Route Tracing Program Configured to Detect Particular Network Element Making Type of Service Modification

An apparatus comprising:

• a processing element comprising a processor and a memory, the memory being coupled to the processor;
• wherein the processing element under control of the processor is operative to send route tracing messages having increasing time-to-live values and a designated type of service value from a first network element to a second network element;
• to monitor type of service values in respective time exceeded messages received from respective network elements on a given network path between the first network element and the second network element responsive to the route tracing messages;
• and to identify one or more of the network elements on the given network path that have made a modification in type of service value relative to the designated type of service value, based on the monitored type of service values in the respective time exceeded messages.

A network comprising:

• a plurality of interconnected network elements;
• wherein route tracing messages having increasing time-to-live values and a designated type of service value are sent from a first one of the network elements to a second one of the network elements;
• wherein type of service values are monitored in respective time exceeded messages received from respective ones of the network elements on a given network path between the first network element and the second network element responsive to the route tracing messages;
• and
• wherein one or more of the network elements on the given network path that have made a modification in type of service value relative to the designated type of service value are identified based on the monitored type of service values in the respective time exceeded messages.