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SG350 / 2 Trunks / "Main" + "Alternate" / Dropouts

mtzstr
Level 1
Level 1

Dear community, 
we have a Problem with our Cisco SG350 in our configuration. Google research completed -> no identical problem found...

 

Our setup:

2x SG350 / identical setup / 2 VLAN (1: 1-3 / 2: 4 - 8) / RTSP-Trunks on 9 & 10

Application: Live Event Shows with the LowLatency RealTimeAudio Soundgrid-Protocol (f.e. Mixing Bands in the front of thousands of people, there ist no place for network-dropouts)

- Green Ethernet off

- QoS configured for RealTimeAudio

 

Our Problem:
2 Trunks (9&10) connected to the second switch / The GUI shows us Port 9 as "Alternate" and Port10 as "Main".
When we disconnect Port 10; Audio drops for 0,5 s, now Audio flows over Port 9 / When we connect Port 10 again, the connection go back to Port 10, the Audio drops again.

 

What we need is a food for thought...
- Why drops the audio, when one port will be disconnected --> 2 trunks, same audio traffic on both ports. We shouldn't hear any changes, right?
- Why the switch sets the main and alternate fallback?

 

So, I hope you have all necessary informations. 


Please note, we're audioengineers and no supertop IT-experts ;)

 

Many thanks in advance. We hope, you can help us. Greets from Germany

1 Accepted Solution

Accepted Solutions

Hey there,

sorry for those really late response.

 

We tried your solution approaches and could solve the problem with our Trunks. Unfortunatly the Soundgrid Protocol doesn't support inaudible changes, but we reached 95% of our ideas.

 

Thanks a lot, Reza!

View solution in original post

2 Replies 2

Reza Sharifi
Hall of Fame
Hall of Fame

Hi,

Our Problem:
2 Trunks (9&10) connected to the second switch / The GUI shows us Port 9 as "Alternate" and Port10 as "Main".
When we disconnect Port 10; Audio drops for 0,5 s, now Audio flows over Port 9 / When we connect Port 10 again, the connection go back to Port 10, the Audio drops again.

Since you are connecting 2 switches together with 2 ports (9&10). The Spanning tree protocol (STP) will block one of them to prevent loop on the network (correct behavior). So, one port is forwarding and the other port is blocking, and so when you disconnect the port that is forwarding, the blocked port has to go through the STP process to go from blocking to forwarding and in that process you loose you audio. So, if you don't want for this to happen, you would need to put both ports is and Portchannel or aggregation group.

I am not familiar with SG series switches, but you should be able to create a Portchannel (link aggregation group) and add both ports 9 and 10 to it on both switches. Here is a link on how to do it:

https://www.cisco.com/c/en/us/support/docs/smb/switches/cisco-350x-series-stackable-managed-switches/smb5098-configuring-link-aggregation-groups-on-the-sg350xg-and-sg550.html

HTH

Hey there,

sorry for those really late response.

 

We tried your solution approaches and could solve the problem with our Trunks. Unfortunatly the Soundgrid Protocol doesn't support inaudible changes, but we reached 95% of our ideas.

 

Thanks a lot, Reza!

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