Subject: RE: [16ng] Submission ofdraft-riegel-16ng-ip-over-eth-over-80216-00.txt

From: "Riegel, Maximilian" <[email-masked]>
Date: Tue, 20 Jun 2006 23:48:15 +0200

Erik,

Thanks for the review and sorry for mentioning 'ASN' in chapter 4.1.2.
It is a copy-and-paste mistake when adopting the text from the
specification, which we developed in the WiMAX NWG for IPoETH CS. Just
replace all occurrences of 'ASN' by 'BS'. I will correct this in the
next revision.

About your confusion about the convergence layer eventually being
located in the ASN-GW: Yes, the WiMAX network specification allows that
all or part (i.e. classification) of the convergence sublayer is located
in the ASN-GW.

I would like to stop here discussions about pros and cons of different
functional decompositions of the WiMAX network architecture. The I-D
should focus on the protocol issues and not on the benefits and
drawbacks of particular implementations.

Bye
Max

-----Original Message-----
From: Erik Colban [mailto:[email-masked]] 
Sent: Tuesday, June 20, 2006 10:08 PM
To: Riegel, Maximilian
Cc: [email-masked]
Subject: RE: [16ng] Submission
ofdraft-riegel-16ng-ip-over-eth-over-80216-00.txt

Hi Max,

I am a little confused about the distribution of the BS into an ASN-GW
and a BS. Just to make it clear, you are not thinking that the
convergence sublayer, which is part of the MAC, could be located at the
ASN-GW, and that one would tunnel the MAC SDUs from the ASN-GW to the
MAC CPS layer at the BS, are you?

Assuming that the MAC CS layer is at the BS and separate from the ASN-GW
and that MS1 and MS2 are both served by the same BS. If an Ethernet
frame were sent from SS1 to SS2(i.e., the Ethernet MAC destination
address is one that belongs to a host at SS2), the Ethernet frame is
sent from SS1 to the BS and is then delivered from the BS CS layer to
the Ethernet layer above at the BS. The BS blindly forwards the Ethernet
frame to the ASN-GW through a tunnel, despite the fact that it would
have had to have learned that the destination MAC address belongs to a
host at SS2. The ASN-GW, which is acting as a bridge, sends the Ethernet
frame back to the BS through a tunnel, and the BS passes the Ethenet
frame down to the MAC CS for delivery to SS2. The IP layer (or any layer
above Ethernet, e.g., PPP, etc.) is transparent between SS1 and SS2. Is
this a correct understanding? If you do bridging at the BS, as you
mention in your email, then the Eth frame would bypass the ASN-GW. Would
the BS filter such frames to prevent this from happening?

Your draft mentions ASN. If it is supposed to be network architecture
agnostic, what are the network architecture assumptions of this draft?
What is ASN? There is no entry for ASN in the terminology section.

Thanks,

Erik

-----Original Message-----
From: [email-masked]
[mailto:[email-masked]] On Behalf Of Riegel,
Maximilian
Sent: Tuesday, June 20, 2006 1:33 AM
To: Syam Madanapalli
Cc: [email-masked]
Subject: RE: [16ng] Submission
ofdraft-riegel-16ng-ip-over-eth-over-80216-00.txt

Syam,

According to the scope and name of the working group (16ng) my intention
was to keep the draft agnostic to a particular access network
architecture and to focus on the generic 802.16 protocol architecture.
If you replace 'BS' in the specification part of the I-D by the WiMAX
term 'ASN', you will get an imagination, how the specification fits into
the WiMAX network architecture. As WiMAX knows about a couple of
different models for the functional split between BS and ASN-GW
(including no split at all) the bridging function may be implemented in
either place depending on the particular ASN profile and the type and
granularity of the GRE tunnels between BS and ASN-GW.

Assuming that the SS is some kind of CPE with an integrated Ethernet
bridge (switch) for connecting hosts behind the SS, the bridge at the BS
side does not get knowledge about a particular MAC address attached to
the bridge in the SS prior to the first packet coming upstream. Only in
the special case of a 'single host' terminal, the bridge can learn the
MAC address out of the establishment of the MAC connection.

