blog/2008/...t-of-ipstream/

"The same thing applies with multicast. Multicast can be used to more
efficiently distribute content. A number of customers wanted to watch the
same video stream then using multicast rather than there being one stream
per customer between the content provider and the end user, where the
network paths are the same there only needs to be one stream. At the moment
on IPStream that would mean that if you were watching a multicast stream
there would only need to be one stream between the content provider and the
ISP's network and it splits into multiple feeds at central pipes.

Which of course is the major problem with using multicast at the moment, the
only cost saving to the ISP is the transit and/or peering costs, which as we've
seen above may not represent any real savings or at best only a tiny
reduction because you still have one stream per customer going across the
central pipes.

For multicast to be successful in the UK the stream must be split further
down the line, preferably at the BT PoP but at the very least at the local
exchanges. This is something we might see as part of BT's 21st Century
Network upgrades which are taking place over the next few years."




--
Steve - www.digitalradiotech.co.uk - Digital Radio News & Info

The adoption of DAB was the most incompetent technical
decision ever made in the history of UK broadcasting:
http://www.digitalradiotech.co.uk/da...ion_of_dab.htm


  #2  
Old March 16th 08, 07:15 PM posted to uk.telecom.broadband
Andy Burns
external usenet poster
 
Posts: 56
Default Multicast on 21CN

On 16/03/2008 19:08, DAB sounds worse than FM wrote:

Using Assured Rate QoS


Isn't that one of the aspects of 21CN that BT will require you to
*really* open your wallet wide for?

  #3  
Old March 16th 08, 07:37 PM posted to uk.telecom.broadband
Mark
external usenet poster
 
Posts: 33
Default Multicast on 21CN

On Sun, 16 Mar 2008 19:08:40 GMT, "DAB sounds worse than FM"
[email protected] wrote:

The first article on

http://www.samknows.com/broadband/

says at the bottom:

"The afternoon was wrapped up with a proof of concept demonstration of video
content distribution in the 21CN network. Using Assured Rate QoS, BT showed
how content could be distributed from the core, from one of their 20
aggregation points or from the MSANs themselves (which will be present in
all exchanges in the UK). Distribution at this level is made possible by
using multicast, which is not available on the current BT IPStream product
range."

Could someone say whether what BT is doing will fix the problem PlusNet
describes on its blog entry below (I think it does, because it says that
multicast can be distributed from the different levels of the 21CN, and
PlusNet says that they want it split further down the line):

http://community.plus.net/blog/2008/...t-of-ipstream/

"The same thing applies with multicast. Multicast can be used to more
efficiently distribute content. A number of customers wanted to watch the
same video stream then using multicast rather than there being one stream
per customer between the content provider and the end user, where the
network paths are the same there only needs to be one stream. At the moment
on IPStream that would mean that if you were watching a multicast stream
there would only need to be one stream between the content provider and the
ISP's network and it splits into multiple feeds at central pipes.

Which of course is the major problem with using multicast at the moment, the
only cost saving to the ISP is the transit and/or peering costs, which as we've
seen above may not represent any real savings or at best only a tiny
reduction because you still have one stream per customer going across the
central pipes.

For multicast to be successful in the UK the stream must be split further
down the line, preferably at the BT PoP but at the very least at the local
exchanges. This is something we might see as part of BT's 21st Century
Network upgrades which are taking place over the next few years."


The way I read it, it doe fix the problem. Frankly it would be
pointless to build a NGN like 21CN that didn't.

Multicast has to work from head-end (wherever that is) through to the
user (a set-top box for example) in order to save aggregation network
bandwidth for applications like IPTV.

  #4  
Old March 16th 08, 08:09 PM posted to uk.telecom.broadband
DAB sounds worse than FM
external usenet poster
 
Posts: 138
Default Multicast on 21CN

Mark wrote:
On Sun, 16 Mar 2008 19:08:40 GMT, "DAB sounds worse than FM"
[email protected] wrote:

The first article on

http://www.samknows.com/broadband/

says at the bottom:

"The afternoon was wrapped up with a proof of concept demonstration
of video content distribution in the 21CN network. Using Assured
Rate QoS, BT showed how content could be distributed from the core,
from one of their 20 aggregation points or from the MSANs themselves
(which will be present in
all exchanges in the UK). Distribution at this level is made
possible by
using multicast, which is not available on the current BT IPStream
product range."

