Debugging MS Teams Traffic: Difference between revisions

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This page describes how Skype traffic can be analyzed with the '''Allegro Network Multimeter'''.
This page describes how Microsoft Teams traffic can be analyzed with the '''Allegro Network Multimeter'''.


== Skype client protocols ==
== Microsoft Teams client protocols ==


The Skype client relies on SSL for all control based traffic and RTP for all audio/video based traffic.
The Microsoft Teams clients rely on SSL for all control based traffic and RTP for all audio/video based traffic.


The '''Allegro Network Multimeter''' allows you to search for traffic to the Microsoft cloud, helps to analyze the response time of the SSL encrypted control traffic and analyzes the RTP traffic for quality parameters like packet loss, jitter, etc.
The '''Allegro Network Multimeter''' allows you to search for traffic to the Microsoft cloud, helps to analyze the response time of the SSL encrypted control traffic and analyzes the RTP traffic for quality parameters like packet loss, jitter, etc.


== Skype control traffic ==
== Microsoft Teams control traffic ==


The Skype control traffic is SSL encrypted. This does not allow to decode and analyse the content of the control connection. As SSL uses the TCP as layer 4 protocol, all quality statistics of the TCP connection can be used for debugging. Additionally, the response time for the SSL handshake and the first encrypted SSL data response time is available too.
Microsoft Teams traffic is SSL encrypted. This does not allow for decoding and analysis of the control connection content. Since SSL uses TCP as the Layer 4 protocol, all of the TCP connection quality statistics can be used for debugging. Additionally, the response time for the SSL handshake and the first encrypted SSL data response time is available.


The most important quality parameters are:
The most important quality parameters are:
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* TCP handshake response time
* TCP handshake response time
* TCP retransmission rates
* TCP retransmission rates
* TCP Zero window times
* TCP Zero Window times
* SSL hello handshake respone time
* SSL hello handshake response time
* SSL first data response time
* SSL first data response time


Please read the [[TCP module]] and [[SSL module]] for more information about these and more counters.
Please read the [[TCP module]] and [[SSL module]] for more information on these and more counters.


A simple way to get an overview of the response time for Skype servers is the '''IP statistics''' table. You can use the free text search for "skype" and select the the graph dialog: "TCP response time". This will present you the top IP addresses with a correlated name to '''skype''' and their TCP response time. You can also enable the '''Timing''' columns to view and sort for response times.
A simple way to see an overview of the response time for Microsoft Teams servers is the '''IP statistics''' table. You can use the free text search for "teams" and select the graph dialogue: "TCP response time". This will present you the top IP addresses with a correlated name to '''teams''' and their TCP response times. You can also enable the '''Timing''' columns to view and sort for response times.


[[File:Skype response time.png|600px]]
[[File:Debug_ms_teams_ip_statistics.png|1200px]]


This graph shows you the delay of the TCP stack to confirm the reception for data. Please note that many TCP stacks wait a few milliseconds if there is no data to respond (see [[https://en.wikipedia.org/wiki/TCP_delayed_acknowledgment Wikipedia TCP delayed acknowledgment]]). Any additional delay on top of this time (usually 40 ms) shows a significant delay in the roundtrip time. If you have installed the Allegro close to the Skype client, it will be the roundtrip time of the TCP packets from your network to the Skype cloud.


The used DNS names and IP address ranges can differ for Skype as the control server are made available in the Microsoft cloud with load balancing leading to different servers. A current description for Skype for Business can be found here: [https://techcommunity.microsoft.com/t5/skype-for-business-blog/simplified-port-requirements-for-skype-for-business-online/ba-p/77094]
This graph shows you the TCP stack delay to confirm data reception. Note that many TCP stacks wait a few milliseconds if there is no data to respond to(see [[https://en.wikipedia.org/wiki/TCP_delayed_acknowledgment Wikipedia TCP delayed acknowledgment]]). Any additional delay on top of this time (usually 40 ms) indicates a significant roundtrip time delay. If you have installed the Allegro Network Multimeter close to the Microsoft Teams client, it will be the roundtrip time of the TCP packets from your network to the Teams cloud.


The analysis can also be done for TCP retransmissions and TCP zero window statistics. If you have installed the Allegro close to the Skype client, this will indicate if the data sent to the Skype server required a retransmission on the WAN link or if the receiver buffer is full showing receiver overload.
DNS names and IP address ranges for Microsoft Teams are subject to change regularly, since the control servers in the Microsoft cloud use load balancing, which can point data to different servers.


