Quality of Service (QoS): Managing Bandwidth More Effectively

Using QoS Types To Configure QoS for Outbound Traffic

For example, an edge switch “A” in an untagged VLAN assigns a DSCP of 000110 on IP packets it receives on port A6, and handles the packets with high priority (7). When these packets reach interior switch “B” you want the switch to handle them with the same high priority. To enable this operation you would configure an 802.1p priority of 7 for packets received with a DSCP of 000110, and then enable diff-services:

Executingthiscommanddisplays the current ToS configuration and shows that the selected DSCP is not currently in use.

The 000110 codepoint is unused, and thus available for directly assigning an 802.1p priority without changing the packet’s DSCP.

Note: All codepoints without a “DSCP Policy” entry are available for direct 802.1p priority assignment.

Figure 6-5. Example Showing Codepoints Available for Direct 802.1p Priority Assignments

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