Could someone say whether what BT is doing will fix the problem
PlusNet describes on its blog entry below (I think it does, because
it says that multicast can be distributed from the different levels
of the 21CN, and PlusNet says that they want it split further down
the line):

http://community.plus.net/blog/2008/...t-of-ipstream/

"The same thing applies with multicast. Multicast can be used to more
efficiently distribute content. A number of customers wanted to
watch the
same video stream then using multicast rather than there being one
stream
per customer between the content provider and the end user, where the
network paths are the same there only needs to be one stream. At the
moment
on IPStream that would mean that if you were watching a multicast
stream
there would only need to be one stream between the content provider
and the ISP's network and it splits into multiple feeds at central
pipes.

Which of course is the major problem with using multicast at the
moment, the only cost saving to the ISP is the transit and/or
peering costs, which as we've seen above may not represent any real
savings or at best only a tiny
reduction because you still have one stream per customer going
across the central pipes.

For multicast to be successful in the UK the stream must be split
further
down the line, preferably at the BT PoP but at the very least at the
local exchanges. This is something we might see as part of BT's 21st
Century
Network upgrades which are taking place over the next few years."


The way I read it, it doe fix the problem. Frankly it would be
pointless to build a NGN like 21CN that didn't.



I agree, but just on Friday I was searching for info on whether the 21CN
would support multicast and the only mention I could find anywhere was on a
Griffin Internet web page which said it was "on the roadmap", and PlusNet
didn't seem too sure on their blog either. Anyway, at least they've
demonstrated it.

How long do you reckon it might be before BT actually launches it?

Tiscali's chief exec says their network support multicast as well, BTW:

http://networks.silicon.com/broadban...118,00.htm?r=2


Multicast has to work from head-end (wherever that is) through to the
user (a set-top box for example) in order to save aggregation network
bandwidth for applications like IPTV.



Yep. The BBC is launching its multicast radio streams as well:

http://www.bbc.co.uk/blogs/radiolabs...our_co_1.shtml

"Ashley Brown asks "Will BBC Radio be getting multicast and MP3 streams?" -
not only will we be getting multicast streams, we've actually had them for a
number of years"

I'd imagine the TV channels multicast streams will launch as well once the
fuss about the iPlayer bandwidth has died down a bit...


--
Steve - www.digitalradiotech.co.uk - Digital Radio News & Info

The adoption of DAB was the most incompetent technical
decision ever made in the history of UK broadcasting:
http://www.digitalradiotech.co.uk/da...ion_of_dab.htm


  #5  
Old March 17th 08, 10:45 AM posted to uk.telecom.broadband
[email protected]
external usenet poster
 
Posts: 735
Default Multicast on 21CN



"DAB sounds worse than FM" [email protected] wrote in message
...
The first article on

http://www.samknows.com/broadband/

says at the bottom:

"The afternoon was wrapped up with a proof of concept demonstration of
video content distribution in the 21CN network. Using Assured Rate QoS, BT
showed how content could be distributed from the core, from one of their
20 aggregation points or from the MSANs themselves (which will be present
in all exchanges in the UK). Distribution at this level is made possible
by using multicast, which is not available on the current BT IPStream
product range."


Demonstrated that to BT more than three years ago!


Could someone say whether what BT is doing will fix the problem PlusNet
describes on its blog entry below (I think it does, because it says that
multicast can be distributed from the different levels of the 21CN, and
PlusNet says that they want it split further down the line):


The system I demonstrated could split the multicast down to the DSLAM
level.. I see no reason why BT can't do that as their exist DSLAMS can with
little modification if any.


http://community.plus.net/blog/2008/...t-of-ipstream/

"The same thing applies with multicast. Multicast can be used to more
efficiently distribute content. A number of customers wanted to watch the
same video stream then using multicast rather than there being one stream
per customer between the content provider and the end user, where the
network paths are the same there only needs to be one stream. At the
moment on IPStream that would mean that if you were watching a multicast
stream there would only need to be one stream between the content provider
and the ISP's network and it splits into multiple feeds at central pipes.

Which of course is the major problem with using multicast at the moment,
the only cost saving to the ISP is the transit and/or peering costs, which
as we've seen above may not represent any real savings or at best only a
tiny reduction because you still have one stream per customer going across
the central pipes.

For multicast to be successful in the UK the stream must be split further
down the line, preferably at the BT PoP but at the very least at the local
exchanges. This is something we might see as part of BT's 21st Century
Network upgrades which are taking place over the next few years."