== Skype audio/video traffic ==
The analysis can also be done for TCP retransmissions and TCP Zero Window statistics. If you have installed the Allegro Netwok Multimeter close to the Microsoft Teams client, this will indicate if the data sent to the Teams server required a retransmission on the WAN link or if the receiver buffer is full, indicating receiver overload.


The Skype audio/video traffic is sent by encrypted RTP frames. As RTP encryption is applied only on the content and not on the RTP header, you can still debug the RTP traffic with the RTP decoder output of the Allegro Network Multimeter.
== Microsoft Teams audio/video traffic ==


To get an overview of which IPs have used RTP, you can use the '''Applications''' → '''RTP statistics''' page and search for skype.
The Microsoft Teams audio/video traffic is sent by encrypted RTP frames. As RTP encryption is applied only on the content and not on the RTP header, you can still debug the RTP traffic with the RTP decoder output of the Allegro Network Multimeter.
 
To get an overview of which IPs have used RTP, you can use the '''Applications''' → '''RTP statistics''' page and search for Teams.


[[File:Skype rtp statistics overview.png|1000px]]
[[File:Skype rtp statistics overview.png|1000px]]


This allows you to see which IP address have used the protocol RTP. It shows an overview of the RTP packet loss and jitter based on RTP sequence numbers. To get detailed information about individual connections, click on the IP address. This will show RTP packet loss and jitter for each connection.
 
This allows you to see which IP address have used the protocol RTP. It shows an overview of the RTP packet loss and jitter based on RTP sequence numbers. To obtain detailed information about individual connections, click on the IP address. This will show RTP packet loss and jitter for each connection.


[[File:Skype rtp statistics ip detailed.png|1000px]]
[[File:Skype rtp statistics ip detailed.png|1000px]]

Latest revision as of 06:41, 21 May 2025

This page describes how Microsoft Teams traffic can be analyzed with the Allegro Network Multimeter.

Microsoft Teams client protocols

The Microsoft Teams clients rely on SSL for all control based traffic and RTP for all audio/video based traffic.

The Allegro Network Multimeter allows you to search for traffic to the Microsoft cloud, helps to analyze the response time of the SSL encrypted control traffic and analyzes the RTP traffic for quality parameters like packet loss, jitter, etc.

Microsoft Teams control traffic

Microsoft Teams traffic is SSL encrypted. This does not allow for decoding and analysis of the control connection content. Since SSL uses TCP as the Layer 4 protocol, all of the TCP connection quality statistics can be used for debugging. Additionally, the response time for the SSL handshake and the first encrypted SSL data response time is available.

The most important quality parameters are:

  • TCP handshake response time
  • TCP retransmission rates
  • TCP Zero Window times
  • SSL hello handshake response time
  • SSL first data response time

Please read the TCP module and SSL module for more information on these and more counters.

A simple way to see an overview of the response time for Microsoft Teams servers is the IP statistics table. You can use the free text search for "teams" and select the graph dialogue: "TCP response time". This will present you the top IP addresses with a correlated name to teams and their TCP response times. You can also enable the Timing columns to view and sort for response times.

Debug ms teams ip statistics.png


This graph shows you the TCP stack delay to confirm data reception. Note that many TCP stacks wait a few milliseconds if there is no data to respond to(see [Wikipedia TCP delayed acknowledgment]). Any additional delay on top of this time (usually 40 ms) indicates a significant roundtrip time delay. If you have installed the Allegro Network Multimeter close to the Microsoft Teams client, it will be the roundtrip time of the TCP packets from your network to the Teams cloud.

DNS names and IP address ranges for Microsoft Teams are subject to change regularly, since the control servers in the Microsoft cloud use load balancing, which can point data to different servers.

The analysis can also be done for TCP retransmissions and TCP Zero Window statistics. If you have installed the Allegro Netwok Multimeter close to the Microsoft Teams client, this will indicate if the data sent to the Teams server required a retransmission on the WAN link or if the receiver buffer is full, indicating receiver overload.

Microsoft Teams audio/video traffic

The Microsoft Teams audio/video traffic is sent by encrypted RTP frames. As RTP encryption is applied only on the content and not on the RTP header, you can still debug the RTP traffic with the RTP decoder output of the Allegro Network Multimeter.

To get an overview of which IPs have used RTP, you can use the ApplicationsRTP statistics page and search for Teams.

Skype rtp statistics overview.png


This allows you to see which IP address have used the protocol RTP. It shows an overview of the RTP packet loss and jitter based on RTP sequence numbers. To obtain detailed information about individual connections, click on the IP address. This will show RTP packet loss and jitter for each connection.

Skype rtp statistics ip detailed.png