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This R&D guide has a lot of examples that you can look at.

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So as an example, in a campus environment, we may have what's called conditionally trusted endpoints.

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So as an example, a switch would trust the markings that it receives on a port when it sees a phone

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through CDP.

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Phones are trusted, but PCs are not.

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So you'll only trust the markings that you receive when you see a phone connected to the switch port.

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So with regards to trust, again, the switch will trust the marking from a phone, but not the marking

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from a PC.

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So the trust boundary ends at the phone.

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The switch will say, I see that you're a phone, so I'll trust your costs.

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But a PC costs will not be trusted.

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So if a phone marks its traffic with a costs of five for the voice and signaling set to three, that

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will be accepted by the switch and it may change those values to a DHCP of 46 and a DHCP of 24.

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If a PC sets its costs to five, the phone will automatically reset it to zero and the switch will also

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not trust the traffic received by PC.

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The Ace R&D guide covers many switch models and many options with regards to trusting certain traffic

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types, but not trusting other traffic types.

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So as an example here, the switch is trusting the cost value that it receives from a phone.

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It uses what are called class maps.

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A class map is a way to create groups or classes of traffic.

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So in this example, the order was VoIP.

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RTP Trust is matching traffic with a DHCP of 46.

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That's voice traffic.

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The VoIP control trust class is matching DSPs of 24 and 26 now based on those values.

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Something can be done with the traffic and in this example, various queuing options are set.

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So traffic is prioritized on queues on the switch based on the traffic type that's received.

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There are different ways to queue traffic on a switch.

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The hardware of switches will dictate how you can queue the traffic, so the number of queues supported

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as an example is dependent on hardware.

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But essentially the idea is that you can try some traffic types over other traffic types by using a

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queue in the same way that first class passengers are priced over economy class passengers.