Network components on the client and server LAN can greatly affect the overall performance of the client-server connection. If the client is used in --iroute, other client connections to the distant LAN will also be affected.
Physical problems, such as improperly terminated fiber connections, poorly crimped RJ45 ends, and frayed or split Ethernet cables can introduce noise, resulting in packet transmission errors.
Network congestion from other LAN systems or uplink usage will not be readily apparent from within the VPN.
Prior to around 2010, Internet connections were considered more or less a simple pipe in the consumer world. If you were given a 10 Mbps (megabits per second) connection, you were allowed to use the entirety of that connection for the duration of the month (or billing cycle). Commercial connections have long been treated in an entirely different manner.
For commercial connection, hosting, or uplink, the bandwidth has been metered in some regard for quite...