[Server-devel] Network addressing for activation-over-IBSS

Martin Langhoff martin.langhoff at gmail.com
Wed Feb 4 18:17:15 EST 2009

2009/2/5 Daniel Drake <dsd at laptop.org>:
> I have modified the XO activation initramfs to attempt to locate a
> lease server on an XS on each open infrastructure network that can be
> found (early patch attached).

Great -- I am not too conversant on the initrd code, probably makes
sense to repost it to devel@ where cscott and mstone lurk...

> The XS does not bind the server to the IPv6 address correctly (perhaps
> we can work on that)., so it currently runs over IPv4

True - the XS runs an IPv4 infra.

> But assuming we want a working IPv4 implementation... we need to
> figure out a way of getting the XOs to address themselves in a way
> compatible with the school server. The current IPv4 code picks an
> address (randomly) at 172.18.16.xx and this does not work with the XS.
> I also am quite confused by the XS network interface setting.

The XS routing routes 172.18.16.xx the first active antenna (if
present). DHCP never assigns an IP address on that range.

> We need to choose an appropriate address range which the XOs can
> suitably randomly assign themselves in, not covered by DHCP leases,
> and make sure that an appropriate interface is "listening" (at least
> acting as a gateway) on the XS. At the moment I am using 172.18.1.x
> which seems to be free of dhcp assignments.

According to Wad's original schema, where the plan was to scale out
aggressively, the 172.18.1.x range was for the main wired NIC of each
XS. My plan is to scale up before we scale out (farming out highly
integrated services without causing havoc and bottlenecks is
non-trivial), but I am keeping the same routing model as scaling out
is still a valid strategy.

Still, the potential number of XSs in a network is very low.

So a safe thing would be to pick a random IP address in when using a/b/g accesspoints, and 172.18.16.xx when
trying mesh channels.


 martin.langhoff at gmail.com
 martin at laptop.org -- School Server Architect
 - ask interesting questions
 - don't get distracted with shiny stuff  - working code first
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