1. A method comprising: receiving at a network element a packet including a Network Services Header (“NSH”), wherein the NSH includes an Infrastructure (“I”) flag and a service path header comprising a Service Index (“SI”), and a Service Path ID (“SPI”); determining whether the I flag is set to a first value; if the I flag is set to the first value: setting the I flag to a second value; and forwarding the packet to the service function that corresponds to the SI for processing; if the I flag is not set to the first value: decrementing the SI; and making a forwarding decision based on a new value of the SI and the SPI.