Cisco Catalyst 4948 User Manual

Appendix B
Well-known Protocol,
Port, and Other Numbers
Refer to the following sections for explanations and listings of well-known numbers:
■ B-1: IP Protocol Numbers
■ B-2: ICMP Type and Code Numbers
■ B-3: Well-known IP Port Numbers
■ B-4: Well-Known IP Multicast Addresses
■ B-5: Ethernet Type Codes
B-1: IP Protocol Numbers
A higher-layer protocol is identified with an 8-bit field within an IPv4 packet called
Protocol. The IPv4 header format is shown in Figure B-1 with the Protocol field shaded.
Figure B-2 shows the IPv6 header format where the protocol number is stored in the
shaded Next Header field.
Well-known or assigned IP protocols are registered with the Internet Assigned Numbers
Authority (IANA). The information presented here is reproduced with permission from
the IANA. For the most current IP protocol number assignment information, refer to
www.iana.org/numbers.htm under the “Protocol Numbers” link.

Cisco Catalyst 4948 Specifications

General

Brand	Cisco
Model	Catalyst 4948
Category	Switch
Language	English