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

smlng s at mlng.net
Fri Apr 22 13:19:37 CEST 2016


Hi Cenk, and all,

I'm running my tests with latest master and 2016.04-branch, same behavior. Minus the fact, that the router entry in RIOT is created or missing in a somewhat 'non-deterministic' fashion.

Best,
  Sebastian

> Am 22.04.2016 um 12:33 schrieb Cenk G√ľndogan <cenk.guendogan at fu-berlin.de>:
> 
> 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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> 
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