Subject: [16NG] Implementation of IPv6 over IPv6 CS

From: Alexandru Petrescu <[email-masked]>
Date: Thu, 14 Dec 2006 18:45:33 +0100

Let me try to separate the implementation discussion.

Is there any prototype implementation, or almost prototype, of IPv6 over
IPv6 CS.

Does the SS's IPv6 stack add any link-layer header to the IPv6 packet
before delivering  it to the IPv6 CS software?  With ppp it doesn't.

Does the IPv6 stack send an MLD JOIN before receiving an RA from the AR?
  With ppp it doesn't.

How does the IPv6 stack learn the link-local address of the AR?  How
does the IPv6 stack on AR learn the link-local address of MS?

On some existing point-to-point links (non IPv6 CS) this is achieved by
means of an intermediate "link-and-network" layer LCP implementation (or
earlier IPCP), which negotiates such parameters as IP addresses.  Some
times ROHC is used too for PPP.  ROHC does what the "classification" in
CS do: identify headers, suppress, reconstruct at other end.  ROHC is
not the only way to achieve header compression, there are other
compression schemes: IP HEader Compression over PPP, BSD compression
protocol, PPP compression protocol CCP, etc.

I understand there's statement saying PPP is not used, and that 802.16
protocol is used for setting up the point-to-point link.  So is there an
implementation of that 802.16 protocol?  Or plan, or almost prototype.

Alex

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From: Basavaraj Patil <[email-masked]>
Date: Thu, 14 Dec 2006 13:43:05 -0600

Alex,

I guess you are confused by the concept of the PtP link.
Well to understand this you have to understand the 802.16 MAC to a certain
extent. 
The 802.16 MAC is connection oriented (quoted from the .16 spec). So a
transport connection over the air interface which is used to send/receive IP
packets (in the context of this discussion) is a PtP connection that exists
between the MS and BS. Now this PtP connection can be extended to the AR by
an L2 tunnel. The combination of the Transport connection over the
air-interface and the L2 tunnel between the BS and AR (in case the AR is not
a function in the BS itself) forms a PtP link over which IPv6 runs.
I think a lot of your questions are answered if you were to read the .16
spec. Other responses inline:

> Is there any prototype implementation, or almost prototype, of IPv6 over

Yes.

> before delivering  it to the IPv6 CS software?

No.

> Does the IPv6 stack send an MLD JOIN before receiving an RA from the AR?

It can. But need not. The trigger in the RA is essentially a link-up
associated with an MS (which the AR receives via the virtual link that is
created when the MS has completed network entry procedures).

>   With ppp it doesn't.
> 
> How does the IPv6 stack learn the link-local address of the AR?

Via the RA.

> How

Why does the RA care?

> implementation of that 802.16 protocol?  Or plan, or almost prototype.

Yes. And there is no PPP involved.

-Raj

---

From: Alexandru Petrescu <[email-masked]>
Date: Thu, 14 Dec 2006 21:01:49 +0100

Basavaraj Patil wrote:
> Alex,
> 
> I guess you are confused by the concept of the PtP link. Well to
> understand this you have to understand the 802.16 MAC to a certain 
> extent. The 802.16 MAC is connection oriented (quoted from the .16
> spec). So a transport connection over the air interface which is used
> to send/receive IP packets (in the context of this discussion) is a
> PtP connection that exists between the MS and BS. Now this PtP
> connection can be extended to the AR by an L2 tunnel.

This L2 tunnel again: l2-in-l2?  l3-in-l2?  Or simply naturally an l3
packet in a l2 envelope.  Why calling it a tunnel?

> The combination of the Transport connection over the air-interface
> and the L2 tunnel between the BS and AR (in case the AR is not a
> function in the BS itself) forms a PtP link over which IPv6 runs. I
> think a lot of your questions are answered if you were to read the
> .16 spec.

I think I've read a lot of linklayer specs prior to posting here, and
even ported IPv6 over some.

>> Is there any prototype implementation, or almost prototype, of IPv6
>> over IPv6 CS.
> 
> Yes.

Ok, that should be mentioned.

>> Does the SS's IPv6 stack add any link-layer header to the IPv6
>> packet before delivering  it to the IPv6 CS software?
> 
> No.

Ok.

> associated with an MS (which the AR receives via the virtual link
> that is created when the MS has completed network entry procedures).

So does that trigger tell AR what's the link-local address of SS?  The
AR needs to know the link-local address of SS to send it an RA.

>> How does the IPv6 stack learn the link-local address of the AR?

How does the AR know the link-local address of SS?

>> How does the IPv6 stack on AR learn the link-local address of MS?
> 
> Why does the AR care?

So it knows where to send the RA.

>> On some existing point-to-point links (non IPv6 CS) this is
>> achieved by means of an intermediate "link-and-network" layer LCP
>> implementation (or earlier IPCP), which negotiates such parameters
>> as IP addresses.  Some times ROHC is used too for PPP.  ROHC does
>> what the "classification" in CS do: identify headers, suppress,
>> reconstruct at other end.  ROHC is not the only way to achieve
>> header compression, there are other compression schemes: IP HEader
>> Compression over PPP, BSD compression protocol, PPP compression
>> protocol CCP, etc.
>> 
>> I understand there's statement saying PPP is not used, and that
>> 802.16 protocol is used for setting up the point-to-point link.  So
>> is there an implementation of that 802.16 protocol?  Or plan, or
>> almost prototype.
> 

Ok, so by consequence I believe no LCP, nor IPCP, no BSDComp are used, 
right?

Alex