[riot-devel] RIOT+ULAs: no router entry

Thomas C. Schmidt t.schmidt at haw-hamburg.de
Fri Apr 22 12:41:22 CEST 2016


this may be.

In any case, the erroneous behavior described by smlng should not depend 
on the use of ULAs.

Proposal to smlng: Please use global unicast addresses and confirm the 
misbehavior. Strip off ULA from the discussion thereafter.


On 22.04.2016 12:33, Cenk Gündogan wrote:
> Hey,
> That sounds like the problem described in this issue [1].
> The current master / release candidate version
> should include a "workaround" fix for that.
> Cheers,
> Cenk
> [1] https://github.com/RIOT-OS/RIOT/issues/5122
> On 04/22/2016 12:19 PM, smlng wrote:
>> Hi everyone,
>> I'm testing COAP between RIOT on Phytec pba-d-01-kw2x and Linux on RasPi+Openlabs using ULA IP addresses.
>> On the Pi I run a 'radvd' to advertise a ULA prefix to RIOT, which works:
>>    - RIOT sends RS after boot
>>    - the Pi answers with RA containing ULA prefix
>>    - RIOT configures ULA IP on 6lo iface
>> COAP (or communication in general) via ULA IP works, as long as RIOT has the Pi in its routers cache. However, sometimes RIOT _forgets_ or does not set a routers entry for the Pi at all. In that case communication is not possible via ULAs, using link-local IPs works all the time. The issue seems be with the RS+RA processing. I found that sometimes RIOT does not create a routers entry on reception of a RA - though it does configure the ULA prefix correctly.
>> I just had the case that RIOT configures the ULA _and_ sets a routers entry, hence communication was working. At least for about 15min, but then RIOT send another RS, Pi answers with RA, RIOT still has ULA IP configured -- BUT the routers entry for the Pi is gone and communication fails. Again: using link-local IPs still works.
>> Btw. even when communication via ULAs is working, RIOT never creates a ncache entry for ULA IP of the Pi but it did create an ncache entry for link-local IP of the Pi. I thought the latter is not required/allowed in 6lo but for ULAs it should create an entry?
>> Has somebody else observed this behavior or any hints how to resolve this?
>> Thanks, best
>>     Sebastian
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>> devel at riot-os.org
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Prof. Dr. Thomas C. Schmidt
° Hamburg University of Applied Sciences                   Berliner Tor 7 °
° Dept. Informatik, Internet Technologies Group    20099 Hamburg, Germany °
° http://www.haw-hamburg.de/inet                   Fon: +49-40-42875-8452 °
° http://www.informatik.haw-hamburg.de/~schmidt    Fax: +49-40-42875-8409 °

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