istio.io/content/help/faq/traffic-management/naming-port-convention.md

title	weight
What is the naming convention for port name inside my application deployment file?	50

Named ports: Service ports must be named.

The port names must be of the form protocol-suffix with grpc, http, http2, https, mongo, redis, tcp, tls or udp as the protocol in order to take advantage of Istio’s routing features.

For example, name: http2-foo or name: http are valid port names, but name: http2foo is not. If the port name does not begin with a recognized prefix or if the port is unnamed, traffic on the port will be treated as plain TCP traffic (unless the port explicitly uses Protocol: UDP to signify a UDP port).