Subject: RE: [Capwap] Comments on draft-ietf-capwap-arch-03.txt

From: "Pat R. Calhoun" <[email-masked]>
Date: Mon, 12 Jul 2004 21:13:51 -0700

But I would equally argue that a remote MAC causes *all* traffic to traverse the network from the AP to the AC (because the AP is really dumb). One of the benefits of Split MAC is that you have the ability to "protect" network resources by being able to apply specific filters at the edge. For example, if you have an encrypted channel, and you are capable of decrypting packets at the edge, you would further protect the network by ensuring that only properly encrypted packets enter the wired network.

So if unnecessary burden of the wired network is considered a management burden, then I would argue that Split MAC increases manageability.

PatC
-----Original Message-----
From: Cheng Hong [mailto:[email-masked]]
Sent: Mon 7/12/2004 9:00 PM
To: Pat R. Calhoun; [email-masked]; [email-masked]
Subject: RE: [Capwap] Comments on draft-ietf-capwap-arch-03.txt
 
This really depends on how you define MANAGEABILITY. If the decrease in
signaling message is counted as increase in managemeability, it is obivous
that that moving the whole MAC to AC will simplify the protocol messages
used between AC and AP (at least less messags). 
 
cheers
 
Cheng 

-----Original Message-----
From: Pat R. Calhoun [mailto:[email-masked]] 
Sent: Tuesday, July 13, 2004 11:55 AM
To: Cheng Hong; [email-masked]; [email-masked]
Subject: RE: [Capwap] Comments on draft-ietf-capwap-arch-03.txt

Could I perhaps ask you to provide me with concrete data that proves this is
the case? I have plenty of data that proves that the centralized approach
provides much better manageability. However, there is nothing in my data
that shows that where some of the finer components of the MAC terminate
increase (or decrease) manageability.

PatC

-----Original Message-----
From: Cheng Hong [mailto:[email-masked]]
Sent: Mon 7/12/2004 8:50 PM
To: Pat R. Calhoun; [email-masked]; [email-masked]
Subject: RE: [Capwap] Comments on draft-ietf-capwap-arch-03.txt

As for the remote vs split, when we apply the same logic here, when the
degree of centralization increases, more info will be available at the AC.
Thus, the manageability will be better.

But, of course the centralization also brings other issues, and therefore
the degree of split should be a trade off result of different aspects.

cheers

Cheng Hong

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf
Of Pat R. Calhoun
Sent: Tuesday, July 13, 2004 11:35 AM
To: Cheng Hong; [email-masked]; [email-masked]
Subject: RE: [Capwap] Comments on draft-ietf-capwap-arch-03.txt

I'm obviously not arguing that centralization is better... my point was that
the sentence that remote vs. split provides better manageability. I do not
agree with that sentence, and the document also does not provide any
supporting data to prove the point.

PatC
-----Original Message-----
From: Cheng Hong [mailto:[email-masked]]
Sent: Mon 7/12/2004 8:28 PM
To: Pat R. Calhoun; [email-masked]; [email-masked]
Subject: RE: [Capwap] Comments on draft-ietf-capwap-arch-03.txt

Hi Pat,

I think the point is that with a centralized arch. you have more information
about the network, i.e. at the centralized controller you have a overall
view of the network instead of just the AP point of view. Therefore, more
"value added" service could be provided. One simple example is that the SME
could make better decisions with info from several AP.

cheers

Cheng Hong

-----Original Message-----
From: [email-masked] [mailto:[email-masked]] On Behalf
Of Pat R. Calhoun
Sent: Tuesday, July 13, 2004 10:29 AM
To: [email-masked]; [email-masked]
Subject: RE: [Capwap] Comments on draft-ietf-capwap-arch-03.txt

> 7. Section 4.5. Could the authors please explain how they came to the
conclusion that Remote MAC "improves
> WTP manageability"?

If I can proffer an explanation; the characteristics of Remote MAC
follow from those of the Split MAC architecture. The Split MAC improves
manageability over basic autonomous WTPs by centralizing some control
aspects; Remote MAC goes further by centralizing 'all' aspects of the
MAC. So the entire MAC processing is consolidated while the WTPs become
extremely light devices.

<PRC> But one of the "advantages" of a centralized architecture, is that the
WTP look like "local interfaces", and are managed as such. Whether one
implements
remote or split MAC does not really change how one would manage such a
network -
so it's really down to implementation details.

<PRC> So as a consequence I disagree with the assumption (and statement)
made
in the document

PatC

---

From: "Cheng Hong" <[email-masked]>
Date: Tue, 13 Jul 2004 12:24:33 +0800

Well. That is a valid point. But would that be equally a burden with the
split MAC where you need to put in extra efforts to manage the filter and
the encryption at the edge?  And, with a proper network design (not
management), we don't need to care about the "burden" of traffic considering
that the wireless has much lower bandwidth offered than the wired network.
 
cheers

-----Original Message-----
From: Pat R. Calhoun [mailto:[email-masked]] 
Sent: Tuesday, July 13, 2004 12:14 PM
To: Cheng Hong; [email-masked]; [email-masked]
Subject: RE: [Capwap] Comments on draft-ietf-capwap-arch-03.txt

But I would equally argue that a remote MAC causes *all* traffic to traverse
the network from the AP to the AC (because the AP is really dumb). One of
the benefits of Split MAC is that you have the ability to "protect" network
resources by being able to apply specific filters at the edge. For example,
if you have an encrypted channel, and you are capable of decrypting packets
at the edge, you would further protect the network by ensuring that only
properly encrypted packets enter the wired network.

So if unnecessary burden of the wired network is considered a management
burden, then I would argue that Split MAC increases manageability.

PatC
-----Original Message-----
From: Cheng Hong [mailto:[email-masked]]
Sent: Mon 7/12/2004 9:00 PM
To: Pat R. Calhoun; [email-masked]; [email-masked]
Subject: RE: [Capwap] Comments on draft-ietf-capwap-arch-03.txt

cheers

Cheng

-----Original Message-----
From: Pat R. Calhoun [mailto:[email-masked]]
Sent: Tuesday, July 13, 2004 11:55 AM
To: Cheng Hong; [email-masked]; [email-masked]
Subject: RE: [Capwap] Comments on draft-ietf-capwap-arch-03.txt

PatC

-----Original Message-----
From: Cheng Hong [mailto:[email-masked]]
Sent: Mon 7/12/2004 8:50 PM
To: Pat R. Calhoun; [email-masked]; [email-masked]
Subject: RE: [Capwap] Comments on draft-ietf-capwap-arch-03.txt

cheers

Cheng Hong

-----Original Message-----

PatC
-----Original Message-----
From: Cheng Hong [mailto:[email-masked]]
Sent: Mon 7/12/2004 8:28 PM
To: Pat R. Calhoun; [email-masked]; [email-masked]
Subject: RE: [Capwap] Comments on draft-ietf-capwap-arch-03.txt

Hi Pat,

cheers

Cheng Hong

-----Original Message-----

PatC