Issue with L2PTP Tunnels

[Fatih Berkay Sarpkaya]

Dear FABRIC team,

I hope you are doing well. In my experiment, I am using eight separate 20 Gbps tunnels implemented with subinterfaces. Two of these tunnels (the ones using VLAN tags 300 and 600)  have suddenly stopped working. The remaining tunnels function normally.

These two tunnels previously worked without issues. I have tried reconfiguring the interfaces and rebooting the endpoints, but the problem persists. I am not sure whether the issue is due to a configuration mistake on my side or a problem within the slice network.

Would it be possible for you to check whether there is an issue with these two tunnels, or let me know if there is something I may have overlooked?

My slice ID is: fdf2fd5b-b1b0-46ef-b51a-4d55e0fd5c47

Thank you very much for your help.

Best regards,

Fatih Berkay Sarpkaya

[Komal Thareja]

Hi Fatih,

Thanks for reaching out.

I looked into your slice, and it appears that the two network services associated with VLAN 300 and VLAN 600 are currently in a Closed state. Both reservations show the same ticket update:

“Insufficient resources: No path available with the requested QoS.”

Here are the details:

Reservation ID: 8a83db0f-03f1-44b0-843f-c6e0c2664cfe
Slice ID: fdf2fd5b-b1b0-46ef-b51a-4d55e0fd5c47
Resource Type: L2PTP
State: Closed
Reason: No path available with requested QoS

Reservation ID: 257fae2a-28ca-4430-bb85-77864b3d5c25
Slice ID: fdf2fd5b-b1b0-46ef-b51a-4d55e0fd5c47
Resource Type: L2PTP
State: Closed
Reason: No path available with requested QoS

This indicates that the system was unable to allocate a viable path for these two tunnels during your most recent renewal window, which is why they are not active now.

If you would like, you can try the following:

• Re-declare or re-submit these two network services in your slice.
• Lower the QoS requirement temporarily to see if a path becomes available.

Please feel free to reach out if you need help updating the slice or if you would like us to investigate further.

Best regards,
Komal

[Fatih Berkay Sarpkaya]

Hi Komal,

Thank you for your response. I created a new slice a few days ago and extended its expiration date to December 5 right away. The tunnels were working correctly for the last 2–3 days. However, when I tested again today, I no longer have connectivity over the tunnels with VLAN tags 100, 600, and 800.

Could you please check my slice again and confirm whether these tunnels have entered the Closed state? If so, could you help me understand the exact reason? My understanding was that once the slice is reserved until a certain date, the associated tunnels should remain reserved as well.

Additionally, could you please provide guidance on how to properly “re-declare” or “re-submit” these network services within the slice, if that is the correct approach?

slice id= 698e8e21-3926-451f-ad94-24ea5db4a822

Thank you very much for your help.

Best regards,

Fatih Berkay Sarpkaya

[Komal Thareja]

Hi Fatih,

I see that the following three slivers are currently in a Closed state. Please note that a renew is not a single-shot operation.

When you renew a slice, it transitions into the Configuring state and reports which individual slivers were successfully extended and which were not. You can verify this in the Portal by viewing the slice topology, or—if you are renewing from JupyterHub—fablib will explicitly report which slivers failed to renew.

You can also check this programmatically:

slice = fablib.get_slice(slice_name)
slice.list_slivers()

Here are the affected reservations:

• Reservation ID: 990127bd-aa06-4992-8847-c76654faf0e8
  State: Closed
  Reason: Insufficient resources — No path available with the requested QoS
• Reservation ID: 30dd426f-9ddc-424b-bec7-ca8631540ea4
  State: Closed
  Reason: Insufficient resources — No path available with the requested QoS
• Reservation ID: cb4372e4-fb05-454e-8662-f53e297689f8
  State: Closed
  Reason: Insufficient resources — No path available with the requested QoS

These slivers were not able to secure a viable path during renewal, which is why they are now in a closed state.

To re-add these network services, you can modify the slice as follows:

1. Fetch the current slice topology, remove the closed network services, and submit the slice.
2. Fetch the updated topology, add the required network services again, and submit once more.
3. You can refer to this example for guidance on modifying an existing slice (adding/removing resources):
   fabric_examples/fablib_api/modify_slice/modify-add-node-network.ipynb

Please let me know if you’d like help with the modify workflow or with re-submitting the network services.

Best,
Komal

[Fatih Berkay Sarpkaya]

Hi Komal,

Thank you for the detailed explanation. Last time, I followed your suggestion and re-reserved the affected tunnels, which extended them until December 5. Today, I renewed the slice to December 16, but three tunnels showed errors and I believe they will still expire on December 5.

Given my ongoing work, I need these tunnels to remain available throughout this month. What would you recommend as the best approach to keep them active as long as possible? Also, I don’t think fablib.list_links() exposes the reservation start/end times, so I am not able to check the future reservation durations of my existing tunnels.

If there is a way for me to view the currently reserved time windows of my L2PTP links, I could try reserving them for a longer period in advance (although I’m not sure if that is appropriate for an already existing slice.)

Any guidance on how to manage these renewals effectively would be very helpful.

Thank you,

Fatih Berkay Sarpkaya

[Komal Thareja]

Hi Fatih,

Apologies for the delayed response, but most likely the links you are requesting have been reserved in advance causing your renew to fail. I will look at other reservations today and work with the other users to see if we can get your slice stay up for longer duration. I will keep you posted!

Best,

Komal

[Fatih Berkay Sarpkaya]

Hi Komal,

Thank you so much for your help. Currently, I am using eight tunnels, each at 20 Gbps. Since we observed some issues at that capacity, we decided to reduce them to 10 Gbps (eight tunnels at 10 Gbps). I believe the correct way to update my slice is to remove the existing tunnels and then add new ones with the lower bandwidth. I will work on making that change today, and I hope I can reserve them for a longer duration.

Thank you.

Best regards,

Fatih Berkay Sarpkaya

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