Netgear GSM7252PS ProSafe Managed Switch Web Management User Manual - Page 400

ProSafe® Gigabit L3 Managed Stackable Switches Software Administration Manual Use the CoS Configuration page to set the class of service trust mode of an interface. Each port in the switch can be configured to trust one of the packet fields (802.1p or IP DSCP), or to not trust any packet's priority designation (untrusted mode). If the port is set to a trusted mode, it uses a mapping table appropriate for the trusted field being used. This mapping table indicates the CoS queue to which the packet should be forwarded on the appropriate egress port(s). Of course, the trusted field must exist in the packet for the mapping table to be of any use, so there are default actions performed when this is not the case. These actions involve directing the packet to a specific CoS level configured for the ingress port as a whole, based on the existing port default priority as mapped to a traffic class by the current 802.1p mapping table. Alternatively, when a port is configured as untrusted, it does not trust any incoming packet priority designation and uses the port default priority value instead. All packets arriving at the ingress of an untrusted port are directed to a specific CoS queue on the appropriate egress port(s), in accordance with the configured default priority of the ingress port. This process is also used for cases where a trusted port mapping is unable to be honored, such as when a non-IP packet arrives at a port configured to trust the IP DSCP value. To configure global CoS settings: 1. Use Global to specify all CoS configurable interfaces. The option "Global" represents the most recent global configuration settings. 2. Use Interface to specify CoS configuration settings based per-interface. 3. Use Global Trust Mode to specify whether to trust a particular packet marking at ingress. Global Trust Mode can only be one of the following. Default value is trust dot1p. • untrusted • trust dot1p • trust ip-dscp 4. Use Interface Trust Mode to specify whether to trust a particular packet marking at ingress. Interface Trust Mode can only be one of the following. Default value is untrusted. • untrusted • trust dot1p • trust ip-dscp 5. Click Cancel to cancel the configuration on the screen and reset the data on the screen to the latest value of the switch. 6. If you change any of the settings on the page, click Apply to send the updated configuration to the switch. 400 | Chapter 5. Configuring Quality of Service