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FIPTech
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/31 point to point Ethernet links not working

Sun Jul 01, 2012 5:39 pm

I was not able to get /31 point to point Ethernet links working (ROS 5.18).

It seems that ROS is not able to use a /31 even address (the network one) as a local address.

Inside a /31, there is no more directed broadcast address, and the network address (the even one) become the remote or the local address according to wich side of the link we are.


Did anyone got it working ?


On a similar subject, subnet directed broadcast does not work between different subnets. The subnet broadcast is not delivered localy when it is sent from another subnet. This is a problem for Wake on Lan for example. It is possible to use some tricks to avoid using it, but it would be simpler if we could activate directed broadcast on Ethernet interfaces.
 
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mrz
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Re: /31 point to point Ethernet links not working

Mon Jul 02, 2012 10:38 am

RouterOS does not support /31 instead you should use /32
 
oreggin
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Re: /31 point to point Ethernet links not working

Mon Jul 02, 2012 10:42 am

This is a duplicated topic:
http://forum.mikrotik.com/viewtopic.php?f=2&t=63255

@mrz: do you have any information when will be supported RFC3021 in Linux/RoS on ethernet?
 
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Re: /31 point to point Ethernet links not working

Mon Jul 02, 2012 11:22 am

as far as I know not in the near future.
 
FIPTech
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Re: /31 point to point Ethernet links not working

Mon Jul 02, 2012 11:36 am

ok. /32 is working for Ethernet links, even using OSPF (as soon as the point to point ethernet link is declared as a point to point ospf interface on each side).


Perhaps that if we enter a /31 address in winbox or CLI it could be converted to a /32 instead of accepting it and give a not working link ?


Why /31 do not work ? Is it a linux kernel limitation ?

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