What differentiates the HDLC header in the Cisco standard from the ISO standard?

The differentiation of the HDLC header in the Cisco standard from the ISO standard lies in the inclusion of a 'Type' field, which is used to identify the encapsulated protocol being carried in the payload of the HDLC frame. This allows devices using Cisco's implementation to recognize and process different networking protocols that might be running over the same link.

The 'Type' field is particularly useful in environments where multiple protocols coexist, providing the necessary information to determine how to handle the incoming data. This feature is instrumental for efficient routing and switching in multi-protocol networks, allowing for seamless interoperability among various network services.

In contrast, the ISO standard HDLC does not define a similar field, relying instead on a simpler structure without a protocol type identifier. Therefore, the inclusion of the 'Type' field in the Cisco HDLC frame enhances flexibility and compatibility in diverse networking scenarios.