Echo or traceroute functionality is supported in a path spanning multiple autonomous systems (ASes) having segment routing (SR) enabled, the path including an ingress node and an egress node, by: (a) obtaining a return label stack to reach the ingress node from either (A) the egress node, or (B) a transit node in the path; (b) obtaining a label stack to reach, from the ingress node, either (A) the egress node, or (B) the transit node; (c) generating a request message including the return label stack; and (d) sending the request message towards either (A) the egress node, or (B) the transit node using the label stack. The example method may further include: (e) receiving, by either (A) the egress node, or (B) the transit node, the request message, wherein the request message includes information for performing a validity check; (f) performing a validity check using the information included in the request message to generate validity information; (g) generating a reply message including the validity information and information from the return label stack; and (h) sending the reply message towards the ingress node using information from the return label stack included in the request message.