Subject: Re: [PCN] 2nd charter text update

From: Lars Eggert <[email-masked]>
Date: Thu, 1 Feb 2007 11:43:14 +0200

On 2007-2-1, at 1:50, ext Kwok-Ho Chan wrote:
> At 04:23 AM 1/31/2007, Lars Eggert wrote:
>> Talking about "nodes" and "paths" leaves the door open for other work
>> than the routers-within-a-single-DiffServ-domain model that we want
>> to focus the work on initially.
>
> KHC_START>
> The use of "IP packet data path" is just to make the proposed charter
> more concise.  May be it becomes too wordy in the itemized sentences,
> hence it will be OK for me if they are removed from the itemized  
> sentences.
> But I think "These mechanisms operate on the IP packet data path"  
> at the top
> is helpful to make the propose charter more clear and concise.

But they only operate on a subset of the end-to-end path, namely, the  
part that falls into the PCN-enabled DiffServ domain.

> On the topic of using the words "nodes" and/or "routers".
> I don't have a good understanding of why the word "router" must be  
> there.
> Many of today's "routers" perform "switching" instead of "routing".
> And many of today's "routers" does more than just "routing".
> Is a "blade-center" a "router"?  Part of it is a "router"?
> And does the output (behavior, mechanism documentations) of this WG  
> need to be
> implemented on a specific hardware implementation?  On a specific  
> physical box?
> IMHO, the proposed-standards documents produced by this WG should  
> indicate
> behaviors and functionality.  To promote and assure inter-operability.
> IMHO, the proposed-standards documents produced by this WG should  
> NOT dictate
> how the implementation is done, or where (which and what kind of  
> square/round physical box)
> the implementation must be done at.

Since the initial goal is to PCN-enable a DiffServ region, I agree  
that it would remove confusion if the charter used the terms from  
RFC2475. I'll take a stab at the appropriate rephrasings.

> "(3) encoding and transport of (pre-)congestion signals (replaced  
> with information)
> to the appropriate ingress routers of the network domain"
> confusing because I believe we want to specify in a standards track  
> document
> how the (pre-)congestion information is encoded (the bits and bytes  
> detail) in
> some IP header field (ECN, DSCP, etc).

This has already been rephrased in my working copy.

Lars

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---

From: "Kwok-Ho Chan" <[email-masked]>
Date: Thu, 01 Feb 2007 10:22:09 -0500

Please see my comments enclosed by KHC_START> and KHC_END>.
Thank you very much for handling the "funnel" (many of us giving you comments)!
-- Kwok --

>part that falls into the PCN-enabled DiffServ domain.

KHC_START>
Agree.  The words "IP packet data path" is intended to indicate the 
behaviors and
mechanisms we are trying to standardize are "on-path" behaviors and mechanisms.
I am not trying to say anything about subset of the end-to-end path 
or end-to-end path.
If you feel my intend is not necessary, lets give it a try on not 
having those words.
Or you can add additional clarification that "IP packet data path of 
the PCN-enabled
DiffServ domain/region".
KHC_END>

>RFC2475. I'll take a stab at the appropriate rephrasings.

KHC_START>
OK, lets give it a try.  Thanks!
KHC_END>

>This has already been rephrased in my working copy.

KHC_START>
Thanks!
KHC_END>

---

From: Tina TSOU <[email-masked]>
Date: Thu, 01 Feb 2007 19:03:37 +0100

Hi Kwok-Ho,
See in line(:

----- Original Message ----- 
From: "Kwok-Ho Chan" <[email-masked]>
To: "Lars Eggert" <[email-masked]>
Cc: <[email-masked]>
Sent: Thursday, February 01, 2007 4:22 PM
Subject: Re: [PCN] 2nd charter text update

> I am not trying to say anything about subset of the end-to-end path or 
> end-to-end path.
> If you feel my intend is not necessary, lets give it a try on not having 
> those words.
> Or you can add additional clarification that "IP packet data path of the 
> PCN-enabled
> DiffServ domain/region".
> KHC_END>
If we still only focus on routers-within-a-single-DiffServ-domain, "IP 
packet data path of the PCN-enabled DiffServ domain/region" does not reflect 
this focus.

