Re: [v6ops] draft-ietf-v6ops-64share

[Alexandru Petrescu <[e-mail]>]

Le 24/01/2013 13:58, Vízdal Aleš a écrit :
>> -----Original Message----- From: [e-mail]
>> [mailto:[e-mail]] On Behalf Of Alexandru Petrescu
>> Sent: Thursday, January 24, 2013 10:56 AM To: [e-mail]
>> Subject: Re: [v6ops] draft-ietf-v6ops-64share
>
> Alex,
>
>>> To my understanding there is no link-layer addressing at the
>>> 3GPP interface, so it wouldn't be easy to do l2 bridging.
>>
>> Well it depends.
>>
>> In general I think very many cellular interfaces on the UE do not
>> use link-layer addressing.  The devices have 'all-zero' MAC
>> address, use the "NO_ARP" flag and so on.
>
> What are you seeing is not the 3GPP link traffic, but the Ethernet
> emulation done by the modem firmware.

YEs to some extent.

But what that firmware does may be more than simple emulation.

(an emulator would not generate packets at its will but only upon request).

An IP stack is happier to work with an emulator than with a 3GPP link.

> To be able to sniff on the 3GPP interface level you would need a
> tracer to see what's happening there.

Ok, but what is a tracer?  Where can I obtain one?

Do you mean wireshark?

Alex

>
>> However, more recent devices (e.g. USB keys for LTE: bandrich
>> C502, huawei e392, more) using qualcomm chipsets in some instances,
>> using 'qmi' interfaces and drivers, exhibit a form of link-layer
>> addressing.
>>
>> First, these devices use centrally-allocated IEEE identifiers for
>> Company_ID.  Suprisingly to some, the well known file oui.txt
>> exhibits such id's for manufacturers of 3GPP-compatible equipment
>> (traditionally it mentions only manufacturers of IEEE-compatible
>> equipment).
>>
>> Second, some kernel modules, for instance in the 'qmi' family, form
>> the last 3 bytes of a 48bit address.
>>
>> Finally, wireshark dumps of packets emitted by these cellular
>> interfaces show Ethernet headers with MAC src and dst addresses,
>> and interprets them according to oui.txt (wireshark interpretation
>> is a good indicator about the width of the spread of some
>> protocol).
>>
>> These three aspects make me think that maybe the new and future
>> cellular interfaces may be more and more link-layer addressable.
>>
>> One consequence is the arrival of the use of classical ND on these
>> links, and, why not, the bridging forms which are customary on
>> Ethernet links.
>>
>> (caveat emptor: yes much intelligence exists in the small computer
>> in a USB key that may make some things appear what they are not -
>> proxying, on behalf of, etc. - yet they don't run the IP stack,
>> it's the USB Host computer which runs the stack).
>>
>> Alex
>
> Ales
>
>