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paolopoz
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[Solved] OSPFv2 neighbor x.x.x.x: state change from Full to Down

Thu Apr 06, 2017 11:13 am

Hello!
I have 2 routers with OSPF neighboring over a radio link (Ubiquiti). It happens that the link state goes randomly down even if the radio link is always up and running.
Both routers have been upgraded to 6.38.5. One is a CCR1009, other is a RB2011. CPU resources are within good margins. OSPF network type on interface is point-to-point. All other parameters to defaults, so dead timer interval is set to 40s.
We checked the link by putting a static route to the remote router, then enabling a ping every 5s: when OSPF goes down the link stays up.
I also mangled the OSPF packets (by mangling multicast packets) to set DSCP to 46 so that the link gives them priority, with no luck.
Any idea on what else I could check?
Thanks!
Last edited by paolopoz on Tue May 02, 2017 4:12 pm, edited 1 time in total.
 
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shaoranrch
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Re: OSPFv2 neighbor x.x.x.x: state change from Full to Down

Thu Apr 06, 2017 6:20 pm

Hello!
I have 2 routers with OSPF neighboring over a radio link (Ubiquiti). It happens that the link state goes randomly down even if the radio link is always up and running.
Both routers have been upgraded to 6.38.5. One is a CCR1009, other is a RB2011. CPU resources are within good margins. OSPF network type on interface is point-to-point. All other parameters to defaults, so dead timer interval is set to 40s.
We checked the link by putting a static route to the remote router, then enabling a ping every 5s: when OSPF goes down the link stays up.
I also mangled the OSPF packets (by mangling multicast packets) to set DSCP to 46 so that the link gives them priority, with no luck.
Any idea on what else I could check?
Thanks!
The usual problem with radio links like the one you're describing is the lack of proper support for multicast traffic (heavily used by OSPF and most routing protocols except BGP), if the problem is this (and it usually is), should be solved by setting the ospf network type on both routers as NBMA in the interfaces used to connect via the Wireless Link.
/routing ospf interface add=interface_name network-type=nbma
This forces OSPF to use unicast packets instead of multicast packets.

You'll also need to set the nbma-neighbor in:
/routing ospf nbma-neighbor
 
idlemind
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Re: OSPFv2 neighbor x.x.x.x: state change from Full to Down

Tue Apr 11, 2017 6:49 am

Also, confirm your OSFP hello-timer just to triple check it's still at the default of 10s.

An alternative is to use a GRE tunnel which would traverse the radio link without any fear of multicast packet being molested or lost and allow multicast to work properly. Still it may be far simpler to change to NBMA.
 
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paolopoz
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Re: OSPFv2 neighbor x.x.x.x: state change from Full to Down

Tue May 02, 2017 4:12 pm

Thank you all.
By setting the OSPF neighbor to NBMA I fixed the problem!
 
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Re: [Solved] OSPFv2 neighbor x.x.x.x: state change from Full to Down

Tue May 02, 2017 11:31 pm

what is your mtu size ?
 
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paolopoz
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Re: [Solved] OSPFv2 neighbor x.x.x.x: state change from Full to Down

Wed May 03, 2017 5:25 pm

1500
 
mducharme
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Re: [Solved] OSPFv2 neighbor x.x.x.x: state change from Full to Down

Wed May 03, 2017 8:43 pm

Hello!
I have 2 routers with OSPF neighboring over a radio link (Ubiquiti). It happens that the link state goes randomly down even if the radio link is always up and running.
Both routers have been upgraded to 6.38.5. One is a CCR1009, other is a RB2011. CPU resources are within good margins. OSPF network type on interface is point-to-point. All other parameters to defaults, so dead timer interval is set to 40s.
We checked the link by putting a static route to the remote router, then enabling a ping every 5s: when OSPF goes down the link stays up.
I also mangled the OSPF packets (by mangling multicast packets) to set DSCP to 46 so that the link gives them priority, with no luck.
Any idea on what else I could check?
Thanks!
What Ubiquiti radio link is this? AirFiber or AirMax?
 
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paolopoz
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Re: [Solved] OSPFv2 neighbor x.x.x.x: state change from Full to Down

Tue May 09, 2017 10:21 am

PowerBeam M5 on one side and Rocket M5 on the other.
 
tribud
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Re: [Solved] OSPFv2 neighbor x.x.x.x: state change from Full to Down

Tue May 09, 2017 10:33 am

I have ospf running well on Rocket M5 after switch the network type to nbma

Sent from my Redmi 3 using Tapatalk
 
chillisock7
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Re: OSPFv2 neighbor x.x.x.x: state change from Full to Down

Sun Jul 22, 2018 11:44 am

This works like a charm, very interesting.
Hello!
I have 2 routers with OSPF neighboring over a radio link (Ubiquiti). It happens that the link state goes randomly down even if the radio link is always up and running.
Both routers have been upgraded to 6.38.5. One is a CCR1009, other is a RB2011. CPU resources are within good margins. OSPF network type on interface is point-to-point. All other parameters to defaults, so dead timer interval is set to 40s.
We checked the link by putting a static route to the remote router, then enabling a ping every 5s: when OSPF goes down the link stays up.
I also mangled the OSPF packets (by mangling multicast packets) to set DSCP to 46 so that the link gives them priority, with no luck.
Any idea on what else I could check?
Thanks!
The usual problem with radio links like the one you're describing is the lack of proper support for multicast traffic (heavily used by OSPF and most routing protocols except BGP), if the problem is this (and it usually is), should be solved by setting the ospf network type on both routers as NBMA in the interfaces used to connect via the Wireless Link.
/routing ospf interface add=interface_name network-type=nbma
This forces OSPF to use unicast packets instead of multicast packets.

You'll also need to set the nbma-neighbor in:
/routing ospf nbma-neighbor
 
xaviertorres
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Re: [Solved] OSPFv2 neighbor x.x.x.x: state change from Full to Down

Fri Jul 16, 2021 6:29 pm

Thanks by the support, I got the same problem using a RB3011 ( as main) and a RB750GR3 ( as a secondary) in the other side, version of both is 6.48.1 and using antennas POWER BEAM 400-AC-GEN2 and the problem seems to be fixed by putting in both sides the "Network Type: nbma" and declarating NBMA Neighbors the IP of the other side.
 
gabrielpc1190
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Re: [Solved] OSPFv2 neighbor x.x.x.x: state change from Full to Down

Tue Nov 15, 2022 5:05 am

I was suffering the same symtom but over an OpenVPN link between a 7.6 CCR-1016-12G and a 7.6 CCR-2004-16G-2S+.
I have many other tunnels and OSPF works perfect, but this one didn't until I changed the network type to NBMA.

Thank you!

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