Automatic Priority Queue Assignment; Token Bucket - ZyXEL Communications P-660HN-51 User Manual

Automatic Priority Queue Assignment

If you enable QoS on the Zyxel Device, the Zyxel Device can automatically base on the IEEE 802.1p
priority level, IP precedence and/or packet length to assign priority to traffic which does not match a
class.
The following table shows you the internal layer-2 and layer-3 QoS mapping on the Zyxel Device. On the
Zyxel Device, traffic assigned to higher priority queues gets through faster while traffic in lower index
queues is dropped if the network is congested.
Table 79 Internal Layer2 and Layer3 QoS Mapping
LAYER 2
PRIORITY IEEE 802.1P USER
QUEUE PRIORITY
(ETHERNET
PRIORITY)
0 1
1 2
2 0
3 3
4 4
5 5
6 6
7 7

Token Bucket

The token bucket algorithm uses tokens in a bucket to control when traffic can be transmitted. The
bucket stores tokens, each of which represents one byte. The algorithm allows bursts of up to b bytes
Chapter 17 Quality of Service (QoS)
LAYER 3
TOS (IP
PRECEDENCE)
0
0
1
2
3
4
5
6
7
P-660HN-51 User's Guide
190
IP PACKET LENGTH
DSCP
(BYTE)
000000
000000 >1100
001110 250~1100
001100
001010
001000
010110
010100
010010
010000
011110 <250
011100
011010
011000
100110
100100
100010
100000
101110
101000
110000
111000