Some thoughts:
-
Coast-to-coast “guaranteed latency” seems too low in most cases that I’ve seen. Not calling CEOs and marketers liars but the real world doesn’t seem to do as well as the promises. As VOIP takes off “local” IP exchanges will continue/increase in importance because people won’t tolerate high latency. What percentage of your phone calls are local?
-
Yes, we do various kinds of video over Internet2. Guess what? Packet loss is very important. Fewer hops mean fewer lost packets. Local exchanges, if there were lots of them with lots of peering reduces the theoretical number of hops. Who will most of the videoconferences involve in the future — I think mostly people who see each other face-to-face periodically. Leading this are telework and telemed. Broadband is getting to the point that people will want to call up their doc/clinic rather than jump in the car just to be told to go home and go to bed, and get exposed to someone who has a contagious disease. Nursing homes, assisted living facilities, emergency rooms in mall towns should be key targets for this technology.
-
While we’re on the topic of local video, what happens when television migrates to IP networks? Seems like the “local” news should want to originate somewhere close. Most of our local TV and radio stations are part of chain today and their corporate headquarters have decided to host their web site at a central location without even worrying about Akamai or other local caching.
-
Unfortunately, these applications do not work with today’s local broadband networks — one reason being the lack of local interconnection. People have quit believing the Radio Shack ads. We have the technology to make these applications work if we’d stop arguing that no one wants to use them. Of course no one wants to use them — they know they won’t work!
David Diaz techlist@smoton.net 11/14/02 05:52PM >>>
Voice of reason…
The only possible reason I can think of is if these data networks
replace the present voice infrastructure. Think about it, if we
really all do replace our phones with some video screen like in the
movies, then yes, most of those calls stay local within the cities.
Mom calling son etc etc
So we can think of these “peering centers” as replacements for the
5-10 COs in most average cities.
Otherwise what apps require such dense peering.
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Some thoughts:
- Coast-to-coast “guaranteed latency” seems too low in most cases that I’ve seen. Not calling CEOs and marketers liars but the real world doesn’t seem to do as well as the promises. As VOIP takes off “local” IP exchanges will continue/increase in importance because people won’t tolerate high latency. What percentage of your phone calls are local?
Well the bingo latency number used a lot in voice is 50ms. Im simplifing without getting into all the details, but that’s an important number. As far as VoIP goes, I think higher latency is ok, it’s more important to have “consistent” latency. Fluctuating latency really affects VoIP more then a higher consistent latency. There are a lot of people doing VoIP and traditional voice on satellites and the latency there is huge. Coast to coast latency on a good network is ~45 - 65ms depending on which customers you talk to. Most phone calls are local as I mentioned in an earlier post so I do agree with you here that it would be a replacement for the traditional CO.
- Yes, we do various kinds of video over Internet2. Guess what? Packet loss is very important. Fewer hops mean fewer lost packets. Local exchanges, if there were lots of them with lots of peering reduces the theoretical number of hops. Who will most of the videoconferences involve in the future � I think mostly people who see each other face-to-face periodically. Leading this are telework and telemed. Broadband is getting to the point that people will want to call up their doc/clinic rather than jump in the car just to be told to go home and go to bed, and get exposed to someone who has a contagious disease. Nursing homes, assisted living facilities, emergency rooms in mall towns should be key targets for this technology.
Fewer hops = less packet loss? There has been a lot of discussion on the list about that. I still dont see it although it does push latency up a bit. Truth is that there are a lot of tunnels or express routes build in, so we arent seeing all the hops nowadays. I think that’s more for sales and marketing as people keep judging networks by hops in a traceroute.
- While we’re on the topic of local video, what happens when television migrates to IP networks? Seems like the “local” news should want to originate somewhere close. Most of our local TV and radio stations are part of chain today and their corporate headquarters have decided to host their web site at a central location without even worrying about Akamai or other local caching.
An IP backbone is a bad place for live TV. Delayed or on demand tv yes. Live tv plays to the benefits of One to Many broadcast ability of satellite as Doug Humphrey will tell you. So a feed from a DSS dish into your local cache would work well. It still can be done at a per city peering point to better feed the broadband users. Its the simplest solution probably although I know someone will mention multicast here…
Actually I find it interesting that the movie industry is taking the initiative and putting up a website to do streaming movies for free to users. They are trying to learn from the mistakes of the music industry. Perhaps this is the killer app since it’s one to one transmission over the IP backbone. It would be ironic if hollywood trying to avoid video theft drove peering and IP growth… interesting world we live in.
Have a nice weekend.
dd
- Unfortunately, these applications do not work with today’s local broadband networks � one reason being the lack of local interconnection. People have quit believing the Radio Shack ads. We have the technology to make these applications work if we’d stop arguing that no one wants to use them. Of course no one wants to use them � they know they won’t work!
