Method and router supporting tracing of a packet therein. A first service module receives the packet and a memory module stores a tracing extension header. The extension header comprises an identifier of a receiving service module and a tracing identifier associated with the packet. The extension is stored following reception of the packet by the first service module. Optionally, the receiving module may be the first service module that further receives the packet through a network interface module. The first service module may also generate the tracing identifier associated with the packet that uniquely identifies the tracing in the receiving module. The router may comprise a second service module and a second memory module associated thereto. The first service module may further append the tracing extension header to the packet and forwards the packet to the second service module. The second memory module may then store the extension header thereupon.