nanog mailing list archives

RE: Is anyone actually USING IP QoS?


From: "Alex P. Rudnev" <alex () Relcom EU net>
Date: Tue, 15 Jun 1999 13:43:32 +0400 (MSD)


// Sorry, if it's not for nanog forum, I can drop it's address from this 
// discussion.

Alex, steve:

I know this thread is effectively dead, but I'm just catching up and enjoyed
the discussion very much. It's NANOG so it isn't surprising there was little
discussion of the edge of the networks.

No one mentioned critical other functions for multicast and QoS: data
distribution and interactive services. The growth in broadband is putting
new services (and telephone is the simpliest) on the edge of the network.
Data distribution is a model starburst is working on. I think the demand for
it will grow exponentially. 

As the broadband world grows there are real oportunities for interactive
content placed near the edge of the network. This can not be centrally
placed because of latency requirements for interactivity. The architecture
requires 1000s of servers with pratically identical data on them. It's much
like a proxy pre-fetching data. The problems is there is lots of it
(100-500G). Multi-cast on public or private net is the logical way to do get
the data there.
You areright about multimedia, but I am not sure about multicast. 
Russions are saying - if you see the banner _elebhant_ on the cell with 
the monkey in the zoo - don't believe to trhe banner.

Just there. Multicasting is the beautiful idea, nice banner. But look on 
the real world. There is MULTIMEDIA ALREADY - I can get CNN TV, I can get 
different music, I can look on the shattle lanch in real time - withouth 
multicasting. There is already EXISTING MULTIMEDIA in the network - 
RealVideo and StreamVideo/on/demand.

Not I have a question. No doubt, if 1000 customers ask RV stream from the 
CNN, the network fail down (or exactly server refuse to do it). This mean 
_this data have to be REPLICATED on the FLY_. 

There is a few different ways to do such replication. One way is 
MULTICASTING. It was developed for the LAN networks (because there is not 
other way to replicate data over the ethernet) and it's the only way to 
get multicast in the LAN if you need strong replication. But in real 
life, LAN network are not bottlechecks for this multimedia - if all 
RELCOM's employees ask RV CNN at once, our LAN networks can hold this 
traffic withouth big problems (128Kbit * 100 = 12,8Mbit - less than 1 
100BaseTX ethernet!). 

The other way is CACHING. Caching on the fly or caching with the short 
time to live.

There is two differences between this ways. Multicasting need another 
routing scheme, another address scheme, it's really ONE ANOTHER network. 
Caching need... no changes for the customer, just catch request on the 
fly (as WWW CACHE ENGINE by CISCO do for the WWW requests) and CACHE data 
on the fly). 

Now compare. One scheme need one another set of aggreements, one another 
set of configurations, etc etc... It's the only way for the DENSE 
MULTIMEDIA (if you need TV for the 1000 customers at one LAN at once, for 
example). Another way need one more protocol (such as WWW-CACHE-CONTROL 
protocol by CISCO, sorry I don't remember RFC number for it) but for some 
MultiMedia requests (RealVideo and StreamVideo are enougph for now), no 
aggreements, no additional configurations schemas, no changes for the 
customers and/or service providers. Guess what's better.

And in real live, we have not multicast in the Internet. We have some 
SHOWS, but use RVplayer or other _request and send_ systems filled up by 
the information and music. And if someone propose effective cache engine 
for this streams - he'll be winner, not multicasting.

Of course, no one prevent this cache engine from doing multicasting 
locally.

What's about QoS - first, you need something simple oer the whole 
Internet. Then you can speak about RSVP and so on - if don't WDM kill it 
for this future time.

Alex.
-----


As these new services are offered the need for QoS in the last mile will be
more critical. Some of these apps require minimal latency or strict packet
order. There is a strong future for QoS, but edge networks will require it
much more than the Internet.

I work for one of the new interactive companies. The lack of good tools and
protocols is keeping me up at night.

doug

douglas o'flaherty
dir ops & support
arepa.com



-----Original Message-----
From: Alex P. Rudnev [mailto:alex () Relcom EU net]
Sent: Tuesday, May 18, 1999 5:17 AM
To: Steve Riley (MCS)
Cc: nanog () merit edu
Subject: RE: Is anyone actually USING IP QoS?



