VIAVI TestCenter Anywhere (on Azure) - Why does my STCa ports disconnect from the GUI ~5 minutes after they've been reserved.

VIAVI TestCenter Anywhere (on Azure) - Why does my STCa ports disconnect from the GUI ~5 minutes after they've been reserved.

This issue was caused because the Azure load balancer (or instance level tcp timeout) has a  default TCP idle session timeout of around 4 minutes. STC has 2 active TCP sessions to the control software.  The first TCP session is used to connect at the “chassis-level" (reserving ports, getting system info etc.).  The second TCP session is used for "port-level" communication (configuring devices, stream, protocol, results, etc.).  Once the user reserves the ports the “chassis” level connection is not used very frequently so the Azure load balancer may detect the session is idle and stop supporting it which will cause a communication error the next time the control software needs to use the TCP session. this issue was corrected in the STC 5.03 release on all STC Virtual and Anywhere images.  The fix enables TCP keep alive messages on all TCP sessions to STCv/STCA so no TCP sessions should timeout One workaround for STC releases earlier that 5.03, is to change the TCP keepalive timeout at the O/S level: https://serverfault.com/questions/661704/azure-closing-idle-network-connections Add the following changes to the /etc/sysctl.conf file: net.ipv4.tcp_keepalive_time = 60 net.ipv4.tcp_keepalive_intvl = 60  Then reboot the STCa O/S, and start up the STCa instance.   Another workaround is change the TCP timeout on the Azure load balancer or Instance level TCP options https://docs.microsoft.com/en-us/azure/load-balancer/load-balancer-tcp-idle-timeout   Configure the TCP timeout for your instance-level public IP to 30 minutes $publicIP = Get-AzPublicIpAddress -Name MyPublicIP -ResourceGroupName MyResourceGroup $publicIP.IdleTimeoutInMinutes = "30" Set-AzPublicIpAddress -PublicIpAddress $publicIP IdleTimeoutInMinutes is optional. If it isn't set, the default timeout is 4 minutes. The acceptable timeout range is 4 to 30 minutes. This is only needed as a workaround if you don’t want to change anything on Linux side. We only need somewhere between 5-10 min, but safer to set it to the max.