BT could do it now.. its a case of who is going to pay.
If BT do multicast in the DSLAM then the ISPs are getting something for
nothing.
I remember the time when BT left routing on so stuff on the BT network
didn't transit the ISPs at all.. what did the ISPs do.. setup VPNs and stuff
like that to avoid their pipes and hence the charges.. BT stopped this by
forcing all the data up the ISPs pipe by encapsulating it early on and
putting it in tunnels to the ISP.


One option talked about was adding storage in the DSLAM to buffer video
streams for interactive playback.. ATM you have to go back to the central
server which limits the number of customers per DSLAM that can have
interactive video.. buffering it takes advantage of the fact that many will
be watching the same football match or eastenders so you can get more
customers doing interactive.




  #6  
Old March 17th 08, 10:48 AM posted to uk.telecom.broadband
[email protected]
external usenet poster
 
Posts: 735
Default Multicast on 21CN



"Mark" wrote in message
...



Multicast has to work from head-end (wherever that is) through to the
user (a set-top box for example) in order to save aggregation network
bandwidth for applications like IPTV.


Multicast assumes you are going to have lots of people watching the same
stream at the same time.. rather limiting for interactive services. Good for
broadcast TV but isn't that what the TV network's for?

  #7  
Old March 17th 08, 12:48 PM posted to uk.telecom.broadband
DAB sounds worse than FM
external usenet poster
 
Posts: 138
Default Multicast on 21CN

[email protected] wrote:
"Mark" wrote in message
...



Multicast has to work from head-end (wherever that is) through to
the user (a set-top box for example) in order to save aggregation
network bandwidth for applications like IPTV.


Multicast assumes you are going to have lots of people watching the
same stream at the same time..



The percentage bandwidth saving for multicast compared to unicast is:

% bandwidth saving = 100 * (n - 1) / n

where n is the number of users. Just for 10 users you get 90% bandwidth
saving, for 100 you get 99%, for 1000 you get 99.9% and so on.


rather limiting for interactive
services. Good for broadcast TV but isn't that what the TV network's
for?



Multicast allows you to watch TV on a computer where you don't have a TV
set, and it's going to provide higher audio quality than DAB does.


--
Steve - www.digitalradiotech.co.uk - Digital Radio News & Info

The adoption of DAB was the most incompetent technical
decision ever made in the history of UK broadcasting:
http://www.digitalradiotech.co.uk/da...ion_of_dab.htm


  #8  
Old March 17th 08, 12:53 PM posted to uk.telecom.broadband
DAB sounds worse than FM
external usenet poster
 
Posts: 138
Default Multicast on 21CN

[email protected] wrote:
"DAB sounds worse than FM" [email protected] wrote in message
...
The first article on

http://www.samknows.com/broadband/

says at the bottom:

"The afternoon was wrapped up with a proof of concept demonstration
of video content distribution in the 21CN network. Using Assured
Rate QoS, BT showed how content could be distributed from the core,
from one of their 20 aggregation points or from the MSANs themselves
(which will be present in all exchanges in the UK). Distribution at
this level is made possible by using multicast, which is not
available on the current BT IPStream product range."


Demonstrated that to BT more than three years ago!


Could someone say whether what BT is doing will fix the problem
PlusNet describes on its blog entry below (I think it does, because
it says that multicast can be distributed from the different levels
of the 21CN, and PlusNet says that they want it split further down
the line):


The system I demonstrated could split the multicast down to the DSLAM
level.. I see no reason why BT can't do that as their exist DSLAMS
can with little modification if any.


http://community.plus.net/blog/2008/...t-of-ipstream/

"The same thing applies with multicast. Multicast can be used to more
efficiently distribute content. A number of customers wanted to
watch the same video stream then using multicast rather than there
being one stream per customer between the content provider and the
end user, where the network paths are the same there only needs to
be one stream. At the moment on IPStream that would mean that if you
were watching a multicast stream there would only need to be one
stream between the content provider and the ISP's network and it
splits into multiple feeds at central pipes. Which of course is the major
problem with using multicast at the
moment, the only cost saving to the ISP is the transit and/or
peering costs, which as we've seen above may not represent any real
savings or at best only a tiny reduction because you still have one
stream per customer going across the central pipes.

For multicast to be successful in the UK the stream must be split
further down the line, preferably at the BT PoP but at the very
least at the local exchanges. This is something we might see as part
of BT's 21st Century Network upgrades which are taking place over
the next few years."


