ZyXEL Communications XS-3900-48F, User Manual

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Chapter 33 Differentiated Services
XS3900-48F User’s Guide
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33.2.1 TRTCM - Color-blind Mode
All packets are evaluated against the PIR. If a packet exceeds the PIR it is marked red. Otherwise it
is evaluated against the CIR. If it exceeds the CIR then it is marked yellow. Finally, if it is below the
CIR then it is marked green.
Figure 148
TRTCM - Color-blind Mode
33.2.2 TRTCM - Color-aware Mode
In color-aware mode the evaluation of the packets uses the existing packet loss priority. TRTCM can
increase a packet loss priority of a packet but it cannot decrease it. Packets that have been
previously marked red or yellow can only be marked with an equal or higher packet loss priority.
Packets marked red (high packet loss priority) continue to be red without evaluation against the PIR
or CIR. Packets marked yellow can only be marked red or remain yellow so they are only evaluated
against the PIR. Only the packets marked green are first evaluated against the PIR and then if they
don’t exceed the PIR level are they evaluated against the CIR.
Figure 149
TRTCM - Color-aware Mode
33.3 Activating DiffServ
Activate DiffServ to apply marking rules or IEEE 802.1p priority mapping on the selected port(s).
Exceed
PIR?
High Packet
Loss
Exceed
CIR?
Medium Packet
Loss
NO
YES
NO
YES
Low Packet
Loss
Exceed
PIR?
High Packet
Loss
Exceed
CIR?
Medium Packet
Loss
NO
YES
NO
YES
Low Packet
Loss
High Packet
Loss
NO
YES
Red? Yellow?
Medium Packet
Loss
NO
YES