![background image](http://html1.mh-extra.com/html/patton-electronics/iplink-2821/iplink-2821_getting-started-manual_4067682098.webp)
Configuring quality of service (QoS)
98
IPLink 2800 Series Getting Started Guide
8 • Link scheduler configuration
can be used to mark a specific packet type for the other network nodes. By default the traffic-class tag is empty.
Refer to
on page 98 when using the ACL to classify traffic. It illustrates the sequence of processing
stages every routed packet passes. Only stages that have been installed in the data path with a “use profile...”
statement in the corresponding interface configuration are present. Both an input direction ACL on the receiv-
ing interface as well as an output ACL on the transmitting interface can be used to classify a packet for special
handling by the output link scheduler on the transmit interface. But as visible from the figure no ACL can be
used for an input link scheduler.
Figure 18. Packet routing in IPLink
The QoS features in IPLink are a combination of an access control list (used for packet classification) and a ser-
vice-policy profile (used by the link arbiter to define the arbitration mode and the order in which packets of
different classes are served).
Introduction to Scheduling
Scheduling essentially means to determine the order in which packets of the different traffic-classes are served.
The following sections describe the ways this arbitration can be done.
Priority
One way of ordering packets is to give priority to one traffic-class and to serve the other traffic-classes when the
first has nothing to send. IPLink uses the priority scheme to make sure that voice packets generated by the
IPLink will experience as little delay as possible.
Weighted fair queuing (WFQ)
This arbitration method assures a given minimal bandwidth for each source. An example: you specify that traf-
fic-class A gets three times the bandwidth of traffic-class B. So A will get a minimum of 75% and B will get a
minimum of 25% of the bandwidth. But if no class A packets are waiting B will get 100% of the bandwidth.
Link Scheduler
Network address
translation (NAT)
Access control
list (ACL)
IPSec encryption/
decryption
Local applications (CLI, Web Server)
To/from network port (Ethernet, PPPoE,
Frame relay, etc.)
Routing
Sequence of processing stages
passed by a routed packet
Summary of Contents for IPLink 2821
Page 4: ...Summary Table of Contents IPLink 2800 Series Getting Started Guide 4...
Page 18: ...About this guide IPLink 2800 Series Getting Started Guide 18...
Page 114: ...114 Chapter 9 LEDs status and monitoring Chapter contents Status LEDs 121...
Page 134: ...134 Appendix E IPLink 2800 Series factory configuration Chapter contents Introduction 142...
Page 136: ...136 Appendix F Installation checklist Chapter contents Introduction 144...