---

From: "Kwok-Ho Chan" <[email-masked]>
Date: Thu, 01 Feb 2007 15:05:37 -0500

Tina:
You have indicated:
If we still only focus on routers-within-a-single-DiffServ-domain, 
"IP packet data path of the PCN-enabled DiffServ domain/region" does 
not reflect this focus.

Maybe it is best to put all these back into the full sentence:
These mechanisms operate on the IP packet data path of the 
PCN-enabled DiffServ domain,
with network nodes:
1) ...
2) ...

I think we agreed we want the first phase of PCN to focus on 
"within-a-single-DiffServ-domain".
And we have agreed "a-single-DiffServ-domain" can be one or more 
DiffServ-domains (hence
I added the /region, and let LarsE use the correct definition of 
domain or region).

So I have equated "within-a-single-DiffServ-domain" = "PCN-enabled 
DiffServ domain"

By your comment, I interpreted you feel this equation is not correct.
I don't understand the reasoning and will need some educating by you.
May be providing the correct wording to resolve this will help us 
reach the agreed charter.

Thanks!
-- Kwok-Ho (Chinese names normally contain both the first and middle 
name characters) --

At 01:03 PM 2/1/2007, Tina TSOU wrote:
>Hi Kwok-Ho,
>See in line(:
>
>----- Original Message ----- From: "Kwok-Ho Chan" <[email-masked]>
>>Or you can add additional clarification that "IP packet data path 
>>of the PCN-enabled
>>DiffServ domain/region".
>>KHC_END>
>If we still only focus on routers-within-a-single-DiffServ-domain, 
>"IP packet data path of the PCN-enabled DiffServ domain/region" does 
>not reflect this focus.
>>
>>

---

From: Tina TSOU <[email-masked]>
Date: Fri, 02 Feb 2007 15:19:26 +0100

Hi Kwok,
My comments were based on my discussion with LarsE.
If "a-single-DiffServ-domain" can be one or more DiffServ-domains, my 
comments are not valid.
Now, I am OK with 3rd charter text.

B. R.
Tina

----- Original Message ----- 
From: "Kwok-Ho Chan" <[email-masked]>
To: "Tina TSOU" <[email-masked]>
Cc: "Lars Eggert" <[email-masked]>; "Kwok-Ho Chan" 
<[email-masked]>; <[email-masked]>
Sent: Thursday, February 01, 2007 9:05 PM
Subject: Re: [PCN] 2nd charter text update

> packet data path of the PCN-enabled DiffServ domain/region" does not 
> reflect this focus.
>
> These mechanisms operate on the IP packet data path of the PCN-enabled 
> DiffServ domain,
> with network nodes:
> 1) ...
> 2) ...
>
> I added the /region, and let LarsE use the correct definition of domain or 
> region).
>
> May be providing the correct wording to resolve this will help us reach 
> the agreed charter.
>
> Thanks!
> -- Kwok-Ho (Chinese names normally contain both the first and middle name 
> characters) --
>
>
>>packet data path of the PCN-enabled DiffServ domain/region" does not 
>>reflect this focus.
>>>
>>>

---

From: [email-masked]
Date: Sat, 3 Feb 2007 21:02:40 -0500

> If "a-single-DiffServ-domain" can be one or more DiffServ-domains,
> my comments are not valid.

RFC 2475 is reasonably precise about this.  A diffserv (DS) domain is
"a contiguous set of nodes which operate with a common set of service
provisioning policies and PHB definitions."  A diffserv region is
"a set of contiguous DS domains which can offer differentiated
services over paths across those DS domains."

The minimum requirement on PCN is that it must work on a single
diffserv domain where edge nodes are edge nodes, interior nodes are
interior nodes, and no node is in both categories.  That is what I
see proposed as immediate work in the charter text.  In the longer
term, one can look at spanning DS domains (i.e., PCN for DS regions),
and that's what's proposed for future work in the charter text
(e.g., concatenated DiffServ domains).

On a different diffserv topic, I'm somewhat confused by Lars
Westberg's request (NB: I spelled his name right this time, and
I apologize for mangling it earlier):

> Can't we add a small text into the charter so we do not required a
> full-fledge Diff.serv edge functionality in the boundary nodes ???

RFC 2474 is the specification of what is minimally required for
Diffserv. It doesn't require all that much.  What is envisioned by
"full-fledge Diff.serv edge functionality" and what piece of it
is behind this concern?  PCN already requires the edges to be
flow-aware which is the major distinction between diffserv edge
vs. interior nodes (which are not flow-aware).

