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Do the Catalyst 4500/4000 switches that run CatOS honor the incoming Class of Service (CoS) value in IEEE 802.1Q (dot1q) tags from my IP phones?

April 26, 2017catalyst catos class honor incoming run service switches

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Do the Catalyst 4500/4000 switches that run CatOS honor the incoming Class of Service (CoS) value in IEEE 802.1Q (dot1q) tags from my IP phones?

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A. Yes, Catalyst 4500/4000 switches that run CatOS do honor the incoming CoS value in the dot1q tag. Since dot1q does not tag the native VLAN, you need to use the switch-wide CoS configuration to tag such packets. These tags are retained through the switch and used in output scheduling. If the outgoing port is a trunk, the original CoS value or the new value (for packets that arrive untagged on native VLAN) is tagged in the packet.