Subject: Re: updated draft-petrescu-autoconf-ra-based-routing-05.txt - RAs for routing between moving networks

From: Dan Lüdtke <[email-masked]>
Date: Mon, 4 Aug 2014 15:44:45 +0200

Hi Alexandru,

> Each Mobile Router multicasts special RAs on the egress interface, containing the Mobile Network Prefix that is assigned to its moving network.

Could there be a situation where "normal" and "special" RAs are being
sent by the same router? If so, how will they differ despite the M-Bit
set? Will this lead to routers sending two types of RAs? Is there a
special reason why we do not mark the individual Route Information
Option with a M-Bit but the whole RA?

I tried to do a sketch how to implement this draft into the "ratools"
daemon, at came accross the mentioned questions.

Cheers

Dan

On Tue, Jul 22, 2014 at 12:00 PM, Alexandru Petrescu
<[email-masked]> wrote:
> Hello,
>
> We have updated the draft
> "RAs for routing between moving networks"
> http://tools.ietf.org/html/draft-petrescu-autoconf-ra-based-routing-05
>
> This draft describes an extension to be carried by RAs containing IP
> prefixes to be exchanged between mobile routers ('exchanged' - as opposed to
> 'announcing' prefixes active on links).
>
> The implementation of this extension allows 1-hop neighboring vehicles to
> establish IP paths between any pair of onboard IP-addressable devices; one
> potential application is a live videostream sent by an IP camera in a large
> vehicle to an IP display in the following vehicle, to help during
> view-obstructing situations.
>
> This -05 update is minor - just added a reference to another draft which may
> present similarities.
>
> Alex
>
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-- 
Dan Lüdtke
http://www.danrl.de

---

From: Alexandru Petrescu <[email-masked]>
Date: Wed, 06 Aug 2014 20:44:30 +0200

Le 04/08/2014 15:44, Dan Lüdtke a écrit :
> Hi Alexandru,
>
>> Each Mobile Router multicasts special RAs on the egress interface,
>> containing the Mobile Network Prefix that is assigned to its
>> moving network.
>
> sent by the same router?

Yes, certainly.  For example a MR in a vehicle may send a special RA on
the egress interface (e.g. 802.11p connecting to other vehicles) and a
normal RA on the ingress interface (e.g. 802.11ac inside the vehicle,
towards the passengers' tablets).

> If so, how will they differ despite the M-Bit set? Will this lead to
> routers sending two types of RAs? Is there a special reason why we do
> not mark the individual Route Information Option with a M-Bit but the
> whole RA?

Right, that is a good point.  An encoding where that is performed may be
better than in the whole RA.

Can the RIO contain a new flag (is there some place in it)?  The reason
there is a special bit (M) in the RA header is that it is there that we
found a place to encode a new functionality, at a time when the RA Flag
Expansion bits was beco,ing an RFC.  Maybe it was not the right place.

> daemon, at came accross the mentioned questions.

This is very good to do.  May I ask in which context are you trying to
implement this?  For what kind of applications?

Alex

>> We have updated the draft "RAs for routing between moving networks"
>>
>> prefixes to be exchanged between mobile routers ('exchanged' - as
>> opposed to 'announcing' prefixes active on links).
>>
>> The implementation of this extension allows 1-hop neighboring
>> vehicles to establish IP paths between any pair of onboard
>> IP-addressable devices; one potential application is a live
>> videostream sent by an IP camera in a large vehicle to an IP
>> display in the following vehicle, to help during view-obstructing
>> situations.
>>
>> This -05 update is minor - just added a reference to another draft
>> which may present similarities.
>>
>> Alex
>>
>> [email-masked] Administrative Requests:
>> https://www.ietf.org/mailman/listinfo/ipv6