Multi-protocol label switching (MPLS)-compatible network routers utilize label tags instead of which other element of a data packet?

Multi-Protocol Label Switching (MPLS) is a sophisticated protocol used in high-performance telecommunications networks. It enhances the speed and performance of data packet forwarding by using short labels instead of long network addresses, which is the main characteristic that distinguishes MPLS.

The correct answer refers to the Internet Protocol (IP) Address as the element that MPLS substitutes with label tags. In traditional IP networking, packets are routed based on their destination IP addresses, which require deeper inspection of the packet headers at each router along the path. MPLS bypasses this lengthy process by attaching a label to packets that indicates specific paths or treatments without needing to inspect the IP addresses each time.

This switching from IP addresses to labels allows for improved efficiency and faster routing, as packets can be forwarded based on their labels, which are much smaller and easier to process than full IP addresses.

In contrast, Transmission Control Protocol (TCP) Number, Source MAC Address, and Destination MAC Address are not directly replaced by the MPLS label. Each of these elements serves different functions within the OSI model. TCP numbers guide data flow control in the Transport layer, while MAC addresses are essential at the Data Link layer for local network communications. Thus, MPLS focuses on the network layer and makes