I must agree and disagree. RSVP is dead protocol - it's enougph to 
imagine how different ISP can negotoate about RSVP service, and (in 
addition) read RSVP protocol itself...

On the other hand, why don't provide QoS in the non-overbooked network. 
It's not difficult to install PRECEDENCE queue-control, just as negotiate 
about some classes of service, to prevent short network bursts from 
disturbing multimedia streams.

I'd like to ask one more question. Multicast, 

If we project multimedia services from the scratsch, you have a few 
different choices. For example, you have RealVideo server. I ask you 
abgour RV stream. Ok, you send packets with DST=MY_ADDRESS.

Then someone else send second request. Why (WHY) can't RV server add 
second DST address into the packet? Why can't you use the same, unicast, 
address space for multicast services.

I mean - first way was (was) to use existing address space for multicast 
multimedia, and add some mechanism (such as replicators) to hide the 
mechanisms from the end user. No one bother if some RV-CACHE server catch 
his request and use his own replicator to organise multidemia stream.

Second way was choosen - to use another address space for the multimedia 
multicasting. Result - you see - Internet have not (HAVE NOT) multimedia 
multicast at all. No, some ISP have internal multicast networks, but not 
more. If I ask CNN abour RV live stream, and you ask the same, be sure - 
the server send just 2 different packets - one for you and one for me...

And this is very serious obstacle against multimedia services in the 
Internet. Not QoS (through QoS prevent using existing public networks 
from the commercial telephony), but tjis absence of mukticasting in the 
Internet.



On Mon, 17 May 1999, Steve Riley (MCS) wrote:

Date: Mon, 17 May 1999 14:04:37 -0700
From: Steve Riley (MCS) <steriley () microsoft com>
To: nanog () merit edu
Subject: RE: Is anyone actually USING IP QoS?


Nice to see that I'm not the only one believing in the foolishness of QoS
hype. Bandwidth is essentially free, and will always be cheaper than QoS.
And since in the end nearly all decisions are based on economics, it
should
be apparent which is the more logical decision.

Allow me to point you to an interesting paper called "Rise of the Stupid
Network." Many of you here may have already seen this. It was written back
in 1997 by David Isenberg, then a reasearcher at AT&T Labs (Isenberg is
now
an independent consultant). His paper profoundly changed my views on QoS
and
made me realize that networks perform best when we limit how smart they
get
and ensure that networks focus on transport only. I urge everyone to read
it.

Paper: http://www.rageboy.com/stupidnet.html
Isenberg's site: http://www.isen.com/

_________________________________________________________
Steve Riley
Microsoft Telecommunications Practice in Denver, Colorado
    email: mailto:steriley () microsoft com
    call: +1 303 521-4129 (cellular)
    page: +1 888 440-6249 or mailto:4406249 () skytel com
Applying computer technology is simply finding the right wrench to pound
in
the correct screw.



-----Original Message-----
From: Vadim Antonov [mailto:avg () kotovnik com]
Sent: Monday, May 17, 1999 12:28 PM
To: nanog () merit edu; pete () kruckenberg com
Subject: Re: Is anyone actually USING IP QoS?


Yep.  Altough not _all_ QoS schemes are broken-as-designed.  The
most trivial per-packet priority combined with ingress
priority mix shaping works.  Ths idea of end-to-end
whatever reservations or guarantees is usually propounded
by people who either neglected their CS courses or those
who are trying to sell it.

Yep.  The biggest QoS secret is that nobody actually needs
it.  Bandwidth is cheap and is growing cheaper.  The
manpower needed to deploy and maintain QoS is getting
more and more expensive.

--vadim



Aleksei Roudnev, Network Operations Center, Relcom, Moscow
(+7 095) 194-19-95 (Network Operations Center Hot Line),(+7 095) 230-41-41,
N 13729 (pager)
(+7 095) 196-72-12 (Support), (+7 095) 194-33-28 (Fax)



Aleksei Roudnev, Network Operations Center, Relcom, Moscow
(+7 095) 194-19-95 (Network Operations Center Hot Line),(+7 095) 230-41-41, N 13729 (pager)
(+7 095) 196-72-12 (Support), (+7 095) 194-33-28 (Fax)




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