True, and it's unavoidable.  The full name of the virtual circuit communication protocol is TCP/IP (Transmission Control Protocol over Internet Protocol).  The underlying IP is the protocol used to actually transfer the data from machine to machine.  It provides datagram service, meaning that messages may be duplicated, lost, delivered out of order, or delivered with errors.  The job of TCP is to provide virtual circuit service, meaning that messages are delivered once, in order, without errors, and reliably.

To cope with the underlying datagam service, TCP has to put error checksums on each message, assign sequence numbers to each message, and has to send an acknowledgement to the sender when a message is received.  It also has to be prepared to resend messages if there's no acknowledgement or if the ack says the message was received with errors.  You can't do all that without buffering messages.

-Paul W.