BT could do it now.. its a case of who is going to pay.
If BT do multicast in the DSLAM then the ISPs are getting something
for nothing.
I remember the time when BT left routing on so stuff on the BT network
didn't transit the ISPs at all.. what did the ISPs do.. setup VPNs
and stuff like that to avoid their pipes and hence the charges.. BT
stopped this by forcing all the data up the ISPs pipe by
encapsulating it early on and putting it in tunnels to the ISP.


One option talked about was adding storage in the DSLAM to buffer
video streams for interactive playback.. ATM you have to go back to
the central server which limits the number of customers per DSLAM
that can have interactive video.. buffering it takes advantage of the
fact that many will be watching the same football match or eastenders
so you can get more customers doing interactive.



I don't think BT would have demonstrated video over multicast on the 21CN to
journalists last week if they weren't going to use it.

There's also the competition element, because Virgin Media will be adding
support for multicast at the same time as it launches its 50 Mbps broadband
package, and Tiscali's network is designed to support multicast. That's 2
out of the 4 biggest ISPs supporting it, and the other LLU ISPs could
support it as well if they wanted to.


--
Steve - www.digitalradiotech.co.uk - Digital Radio News & Info

The adoption of DAB was the most incompetent technical
decision ever made in the history of UK broadcasting:
http://www.digitalradiotech.co.uk/da...ion_of_dab.htm


  #9  
Old March 17th 08, 01:04 PM posted to uk.telecom.broadband
[email protected]
external usenet poster
 
Posts: 735
Default Multicast on 21CN



"DAB sounds worse than FM" [email protected] wrote in message
...
[email protected] wrote:
"Mark" wrote in message
...



Multicast has to work from head-end (wherever that is) through to
the user (a set-top box for example) in order to save aggregation
network bandwidth for applications like IPTV.


Multicast assumes you are going to have lots of people watching the
same stream at the same time..



The percentage bandwidth saving for multicast compared to unicast is:

% bandwidth saving = 100 * (n - 1) / n

where n is the number of users. Just for 10 users you get 90% bandwidth
saving, for 100 you get 99%, for 1000 you get 99.9% and so on.


So on a typical DSLAM with 600 users you need a program several of them want
to watch to do multicast at the DSLAM.



rather limiting for interactive
services. Good for broadcast TV but isn't that what the TV network's
for?



Multicast allows you to watch TV on a computer where you don't have a TV
set,


Really!?

and it's going to provide higher audio quality than DAB does.


Why should it, everyone is happy with Dab quality. ;-)



  #10  
Old March 17th 08, 01:30 PM posted to uk.telecom.broadband
DAB sounds worse than FM
external usenet poster
 
Posts: 138
Default Multicast on 21CN

[email protected] wrote:
"DAB sounds worse than FM" [email protected] wrote in message
...
[email protected] wrote:
"Mark" wrote in message
...



Multicast has to work from head-end (wherever that is) through to
the user (a set-top box for example) in order to save aggregation
network bandwidth for applications like IPTV.


Multicast assumes you are going to have lots of people watching the
same stream at the same time..



The percentage bandwidth saving for multicast compared to unicast is:

% bandwidth saving = 100 * (n - 1) / n

where n is the number of users. Just for 10 users you get 90%
bandwidth saving, for 100 you get 99%, for 1000 you get 99.9% and so
on.


So on a typical DSLAM with 600 users you need a program several of
them want to watch to do multicast at the DSLAM.



What, so that's the only place where they can save bandwidth, is it?


and it's going to provide higher audio quality than DAB does.


Why should it, everyone is happy with Dab quality. ;-)



Yeah, everyone's over the moon with DAB, that's why the sales are doing so
well despite the BBC advertising the ******** off it on TV, and there
haven't been any national station closures recently, and GCap didn't call it
"not economically feasible" and GCap didn't say that they wanted to pull out
of DAB completely if it weren't for some draconian legislation that would
screw their entire business up if they did, and GCap didn't say that DAB
provided lower quality than FM, and it won't take about 30 years to switch
off FM - it's just so good in every imaginable way. In fact it's probably
been the biggest success story in the history of the world ever.

And as for whether multicast will provide higher quality than DAB:

http://support.bbc.co.uk/multicast/streams.html

BBC: 128 kbps AAC
commercial radio: 128 or 192 kbps WMA

DAB: 128 kbps with the 1980s-vintage ridiculously inefficient MP2 codec

I rest my case.


--
Steve - www.digitalradiotech.co.uk - Digital Radio News & Info

The adoption of DAB was the most incompetent technical
decision ever made in the history of UK broadcasting:
http://www.digitalradiotech.co.uk/da...ion_of_dab.htm


 




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