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I use VPN to connect to my work network.
Could this cause slow and/or high latency internet connection for others devices on local network?
Does VPN (Cisco) in anyway change existing/default network settings?
Using anything that creates a connection between disparate network clients will change the bandwidth availability and to some degree network latency of other users on your local network. How great that change is will depend on how much data is being transferred between those disparate network clients and the bandwidth available on your local network. So running a VPN is no more or less disruptive than streaming or any other activity wi the need to continuously move data.
Your connecting to a remote VPN server, does not change network settings within your own network, but it does mean that specifically, your client device is subject to the network protocols of the VPN over the tunnelled connection. If you are experiencing any oddities when using the VPN it might be a good idea to ask your work sys-admins if there are any recommended network settings you should on your home network to minimise conflicts!