INTERNET PROTOCOL SUITE — Identify the outsider Which of the following is <em>not</em> part of the standard Internet (TCP/IP) protocol suite used on the public Internet?

Introduction / Context:
The Internet runs on a family of protocols commonly referred to as TCP/IP. Recognizing which protocols belong to this suite helps diagnose connectivity issues and design networks.

Given Data / Assumptions:

• We compare listed protocols with the TCP/IP stack.
• HTTP and FTP are application-layer Internet protocols; IP is the network layer; TCP is the transport layer.
• STP is a well-known networking protocol but not part of the Internet suite.

Concept / Approach:
STP stands for Spanning Tree Protocol. It operates on Ethernet switches to prevent layer-2 loops in a bridged LAN by creating a loop-free tree. While important for local switching, STP is not an Internet protocol in the TCP/IP stack used for end-to-end communication across the public Internet.

Step-by-Step Solution:
List Internet protocols among options: HTTP (application), FTP (application), IP (network), TCP (transport).Identify the remaining candidate: STP — a layer-2 bridging protocol, not part of TCP/IP.Therefore, the item that is not an Internet protocol is STP.

Verification / Alternative check:
OSI vs TCP/IP mapping shows STP at OSI Layer 2 (IEEE 802.1D), while HTTP/FTP/TCP/IP operate at higher Internet layers.

Why Other Options Are Wrong:
HTTP — used for web traffic.FTP — used for file transfer.IP — core addressing and routing protocol.TCP — reliable transport protocol.

Common Pitfalls:
Assuming “if it is a protocol, it must be an Internet protocol.” Many networking protocols exist outside the TCP/IP suite (e.g., STP, ARP at link layer, proprietary routing).

Final Answer:
STP