XNS PROTOCOL TYPES Assigned well-known socket numbers Routing Information 1 Echo 2 Router Error 3 Courier 5 [XNS038112] Time Protocol 8 [XNS088404] Experimental 40-77 Assigned internet packet types Routing Information 1 Echo 2 Error 3 Packet Exchange 4 Sequenced Packet 5 PUP 12 DoD IP 13 Experimental 20-37 [XNS038112] Xerox System Integration Standard: Courier: The Remote Procedure Call Protocol. XNSS 038112, December 1981. [XNS088404] Xerox System Integration Standard: Time Protocol. XNSS 088404, April 1984. []