Type of Service (TOS)
Type of Service (TOS) is a parameter defined to indicate a quality of the service
desired by an application program. It is specified within a single octet of the IP
datagram header, and it is used to select Internet service. It denotes how the
Internet hosts and routers should make trade-offs between throughput, delay,
reliability, and cost.
TOS is used to identify and select the actual transmission characteristics for a
particular network, the interface, and the route to be used when routing an Internet
datagram. The TOS values are mapped into the actual TOSvalue of the particular
network a datagram is going through. All of the values are mutually exclusive.
The TOS values are defined through theAdd TCP/IP Interface (ADDTCPIFC) and
Add TCP/IP Route (ADDTCPRTE) commands. The possible selections are as
follows:
*NORMAL
Normal service is used for delivery of datagrams.
*MINDELAY
Minimize delay means that prompt delivery is important for datagrams with this
indication.
*MAXTHRPUT
Maximize throughput means that high data rate is important for datagrams with
this indication.
*MAXRLB
Maximize reliability means that a higher level of effort to ensure delivery is
important for datagrams with this indication.
*MINCOST
Minimize monetary cost means that lower cost is important for datagrams with
this indication.
Work with TCP/IP Interfaces
System: SYSNAM03
Type options, press Enter.
1=Add 2=Change 4=Remove 5=Display 9=Start 10=End
Internet Subnet Line Line
Opt Address Mask Description Type
__ _______________
__ 9.4.73.65 255.255.255.192 X25LINE *X25
__ 127.0.0.1 255.0.0.0 *LOOPBACK *NONE
__ 223.1.1.17 255.255.255.0 X25LINE *X25
F3=Exit F5=Refresh F6=Print list F11=Display interface status
F12=Cancel F17=Top F18=Bottom
Figure 62. Work with TCP/IPInterfaces Display, Multihoming
Chapter3. TCP/IP: Operation, Management, and Advanced Topics 83