David Diaz techlist@smoton.net 11/14/02 05:52PM >>>
Voice of reason…
The only possible reason I can think of is if these data networks
replace the present voice infrastructure. Think about it, if we
really all do replace our phones with some video screen like in the
movies, then yes, most of those calls stay local within the cities.
Mom calling son etc etc
So we can think of these “peering centers” as replacements for the
5-10 COs in most average cities.
Otherwise what apps require such dense peering.
Some thoughts:
- Coast-to-coast "guaranteed latency" seems too low in most cases that
I've seen. Not calling CEOs and marketers liars but the real world
doesn't seem to do as well as the promises. As VOIP takes off "local"
IP exchanges will continue/increase in importance because people won't
tolerate high latency. What percentage of your phone calls are local?
Who cares? Voice is only 56 or so kbps. Just give it absolute queueing
priority, and suddenly you have negligible jitter...
- Yes, we do various kinds of video over Internet2.
People are doing various kinds of video over Internet 1; works fine.
- While we're on the topic of local video, what happens when
television migrates to IP networks?
Why should it? There's a cheap, ubiquitous, widely deployed broadcasting
medium already. I never understood network integration for the sake of
network integration.
In any case, TV (of all things) does not have problems with latency or
jitter below 10s of seconds. All TV content is pre-packaged.
--vadim
- While we're on the topic of local video, what happens when
television migrates to IP networks?
Why should it? There's a cheap, ubiquitous, widely deployed broadcasting medium already. I never understood network integration for the sake of network integration.
That medium only works for large audiences. It does not address geographically
large sparse audiences at all.
In any case, TV (of all things) does not have problems with latency or
jitter below 10s of seconds. All TV content is pre-packaged.
Live events and interactive show's are not. In some cases you start to suffer if your
latency goes to multiple-seconds range. That's quite rare anyway, >500ms
network latency is quite rare and add few hundred codec and de-jitter latency and
you'll find that excessive jitter is your enemy, not the latency itself.
Pete
>In any case, TV (of all things) does not have problems with latency or
>jitter below 10s of seconds. All TV content is pre-packaged.
Live events and interactive show's are not.
"Live" events are typically delayed by a minute or so to give time to
editors to decide on course of action if something goes wrong with "live"
feed. In any case, nobody cares about another half-minute of delay.
The same pretty much goes for "interactive" shows - which all have
interaction loops of minutes, not sub-second response which is hard to do
over the regular Internet.
In some cases you start to suffer if your latency goes to
multiple-seconds range. That's quite rare anyway, >500ms network
latency is quite rare and add few hundred codec and de-jitter latency
and you'll find that excessive jitter is your enemy, not the latency
itself.
Excessive jitter is easily converted into latency by having bigger buffers
at the receiving end.
So far, the only mass applications which have real need to have low
latency are telephony (including video kind) and on-line gaming. Those
are relatively low-bandwidth, and so don't contribute much to long-haul
traffic.
Of course, hauling bits over long-distance circuits costs more than doing
the same over local exchanges - but the current routing technology makes
having hundreds of local exchanges somewhat infeasible.
--vadim
> - While we're on the topic of local video, what happens when
> television migrates to IP networks?
Why should it? There's a cheap, ubiquitous, widely deployed broadcasting
medium already. I never understood network integration for the sake of
network integration.
Primarily because it is not interactive.
The ones that are interactive are not ubiquotous.
-- Alex Rubenstein, AR97, K2AHR, alex@nac.net, latency, Al Reuben --
-- Net Access Corporation, 800-NET-ME-36, http://www.nac.net --
speaking of paix, for those of you in atlanta (ietf) this week, i'm
going to do a couple of site walkthroughs. send me e-mail if interested.
In the 1990's the MAEs and Gigaswitches would give us an unscheduled
failure of a major exchange point on a regular basis, which let us
demostrate our disaster recovery capabilities. With the improved
reliability, i.e. the PAIXes haven't had a catastrophic failure, we
haven't had as many opportunities to demonstrate how well we can handle
a disaster at those locations.
Without creating an actual disaster, what if all the providers turned off
their BGP sessions with other providers at a PAIX (or Equinix or LINX or
where ever), both through the shared switch and private point-to-point
links, for an hour. More than likely no one would notice, but then
we would have some hard data. Individually providers have tested parts of
their own network, but I haven't heard of any coordinated efforts to test
recovery across all the service providers in a particular location.
The main problem will be coordination.. you need to get all providers to do this
in a tight slot of only one hour. And to make this a good test you need to
ensure that all the major players take part more so than the smaller ISPs. From
what I've seen its difficult enough to get ISPs to make config changes within a
window of a couple of weeks so you're gonna have a problem pulling this
together!
Also from what I've seen I'll think you'll find things have changed, reduced
budgets have forced compromises on redundancy and shutting down an exchange will
have a noticable impact to users in the region... you could argue this is all
the more reason to conduct these exercises!
Steve
July 31st 2002, this list:
2121 Jul 31 Herb Leong ( 4) Is the PAIX Palo Alto taking a dump?
How quickly we forget. 
