""Priscilla Oppenheimer"" wrote in message news:[EMAIL PROTECTED] > 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.
Given previous discussions here regarding "next layer" may I offer that this does not refer to the "next OSI layer" but rather something else? Otherwise we will have to go through anopther cycle of people thinking they are being told that OSPF operates at layer 4. :-> > > 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=65794&t=65718 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
