The protocol-type of advanced ACL rule. 0 indicates any IPv4 or
IPv6 protocol.
<1-255> Protocol number
gre GRE tunneling(47)
icmp Internet Control Message Protocol(1)
icmpv6 Internet Control Message Protocol6(58)
igmp Internet Group Management Protocol(2)
ipinip IP in IP tunneling(4)
ospf OSPF routing protocol(89)
tcp Transmission Control Protocol (6)
udp User Datagram Protocol (17)
ipv6-ah IPv6 Authentication Header(51)
ipv6-esp IPv6 Encapsulating Security Payload(50)