Bye
Max

-----Original Message-----
From: Syam Madanapalli [mailto:[email-masked]] 
Sent: Tuesday, June 20, 2006 5:01 AM
To: Riegel, Maximilian
Cc: [email-masked]
Subject: Re: [16ng] Submission of
draft-riegel-16ng-ip-over-eth-over-80216-00.txt

Hello Max,

A couple of questions:

1. It is not clear how this draft fits into the WiMAX Network model.
e.g. In WiMAX all the packets travel to ASN GW before being delivered
to destination i.e. the MAC transport connection is extended all the way
to ASN GW. So I am wondering how this bridging functionality fits into
this kind of architecture.

2. Why cannot the bridge learn the MAC addresses from the establishment
of
802.16 MAC connections?

Thank you,
Syam

On 6/19/06, Riegel, Maximilian <[email-masked]> wrote:
> Dear Editor,
>
> I would like to submit the individual I-D
> draft-riegel-16ng-ip-over-eth-over-80216-00.txt aimed for discussion
in
> the 16ng BOF/WG.
>
>        Transmission of IP Packets over Ethernet over IEEE802.16
>            draft-riegel-16ng-ip-over-eth-over-80216-00.txt
>
> Abstract
>
>   This document describes the special behavior of the Ethernet
>   emulation on top of IEEE802.16 to efficiently support the
>   transmission of IPv4 as well as IPv6 packets over IEEE802.16 radio
>   links.
>   Due to resource constraints of radio transmission systems and the
>   limitations of the IEEE802.16 MAC layer for the emulation of
>   Ethernet, the transmission of IP over an emulated LAN on top of
>   IEEE802.16 may considerably benefit by adding IP specific support
>   functions within the Ethernet emulation on top of IEEE802.16.
>
>
>
> Please fetch the full document by
>
http://www.max.franken.de/ids/draft-riegel-16ng-ip-over-eth-over-80216-0
> 0.txt
>
> Kind regards
> Max
>
>
> _______________________________________________
> 16ng mailing list
> [email-masked]
> http://eeca16.sogang.ac.kr/mailman/listinfo/16ng
>

_______________________________________________
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---

From: "Erik Colban" <[email-masked]>
Date: Tue, 20 Jun 2006 17:40:34 -0700

Max,

I was not trying to compare the pros and cons of different ASN
architectures. My point is to focus on transmission of Ethernet frames
from one SS to another SS attached to the same BS. If the BS acts as a
bridge, then the frames would be delivered from an SS, via the BS to the
other SS. Depending on if and where accounting is done, this could
by-pass accounting. For this reason or other, one may want to filter
such frames, allowing an SS to send frames only toward the
ISP/CSN/BRAS/ASN-GW or what have you, and not to an SS connected to the
same BS. In the Filtering section (4.1.2) you do not mention anything
about filtering packets received from the SS. 

I also wonder why you require support for filtering of
broadcast/multicast messages received on a network side port, but not
for broadcast/multicast  messages that are received from an SS. 

Thanks,

Erik 

-----Original Message-----
From: Riegel, Maximilian [mailto:[email-masked]] 
Sent: Tuesday, June 20, 2006 2:48 PM
To: Erik Colban
Cc: [email-masked]
Subject: RE: [16ng] Submission

Erik,

Bye
Max

-----Original Message-----
From: Erik Colban [mailto:[email-masked]] 
Sent: Tuesday, June 20, 2006 10:08 PM
To: Riegel, Maximilian
Cc: [email-masked]
Subject: RE: [16ng] Submission

Hi Max,

Thanks,

Erik

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

Syam,

Bye
Max

-----Original Message-----
From: Syam Madanapalli [mailto:[email-masked]] 
Sent: Tuesday, June 20, 2006 5:01 AM
To: Riegel, Maximilian
Cc: [email-masked]
Subject: Re: [16ng] Submission of

Hello Max,

A couple of questions:

Thank you,
Syam

in