The usual response was it only affected the public exchange fabric, not
any private point-to-point circuits between providers through the same
facility.
But if we're going to compare this to MAE Gigaswitch failures, shouldn't
we be talking apples to apples and oranges to oranges?
In this case, the MAE was a banana: Worldcom always officially discouraged
private interconnects among colocated routers.
Steve
There was a major power outage in Amsterdam on November 6th, which took
down the power at 2 major housing locations (Nikhef and SARA), which
house the original 2 AMS-IX sites, and lots of routers.
Even though Amsterdam (and AMS-IX) is a major hub for european
connections, most worked as usual, though some Dutch destinations has
higher than normal delay and packet loss.
/Jesper
No. The world has changed. If people are buying tangerines and grapefruit
now, that's what we should be talking about, not apples and oranges. If
most of today's Internet exchange is via private connections, those are
the connections we should be looking at.
The fine folks at Caimis and Caida have done some analysis, and identified
the nodes which make up the "core" of the Internet. They've also
identified the most connected "core" nodes. The good news is the network
doesn't go non-linear until more than 25% of the nodes are removed.
Thus spake "Jere Retzer" <retzerj@ohsu.edu>
- Coast-to-coast "guaranteed latency" seems too low in most cases that I've
seen. Not calling CEOs and marketers liars but the real world doesn't seem
to do as well as the promises.
Someone in the engineering group of a promising local ISP once told me their
billing and capacity planning model was designed for them to fail every customer
SLA and still turn a profit. Interpret that how you wish.
As VOIP takes off "local" IP exchanges will continue/increase in importance
because people won't tolerate high latency.
Any point in the US is within 25ms RTT (or less) of a major exchange;
eliminating this 25ms of latency will have no effect on VoIP unless you're
already near the 250ms RTT limit for other reasons.
What percentage of your phone calls are local?
Who cares? I'm billed by the airtime I consume, not by the distance my call
goes. Hawaii and the local pizza place cost me the same amount.
- Yes, we do various kinds of video over Internet2. Guess what? Packet loss
is very important. Fewer hops mean fewer lost packets.
You've been listening to the MPLS/ATM crowd too long. Congestion, not hops,
causes packet loss.
- Unfortunately, these applications do not work with today's local broadband
networks � one reason being the lack of local interconnection. People have
quit believing the Radio Shack ads. We have the technology to make these
applications work if we'd stop arguing that no one wants to use them. Of
course no one wants to use them � they know they won't work!
These apps are broken because the interested parties aren't interested. Ask any
doctor if he wants to give up physically seeing his patients -- there are laws
in most states outlawing doctors talking to patients unless they are physically
present, not to mention most doctors refuse to even digitize their records or
use Palm Pilots to look up forgotten symptoms or treatments. Blaming broadband
for the failure of your "killer apps" is not going to help.
S
Paul,
Not sure if you are currently in a position to answer this...
With the impending S&D buyout of some of PAIX's assets, do you see PAIX
Atlanta as a going concern? I know S&D owns an adjacent floor at 56
Marieta. Do you think they will hold on to both? I am curious, as my
company has a POP in PAIX Atlanta, and we are starting to do some
contigency planning.
Thanks,
Daniel Golding
My apologies. This was not intended to go out to the list.
- Dan
I agree with everything said Stephen except the part about the medical industry. There are a couple of very large companies doing views over an IP backbone down here. Radiology is very big on networking. They send your films or videos over the network to where the Radiologist is. For example one hospital owns about 6 others down here, and during off hours like weekends etc, the 5 hospitals transmit their films to where the 1 radiologist on duty is.
There are also several clinic chains where they take the films and then send them to the radiologists in another location. Some of these are really rural areas and apparently the doctors used to have to drive in on certain days, or fedex, not exactly great if it really is an emergency.
Dont know the legality, but apparently people are really doing it. Im not sure any of this needs an exchange pt though. None of it is real time yet.
Thus spake "David Diaz" <techlist@smoton.net>
I agree with everything said Stephen except the part about the
medical industry. There are a couple of very large companies doing
views over an IP backbone down here. Radiology is very big on
networking. They send your films or videos over the network to where
the Radiologist is. For example one hospital owns about 6 others
down here, and during off hours like weekends etc, the 5 hospitals
transmit their films to where the 1 radiologist on duty is.
I meant my reply to be directed only at "telemedecine", where the patient is at
home and consults their general practitioner or primary care physician via
broadband for things like the flu or a broken arm. While there's lots of talk
about this in sci-fi books, there's no sign of this making any significant
inroads today, nor does it qualify as a "killer app" for home broadband.
I do work with several medical companies who push radiology etc. around on the
back end for resource-sharing and other purposes. This is quite real today, and
is driving massive bandwidth upgrades for healthcare providers. However, I
don't think it qualifies under most people's idea of telemedecine.
S