KW S wrote: > > Can someone tell me what is the function of the protocol field > in the IP header. > > I get a little confused after reading from some many sources. > > Regards > kws
The Protocol field identifies the next layer, in other words the type of payload that IP is carrying. Almost every protocol has a way of identifying what the next layer is. The recipient layer uses this information to figure out which process to pass the payload to. Ethernet II has EtherType. IEEE 802.3 has the 802.2 Logical Link Control (LLC) Service Access Points (SAPs). IP has the Protocol field. UDP and TCP have port numbers. The IP Protocol field identifies the next layer as being one of these: Protocol Type in Decimal ICMP 1 IGMP 2 IP 4 (tunneling) TCP 6 IGRP 9 UDP 17 GRE 47 ESP 50 AH 51 EIGRP 88 OSPF 89 There are others but those are the most common. _______________________________ Priscilla Oppenheimer www.troubleshootingnetworks.com www.priscilla.com > > > Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=65783&t=65718 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
