320 Chapter 5: Network Protocols
Figure 5-41 shows the format of addresses when subnetting.
Figure 5-41
Address Formats, When Subnetting Is Used
Figure 5-42 shows an example of TCP error recovery.
Figure 5-42
TCP Acknowledgment with Errors
Figure 5-43 shows a TCP connection establishment flow, which in this case is for an FTP
control connection to well-known port 21.
Figure 5-43
FTP Control Connections
Network
Host
Class A
8
x
Subnet
24 -- x
Network
Host
Class B
16
Subnet
16 -- x
x
Host
Network
Class C
x
Subnet
8 -- x
24
Web
Client
Web
Server
SEQ=1000
SEQ=2000
SEQ=3000
ACK=2000
SEQ=2000
ACK=4000
FTP Client
SYN, DPORT=21, SPORT=1030
FTP Server
SYN, ACK, DPORT=1030, SPORT=21
ACK, DPORT=21, SPORT=1030
ch05.fm Page 320 Monday, March 20, 2000 5:06 PM