Trtcm - Color-Blind Mode; Trtcm - Color-Aware Mode; Figure 120 Trtcm - Color-Blind Mode; Figure 121 Trtcm - Color-Aware Mode - ZyXEL Communications ES-3148 Series User Manual

• Green (low loss priority level) packets are forwarded.
TRTCM operates in one of two modes: color-blind or color-aware. In color-blind mode,
packets are marked based on evaluating against the PIR and CIR regardless of if they have
previously been marked or not. In the color-aware mode, packets are marked based on both
existing color and evaluation against the PIR and CIR. If the packets do not match any of
colors, then the packets proceed unchanged.

27.2.1 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 120 TRTCM - Color-blind Mode

27.2.2 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 121 TRTCM - Color-aware Mode

ES-3148 User's Guide
Exceed NO
PIR?
YES
High Packet
Loss
NO
Exceed
Red?
PIR?
YES
YES
High Packet High Packet
Loss Loss
Chapter 27 Differentiated Services
Exceed
NO
CIR?
YES
Medium Packet
Loss
NO NO
Yellow?
YES
Medium Packet
Loss
Low Packet
Loss
NO
Exceed
Low Packet
CIR? Loss
YES
Medium Packet
Loss
227