Assigning an 802.1p priority for a global IP-precedence classifier

If a device or application upstream of the switch sets the precedence bits in the ToS/Traffic Class byte of IPv4/IPv6 packets, you can use this global packet-marking option to prioritize packets for outbound port queues. If the outbound packets are in a tagged VLAN, this priority is carried as an 802.1p value to the adjacent downstream devices.

Syntax:

qos type-of-service ip-precedence

Causes the switch to automatically assign an 802.1p priority to all IP packets (IPv4 and IPv6) by computing a packet's 802.1p priority from the precedence bits the packet carries. This priority determines the packet's queue in the outbound port to which it is sent. If the packet leaves the switch on a tagged port, it carries the 802.1p priority with it to the next downstream device.

ToS IP Precedence Default: Disabled

no qos type-of-service

Disables all ToS classifier operation, including prioritization using the precedence bits.

show qos type-of-service

When the IP-precedence mode is enabled (or if neither Type-of-Service option is configured), this command displays the ToS configuration status. If the Diff-serv mode is enabled, codepoint data is displayed.

Using the IP-precedence classifier, prioritization of outbound packets relies on the IP-Precedence bit setting that IP packets carry with them from upstream devices and applications. To configure and verify this option:

Enabling ToS IP-precedence prioritization

To change from IP-precedence to IP-Diffserv mode, follow the procedure in Assigning a priority for a global IP-device classifier, which automatically disables IP-Precedence. To disable IP-Precedence without enabling the IP-Diffserv option, enter the no qos type-of-service command.