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Function name:
IP ToS Classification
Function description:
Another QoS function is the application of Layer 3 on network framework. We
focus on TOS field of IP header. There are three bits in TOS field. We means
bit 5~7 of TOS field that we will use. According to these 3 bits, we could
arrange 8 traffics –0 0 0, 0 0 1, 0 1 0, 0 1 1, 1 0 0, 1 0 1, 1 1 0, 1 1 1. As long
as we change bit 5~7 of TOS field of IP header, we will create the 8 traffic
packets we meant before. Moreover, we can set High priority or Low priority
for each traffic class. For instance, if we let TOS 0 0 0 be high priority and TOS
0 0 1 be Low Priority, we sent in the packets that have bit 5~7 of TOS Field
appears 0 0 0 from the port 2 and the packets that have bit 5~7 of TOS Field
appears 0 0 1 from the port 3. We let the two kinds of packets be transmitted
for port 1 until the port results in congestion. The result is that the packets will
be dropped partially from the port 3 because the packets that belong to Low
Priority.
Fig. 3-20
Parameter description:
Quality of Service (QoS) ToS Configuration:
Used for setting up the QoS in Layer 3.
Port:
User can set up the port (1~24) respectively to let TOS QoS function
work on them. If you would like to set up all ports at a time, user is also
allowed to choose “All” in the selection list to simplify the procedure of
configuration.