Thanks,
--David (RFC 2474 and 2475 co-author)
----------------------------------------------------
David L. Black, Senior Technologist
EMC Corporation, 176 South St., Hopkinton, MA  01748
+1 (508) 293-7953             FAX: +1 (508) 293-7786
[email-masked]        Mobile: +1 (978) 394-7754
----------------------------------------------------

---

From: Lars Westberg <[email-masked]>
Date: Mon, 05 Feb 2007 09:06:11 +0100

comments inline

> vs. interior nodes (which are not flow-aware).

In PCN-network, I am interested in scenarios, when the marking-functions 
is used together with a flexible set boundary functions ( a flexible set 
of feedback and marking aggregation).
The feedback and marking aggregation depends on the boundary nodes and 
deployment scenario.

This will probably imply an requirement on the framework document.

regards Lasse

---

From: "Geib, Ruediger" <[email-masked]>
Date: Mon, 5 Feb 2007 09:17:59 +0100

I'd also like to ask Phil Eardly for comments. He proposed to 
include work on "trusted DiffServ domains", which I'd interpret 
as referring to an architecture like CarrierA_Service_Switch 
performing per flow admission control and being connected to 
CarrierA_Transport_network by a wholesale PCN interface having 
no per flow funtionalities (note that Service/Transport 
divisions could operate separately). I'm interested in looking 
at such a scenario too. I don't want to propose an extra 
definition if architectures like the above are covered by "a 
single DS domain".

Regards,

Ruediger

|-----Original Message-----
|From: [email-masked] [mailto:[email-masked]]
|Sent: Sunday, February 04, 2007 3:03 AM
|To: [email-masked]; [email-masked]
|Cc: [email-masked]
|Subject: [PCN] PCN and Diffserv issues
|
|
|> My comments were based on my discussion with LarsE.
|> If "a-single-DiffServ-domain" can be one or more DiffServ-domains,
|> my comments are not valid.
|
|RFC 2475 is reasonably precise about this.  A diffserv (DS) domain is
|"a contiguous set of nodes which operate with a common set of service
|provisioning policies and PHB definitions."  A diffserv region is
|"a set of contiguous DS domains which can offer differentiated
|services over paths across those DS domains."
|
|The minimum requirement on PCN is that it must work on a single
|diffserv domain where edge nodes are edge nodes, interior nodes are
|interior nodes, and no node is in both categories.  That is what I
|see proposed as immediate work in the charter text.  In the longer
|term, one can look at spanning DS domains (i.e., PCN for DS regions),
|and that's what's proposed for future work in the charter text
|(e.g., concatenated DiffServ domains).
|
|On a different diffserv topic, I'm somewhat confused by Lars
|Westberg's request (NB: I spelled his name right this time, and
|I apologize for mangling it earlier):
|
|> Can't we add a small text into the charter so we do not required a
|> full-fledge Diff.serv edge functionality in the boundary nodes ???
|
|RFC 2474 is the specification of what is minimally required for
|Diffserv. It doesn't require all that much.  What is envisioned by
|"full-fledge Diff.serv edge functionality" and what piece of it
|is behind this concern?  PCN already requires the edges to be
|flow-aware which is the major distinction between diffserv edge
|vs. interior nodes (which are not flow-aware).
|
|Thanks,
|--David (RFC 2474 and 2475 co-author)
|----------------------------------------------------
|David L. Black, Senior Technologist
|EMC Corporation, 176 South St., Hopkinton, MA  01748
|+1 (508) 293-7953             FAX: +1 (508) 293-7786
[email-masked]        Mobile: +1 (978) 394-7754
|----------------------------------------------------
|
|_______________________________________________
|PCN mailing list
[email-masked]
|https://www1.ietf.org/mailman/listinfo/pcn
|

---

From: <[email-masked]>
Date: Mon, 5 Feb 2007 11:31:00 -0000

If I understand correctly I think this is included OK.

> -----Original Message-----
> From: Geib, Ruediger [mailto:[email-masked]]
> Sent: 05 February 2007 08:18
> To: [email-masked]
> Cc: [email-masked]
> Subject: RE: [PCN] PCN and Diffserv issues
>