#4069 NORM First D: Connecting to school server network should happen automatically if XO comes into its range

[Zarro Boogs per Child]

#4069: Connecting to school server network should happen automatically if XO comes
into its range
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  Reporter:  arjs             |       Owner:  dcbw                                
      Type:  defect           |      Status:  new                                 
  Priority:  normal           |   Milestone:  First Deployment, V1.0              
 Component:  network manager  |     Version:                                      
Resolution:                   |    Keywords:  wireless, range, ip, address, assign
  Verified:  0                |  
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Comment(by dcbw):

 What the network bits don't do right now is periodically try to get an
 address from the school server.  There's no way to tell if a school server
 is "in range" except by trying to acquire an address from it and getting a
 reply from something.  This is probably a good thing to do (or, at least,
 notify the user that a new school server has been found on channel X via a
 bubble and let them _explicitly_ jump to the server).  The network stuff
 also doesn't yet keep pinging the server while it _is_ connected and
 switch back to link-local if the server can't be reached after a while
 (ie, you walked home from school and can no longer reach the server).

 The  problem here is that jumping to the school server would interrupt any
 active connections you may have, and your activities would be interrupted
 as well.  So we have to weigh the cost of potentially interrupting and
 link-local shared activities the user may have been participating in [1]
 versus the benefit of the connectivity the server provides.

 Some of this could be alleviated later if things were modified to keep the
 link-local IP address _always_ (but this has other problems [2]) and
 opportunistically acquire a second address when possible.  That way
 connections don't get broken until the connectivity is /actually/ gone.

 [1] if not in range of a server but still with other kids, I sure hope
 people are still playing games and sharing activities but the no-
 connectivity link-local case may well be less important than server-
 assisted connectivity

 [2] if the XO has an IPv4 LL address and walks into a room with another XO
 that has the same IPv4 LL address (since there is potential overlap with
 only about 64,000 addresses available in the IPv4 LL address space), bad
 things happen.  I believe that IPv4 LL addressing only accounts for
 initial address acquisition, not necessarily on-the-fly with highly mobile
 users where overlap is much more likely

-- 
Ticket URL: <https://dev.laptop.org/ticket/4069#comment:2>
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