Subject: RE: Congestion avoidance Re: [Ieprep] draft-ietf-ieprep-framework -02.txt

From: "Nguyen, An" <[email-masked]>
Date: Fri, 1 Nov 2002 17:41:41 -0500

Kimberly,

There is no problem now with the core, I agree. But the picture might look
different later on. 

Are you saying if there is any problem with the access node, the network
operators will solve the problem by throwing more equipment at it? The
question is that how dynamic is that bandwidth increasing in response to
congestions?

An

-----Original Message-----
From: King, Kimberly S. [mailto:[email-masked]]
Sent: Friday, November 01, 2002 3:40 PM
To: 'Nguyen, An'
Cc: [email-masked]; [email-masked]
Subject: RE: Congestion avoidance Re: [Ieprep]
draft-ietf-ieprep-framework-02.txt

An,

>By the 
> way, how are
> you doing it in your network to accommodate emergency traffic when
> congestions occur at the access nodes (not the distribution 
> or the core)?
> How about priority queuing or weighted fair  queuing ?

Bill told me about his VoIP system last year.  I'm sure he will correct me
if I have got  something wrong or things have changed.  But, he said that
QoS was not an issue.  Since the core was OC48s and OC192s running at 20%
utilization or less, there was lots of capacity.  The system was running
mostly in developed country ISPs.  

Access nodes, if I understand what you mean, don't pose a problem because
this VoIP system serves ISP NOC operators.  So they could increase their
bandwidth to the exchange if that turned out to be a problem.  It didn't
sound like it was one.

Kimberly
_______________________________________________
Ieprep mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/ieprep

---

From: RJ Atkinson <[email-masked]>
Date: Mon, 4 Nov 2002 17:23:29 -0500

> There is no problem now with the core, I agree. But the picture might 

Things might vary.  So far it has been a lot cheaper to throw bandwidth
at the problem than to increase the operational costs (deploying 
ANYTHING
extra increases operational costs; so QoS is not zero cost to deploy).

And there are tremendous amounts of spare fibre capacity today in most 
places
with significant IP deployment -- and that fibre is often lower cost to
purchase now than it was to originally build out.  So capacity is 
getting
cheaper, not more expensive, even today.

> question is that how dynamic is that bandwidth increasing in response 

The speed of the access link is normally controlled by the customer
behind that link.  This is normally a commercial/economic decision
by that customer.  For example, "do I pay the $ N+M for a T3 uplink
to ISP A or do I pay $N for a T1 uplink to ISP A ?"  And when I say
customer, that might be a home, a small office, a large office,
a campus, or a private network (e.g. GE's corporate WAN).

Inter-provider connectivity is increasingly performed via private
peering, not at exchange points.  Terminology varies, but I would
not call an exchange point an "access link".  And the exchange
points have mostly migrated to use 1 Gbps Ethernet and nearly
always on non-blocking switch fabrics [1].  I expect 10 GigE to
start deployment in exchange points during 2003.

Ran
[email-masked]

[1] The old DEC GigaSwitch FDDI switches had a blocking switch fabric,
which caused significant operational grief throughout their lifetime.
Operators learn quickly -- so they always ask for non-blocking switches
for use in the exchange point situation.

---

From: Rex Buddenberg <[email-masked]>
Date: 04 Nov 2002 14:44:52 -0800

> cheaper, not more expensive, even today.

Ran, you're right regarding the core of the network.  We've been
overprovisioning rather than controlling QoS almost universally for most
of the life of the Internet.

But the scenario we need to account for here is that the emergency
customers who need the priority services are at least a couple hops away
from the core.  IMHO, the best scenario is when one end of a connection
is on a wireless net at the edge of the internet fabric.  The second
best scenario is where we have a radio-WAN somewhere in the interior of
the network that is at least a router away from the customers (the
reason for the radio-WAN is either reach to mobile platforms or as
bridge across damaged connectivity, suit yourself).  It's network
plumbing that includes these features that we need to be engineering
for.

---

From: Bill Woodcock <[email-masked]>
Date: Wed, 6 Nov 2002 09:51:07 -0800 (PST)

> question is that how dynamic is that bandwidth increasing in response to

Not exactly...  If there's a congestion problem within a customer network,
ISPs are not able to resolve that problem.  ISPs cannot autonomously
increase the capacity of a customer tail-circuit, since the customer-owned
CPE must be simultaneously upgraded, nor can ISPs implement QoS on
customer-owned devices, even if it were the case that QoS were beneficial.

Fortunately, none of that is an issue, since the demands which VoIP places
on the network are so small.

                                -Bill