OSPFv3 via Vman hangs at EX_START

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  • Updated 5 years ago
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Hi folks
We had two X450a with core licence connected directly with a cable that was user for OSPFv3 peering. that worked perfectly.
Now we had to put some other extreme switches in the middle that transport this via a VMAN. since then OSPFv3 state is EX_START which is not good.
The two X450a can ping themself using IPv4 and V6 so L2 seems good.
OSPF (for IPv4) works.
Link is in broadcast mode and i tried several MTU settings.
I have XOS 12.3.

Is it a software issue that would be fixed with 15.* or is there something else you can see ?
Any idea will be welcomed. But I don't want to update XOS just to give it a try, these devices are sensitive.

Regards
Alex
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Alex

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Posted 5 years ago

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LeVar Pulliam, Extreme Alumnus

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Alex,

regarding the OSPF configuration, have you tried changing the link-type to "Point-Point"?
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Daniel Flouret, Employee

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Maybe a problem with frame size? Are Jumbo Frames enabled in the vMAN ports?

Remember that vMAN adds 4 bytes to the packet...
(Edited)
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Paul Russo, Alum

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Hey Alex I would be curious on if the two suggestions above have helped.  VMANs are just a L2 tunnel and I have never seen them deny OSPF for end customer networks.

If the two suggestions above do not work, especially Daniel's, then please open a case as this should be working.

Please provide an update if you can.
P
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Alex

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Thanks all for you feedback

Link type cannot be configured. it says :
Warning! Link type configuration is not supported
Link type will always be broadcast
We have Jumbo  enabled all the way between these devices.
I changed MTU size on both OSPFv3 devices by typing :
configure vlan ospfv3_peer router-discovery ipv6 link-mtu 1200
is that the right command to change the frame size ?
If yes, that's what I tried earlier and i think 1200 should be small enough.
PS : I was able to ping with unfragmented packets up to 9100 from one device to the other.

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Alex

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Anyone with an idea where the problem could be ?

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Alex

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Could it be because OSPFv3 uses the link local ip (that are not adjacent) to peer ?
If yes, how tell OSPFv3 to use the regular IPv6 ?
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Paul Russo, Alum

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Hey Alex

Is there a way for you to open a case?  I think having TAC look at the config and run through testing would help a lot to get this worked out.

P
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Alex

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Hi

Problem solved. Extreme says :

PD number

PD4-861837558

Severity

3-Wrong Behavior

Status/SubStatus

Closed / Verified

Platform/Area/Sub Area/Feature

IP:OSPFv3 / App:Common / Existing Feature

Description

In a jumbo frame environment, an OSPFv3 neighbor gets stuck at EX_START.

Workaround

Configure ip-mtu size BEFORE configuring the first IPv6 address for the vlan. (In order to do this, IPv4 address must be configured for the vlan before configuring ip-mtu size even if you intend to use the switch for IPv6 only environment.)

Reproducible

Always

 

Found In

EXOS-12.4.1

Original Product

EXOS 12.3.1

Fixed Build

12.4.0.7

The workaround is realy ugly for us because we need jumbo an as this is solved in build after 12.4.0.7, I decided to update to XOS 15.x.x.x.

I wish the PDs would be easier to find...

Thanks All
Alex