The IP protocol to which this rule applies. For protocol forwarding,
valid options are TCP, UDP, ESP, AH, SCTP, ICMP and L3_DEFAULT. The
valid IP protocols are different for different load balancing
products as described in Load balancing
features <https://cloud.google.com/load-balancing/docs/features#protocols_from_the_load_balancer_to_the_backends>__.
Enums
Name
Description
UNDEFINED_I_P_PROTOCOL_ENUM
A value indicating that the enum field is not set.