Express route circuit down

JoelP 241

Hi,

Our express route went down last week, and all I can see is this when I troubleshoot it. It is saying that the Host OS and Guest OS had maintenance, but not sure why our BGP peering session went down for like 6 hrs.

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KapilAnanth-MSFT 39,461 Reputation points Microsoft Employee

2023-09-26T04:15:28.26+00:00
@JoelP

Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.

I understand that you would like to troubleshoot your ExpressRoute downtime.

May I ask if the issue still persists?

You can use the AzureDiagnostics logs to understand what caused the BGP issue.

Sample Kusto Queries : https://video2.skills-academy.com/en-us/azure/expressroute/monitor-expressroute#sample-kusto-queries

Cheers,

Kapil
JoelP 241 Reputation points

2023-09-26T05:00:45.9666667+00:00

Is there a way to check which BGP peering was down? Can't seem to find that information from anywhere from the virtual network gateway or the circuit.
KapilAnanth-MSFT 39,461 Reputation points Microsoft Employee

2023-09-26T05:31:57.17+00:00
@JoelP

You can use this metric : BGP Availability - Split by Peer

Can you please confirm how you are saying BGP session was down?

Did users experience connectivity loss for 6 hours?

Or was it from the screenshot you shared?

Because,

During maintenance between the Microsoft edge and core network, BGP availability will appear down even if the BGP session between the customer edge and Microsoft edge remains up.

So, if the users have not experienced any connectivity loss, I would say this should be an expected behavior.

You can check the past maintenance activities here : https://video2.skills-academy.com/en-us/azure/expressroute/maintenance-alerts#view-past-maintenance

Cheers,

Kapil
JoelP 241 Reputation points

2023-09-26T05:43:05.1233333+00:00

thank you for sharing the metric split by peer.. this will definitely assist.
KapilAnanth-MSFT 39,461 Reputation points Microsoft Employee

2023-09-26T06:07:11.9066667+00:00

@JoelP

You are welcome.

Can you please confirm if the users actually experienced connectivity loss for 6 hours or not?

As stated above, the metrics may show down during maintenance events.

Cheers,

Kapil
JoelP 241 Reputation points

2023-09-26T06:11:29.7033333+00:00

Hi,

Yes we did lose 6 hour but might be related to a change that was done on our DC but we were struggling to find out what BGP peering session was down, so your metrics should be a good tool to check next time.
KapilAnanth-MSFT 39,461 Reputation points Microsoft Employee

2023-09-26T15:21:58.84+00:00

@JoelP

Sure.

Meanwhile, I shall summarize our discussion and post it as an answer.

Kindly Accept the answer, as this can be beneficial to other community members and close this thread.

And, should there be any follow-up questions or concerns, please let us know and we shall try to address them.

Cheers,

Kapil
KapilAnanth-MSFT 39,461 Reputation points Microsoft Employee

2023-09-28T13:08:16.5933333+00:00

@JoelP

Reaching out to check if there are any questions on this.

Please let us know if we can be of any further assistance here.

Thanks,

Kapil

Please Accept an answer if correct.

Original posters help the community find answers faster by identifying the correct answer.

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KapilAnanth-MSFT 39,461 Reputation points Microsoft Employee

2023-09-26T15:24:33.4266667+00:00
@JoelP

Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.

I understand that you would like to troubleshoot your ExpressRoute downtime.

You can use the AzureDiagnostics logs to understand what caused the BGP issue.

Sample Kusto Queries : https://video2.skills-academy.com/en-us/azure/expressroute/monitor-expressroute#sample-kusto-queries

You informed that the users experienced connectivity loss for almost 6 hours during this maintenance activity.

I suggested you can use the BGP Availability - Split by Peer metric to check if a BGP session was down or not.

However,

During maintenance between the Microsoft edge and core network, BGP availability will appear down even if the BGP session between the customer edge and Microsoft edge remains up.

So, if the users have not experienced any connectivity loss, I would say this should be an expected behavior.

Furthermore, you can check the past maintenance activities here : https://video2.skills-academy.com/en-us/azure/expressroute/maintenance-alerts#view-past-maintenance

Thanks,

Kapil

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Original posters help the community find answers faster by identifying the correct answer.
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