Cisco Catalyst 2000 Configuration Handbook page 302

Table B-1 Registered IP Protocol Numbers, Keywords, Names, and Associated RFCs
Keyword Protocol References
CRUDP
Combat Radio User Datagram
SSCOPMCE
IPLT
SPS
Secure Packet Shield
PIPE
Private IP Encapsulation within IP
SCTP
Stream Control Transmission Protocol
FC
Fibre Channel
Unassigned
IANA
Reserved
IANA
B-2: ICMP Type and Code Numbers
The Internet Control Message Protocol (ICMP) transports error or control messages
between routers and other devices. An ICMP message is encapsulated as the payload in
an IP packet. Figure B-3 shows the ICMP message format. Notice that in the case of an
error condition, the first 8 bytes (64 bits) of the original datagram causing the error are
included in the ICMP message. This provides the protocol and port numbers of the origi-
nal message to be seen, making troubleshooting easier.
ICMP type codes are registered with the IANA. The information presented here is repro-
duced with permission from the IANA. For the most current ICMP type code number
assignment information, refer to www.iana.org/numbers.htm under the "ICMP Type"
link.
0
ICMP type
Header & first 8 bytes of datagram that caused an error ...
Figure B-3 ICMP Message Format
Appendix B: Well-known Protocol, Port, and Other Numbers 281
Number
127
128
129
130
131
132
133
134 to 254
255
1
ICMP code
(ICMP messages that report errors only)
2 3
ICMP checksum