Network association algorithm

[Javier Cardona]

John, Dan,

Attached you'll find a flowchart that illustrates better the changes
that I'm proposing.

Cheers,

Javier

PS.  The diagram is available online at gliffy.com.  If anyone wants
to add changes let me know and I'll add you to the list of
collaborators.


On 5/4/07, Javier Cardona <javier at cozybit.com> wrote:
> Hi John, Dan,
>
>
> After chatting with Dan I finally understood your flowchart (pardon my
> thickness,  I was having some nomenclature problems..).  I learned yesterday
> that:
>
>  1) "established MPPs" are MPPs with multiple mesh interfaces, at most one on
>  each channel 1,6 and 11.  They are also called "school servers" and will not
>  be moving around.
>
>  2) "ad-hoc MPPs" are xo's that act as MPPs, as portals they were
> originally conceived.
>
>  3) Addresses are assigned by DHCP because link local addresses cannot be
>  routed.  L3 routing is done by MPPs across mesh segments at different
>  channels.
>
> Based on this understanding, I would like to suggest a change in the way DHCP
> is used in your proposal.  The current flow is:
>
>        +           +
>       / \         / \
>      /   \ y     /   \ y
> ----+DHCP?+-----+ MPP?+----
>      \   /       \   /
>       \ /         \ /
>        + n         + n
>        |           |
>        +-----------+
>        |
>
> This approach separates IP address assignment (DHCP) and MPP detection and path
> selection.  I believe these two functions which can be combined in one:
>
> 1. xo sends a DCHP request to L2 address ANY_MPP.  This is a standard
> DHCPREQUEST sent to a unicast address.  The only thing "non-standard" would be
> done at the dhcp client:  this DHCPREQUEST would have the L2 anycast
> address, the L3 broadcast address and would be injected at L2 using
> the linux packet interface.
>
> 2. MPP assigns an IP address and sends a DHCPACK to the L2 address that was in
> the DHCPREQUEST.  That's vanilla DHCP server.
>
> 3. The xo knows the DHCPACK comes from an MPP because it's a response from a
> request sent to the ANY_MPP address.
>
> Advantages:
>
> 1. Faster configuration.
> 2. No broadcast+anycast traffic, only anycast.
> 3. Replaces non-standard MPPREQs with standard DHCP
>
> This model can also be used for ad-hoc MPPs.  In that case ad-hoc MPPs would
> return gateway and DNS information but would not assign an IP address.
>
> What do you think?
>
> Javier
>


-- 
Javier Cardona
cozybit Inc.
p 415 974 6770
f 415 974 6771
c 415 630 0627
e javier at cozybit.com
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Network_Association_Algorithm.jpg
Type: image/jpeg
Size: 154273 bytes
Desc: not available
URL: <http://lists.laptop.org/pipermail/devel/attachments/20070504/02181a61/attachment.jpg>