Lectures notes for 2010 - KTH

Internet Protocol version 4 (IPv4) (RFC 791)
0 7 8 15 16 23 24 31
4 bit
version
4-bit header
length
8-bit Type of Service
(TOS)
16 bit total length
16 bit identification 3-bit
flags
13 bit Fragment Offset
8-bit Time to Live (TTL) 8-bit Protocol 16 bit header checksum
32 bit Source IP address
20 bytes
32 bit Destination IP address
options (padded to 32 bit length)
data
Figure 6: IP header (see Stevens, Vol. 1, figure 3.1, pg. 34)
The fields: Version, Protocol, and Source & Destination IP addresses are all used
for demultiplexing the incoming IP packet.
We will first examine version 4, then later in the course version 6.
Maguire Internet Protocol version 4 (IPv4) (RFC 791) 1: 43 of 104
maguire@kth.se 2010.03.21 Internetworking/Internetteknik