Chapter 10 Quality of Service (QoS)
VSG1435-B101 Series User’s Guide
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All packets are evaluated against the CBS. If a packet does not exceed the CBS it
is marked green. Otherwise it is evaluated against the EBS. If it is below the EBS
then it is marked yellow. If it exceeds the EBS then it is marked red.
The following shows how tokens work with incoming packets in srTCM:
• A packet arrives. The packet is marked green and can be transmitted if the
number of tokens in the CBS bucket is equal to or greater than the size of the
packet (in bytes).
• After a packet is transmitted, a number of tokens corresponding to the packet
size is removed from the CBS bucket.
• If there are not enough tokens in the CBS bucket, the ZyXEL Device checks the
EBS bucket. The packet is marked yellow if there are sufficient tokens in the
EBS bucket. Otherwise, the packet is marked red. No tokens are removed if the
packet is dropped.
Two Rate Three Color Marker
The Two Rate Three Color Marker (trTCM, defined in RFC 2698) is a type of traffic
policing that identifies packets by comparing them to two user-defined rates: the
Committed Information Rate (CIR) and the Peak Information Rate (PIR). The CIR
specifies the average rate at which packets are admitted to the network. The PIR
is greater than or equal to the CIR. CIR and PIR values are based on the
guaranteed and maximum bandwidth respectively as negotiated between a
service provider and client.
The trTCM evaluates incoming packets and marks them with one of three colors
which refer to packet loss priority levels. High packet loss priority level is referred
to as red, medium is referred to as yellow and low is referred to as green.
The trTCM is based on the token bucket filter and has two token buckets
(Committed Burst Size (CBS) and Peak Burst Size (PBS)). Tokens are generated
and added into the two buckets at the CIR and PIR respectively.
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.
The following shows how tokens work with incoming packets in trTCM:
• A packet arrives. If the number of tokens in the PBS bucket is less than the size
of the packet (in bytes), the packet is marked red and may be dropped
regardless of the CBS bucket. No tokens are removed if the packet is dropped.
• If the PBS bucket has enough tokens, the ZyXEL Device checks the CBS bucket.
The packet is marked green and can be transmitted if the number of tokens in
the CBS bucket is equal to or greater than the size of the packet (in bytes).
Otherwise, the packet is marked yellow.
Summary of Contents for VSG1435-B101 - V1.10
Page 2: ......
Page 8: ...Safety Warnings VSG1435 B101 Series User s Guide 8 ...
Page 10: ...Contents Overview VSG1435 B101 Series User s Guide 10 ...
Page 20: ...Table of Contents VSG1435 B101 Series User s Guide 20 ...
Page 21: ...21 PART I User s Guide ...
Page 22: ...22 ...
Page 42: ...Chapter 2 The Web Configurator VSG1435 B101 Series User s Guide 42 ...
Page 71: ...71 PART II Technical Reference ...
Page 72: ...72 ...
Page 78: ...Chapter 5 Network Map and Status Screens VSG1435 B101 Series User s Guide 78 ...
Page 150: ...Chapter 8 Home Networking VSG1435 B101 Series User s Guide 150 ...
Page 154: ...Chapter 9 Static Routing VSG1435 B101 Series User s Guide 154 ...
Page 178: ...Chapter 11 Policy Forwarding VSG1435 B101 Series User s Guide 178 ...
Page 196: ...Chapter 12 Network Address Translation NAT VSG1435 B101 Series User s Guide 196 ...
Page 202: ...Chapter 13 Dynamic DNS Setup VSG1435 B101 Series User s Guide 202 ...
Page 228: ...Chapter 16 Firewall VSG1435 B101 Series User s Guide 228 ...
Page 234: ...Chapter 18 Parental Control VSG1435 B101 Series User s Guide 234 ...
Page 282: ...Chapter 25 Traffic Status VSG1435 B101 Series User s Guide 282 ...
Page 286: ...Chapter 26 IGMP Status VSG1435 B101 Series User s Guide 286 ...
Page 294: ...Chapter 28 Remote Management VSG1435 B101 Series User s Guide 294 ...
Page 298: ...Chapter 29 Time Settings VSG1435 B101 Series User s Guide 298 ...
Page 302: ...Chapter 30 Logs Setting VSG1435 B101 Series User s Guide 302 ...
Page 318: ...Chapter 34 Troubleshooting VSG1435 B101 Series User s Guide 318 ...
Page 348: ...Appendix A Setting up Your Computer s IP Address VSG1435 B101 Series User s Guide 348 ...
Page 358: ...Appendix B IP Addresses and Subnetting VSG1435 B101 Series User s Guide 358 ...
Page 384: ...Appendix D Wireless LANs VSG1435 B101 Series User s Guide 384 ...