User manual ZYXEL GS1500-24P

[. . . ] GS1500-24P Web Managed GbE Switch Default Login Details IP Address User Name Password http://192. 168. 1. 1 admin 1234 Firmware Version 1. 00 Edition 1, 8/2009 www. zyxel. com Copyright © 2009 ZyXEL Communications Corporation About This User's Guide About This User's Guide Intended Audience This manual is intended for people who want to configure the Switch using the web configurator. Related Documentation · Support Disc Refer to the included CD for support documents. Documentation Feedback Send your comments, questions or suggestions to: techwriters@zyxel. com. tw Thank you!The Technical Writing Team, ZyXEL Communications Corp. , 6 Innovation Road II, Science-Based Industrial Park, Hsinchu, 30099, Taiwan. Need More Help? More help is available at www. zyxel. com. · Download Library Search for the latest product updates and documentation from this link. Read the Tech Doc Overview to find out how to efficiently use the User Guide and Quick Start Guide in order to better understand how to use your product. · Knowledge Base If you have a specific question about your product, the answer may be here. [. . . ] Config displays the P2P setting you have configured for the port. Actual displays the P2P setting currently in use. Edge Config displays the Edge setting you have configured for the port. Actual displays the Edge setting currently in use. 78 GS1500-24P User's Guide CHAPTER 10 QoS This chapter introduces the quality of service (QoS) parameters you can configure on the Switch. 10. 1 Overview Quality of Service (QoS) refers to both a network's ability to deliver data with minimum delay, and the networking methods used to control the use of bandwidth. Without QoS, all traffic data is equally likely to be dropped when the network is congested. This can cause a reduction in network performance and make the network inadequate for time-critical application such as video-ondemand. It can be used to prioritize source-to-destination traffic flows. All packets in the flow are given the same priority. You can configure the Switch to prioritize traffic even if the incoming packets are not marked with IEEE 802. 1p priority tags or change the existing priority tags based on the criteria you select. It also uses queuing algorithms to allow switches to maintain separate queues for packets from each individual source or flow and prevent a source from monopolizing the bandwidth. 10. 2 What You Can Do Use the Port-based Priority screen (Section 10. 4 on page 81) to assign a IEEE 802. 1p priority to packets based on the ingress (incoming) port of the packet. Use the DSCP-based Priority screen (Section 10. 5 on page 82) to assign priority to packets based on their Differentiated Services Code Points (DSCPs). Use the Policy-based Priority screens (Section 10. 6 on page 83) to classify and prioritize certain traffic flows. GS1500-24P User's Guide 79 Chapter 10 QoS Use the Priority to Queue Mapping screen (Section 10. 7 on page 86) to configure the priority level-to-physical queue mapping. Use the Packet Scheduling screen (Section 10. 8 on page 87) to set priorities for the Switch queues. This can help distribute bandwidth across the different traffic queues. 10. 3 What You Need to Know Read on for concepts on QoS that can help you configure the screens in this chapter. 10. 3. 1 DiffServ DiffServ is a class of service (CoS) model that marks packets so that they receive specific per-hop treatment at DiffServ-compliant network devices along the route based on the application types and traffic flow. Packets are marked with DiffServ Code Points (DSCPs) indicating the level of service desired. This allows the intermediary DiffServ-compliant network devices to handle the packets differently depending on the code points without the need to negotiate paths or remember state information for every flow. In addition, applications do not have to request a particular service or give advanced notice of where the traffic is going. 10. 3. 2 DSCP and Per-Hop Behavior DiffServ defines a new DS (Differentiated Services) field to replace the Type of Service (ToS) field in the IP header. The DS field contains a 6-bit DSCP field which can define up to 64 service levels and the remaining 2 bits are defined as currently unused (CU). The following figure illustrates the DS field. Figure 35 DiffServ: Differentiated Service Field DSCP (6 bits) CU (2 bits) DSCP is backward compatible with the three precedence bits in the ToS octet so that non-DiffServ compliant, ToS-enabled network device will not conflict with the DSCP mapping. The DSCP value determines the PHB (Per-Hop Behavior), that each packet gets as it is forwarded across the DiffServ network. Based on the marking rule different kinds of traffic can be marked for different priorities of forwarding. Resources can then be allocated according to the DSCP values and the configured policies. 80 GS1500-24P User's Guide Chapter 10 QoS 10. 3. 3 DiffServ Network Example The following figure depicts a DiffServ network consisting of a group of directly connected DiffServ-compliant network devices. The boundary node (A in Figure 36) in a DiffServ network classifies (marks with a DSCP value) the incoming packets into different traffic flows (Platinum, Gold, Silver, Bronze) based on the configured marking rules. [. . . ] All rights reserved. Disclaimer ZyXEL does not assume any liability arising out of the application or use of any products, or software described herein. Neither does it convey any license under its patent rights nor the patent rights of others. ZyXEL further reserves the right to make changes in any products described herein without notice. This publication is subject to change without notice. Trademarks Trademarks mentioned in this publication are used for identification purposes only and may be properties of their respective owners. Certifications Federal Communications Commission (FCC) Interference Statement This device complies with Part 15 of FCC rules. [. . . ]