R and D guide has a lot of examples that you can look at.
So as an example in a campus environment we may have what's called conditionally trusted endpoints.
So as an example a switch would trust the markings that it receives on a port when it sees a phone through
CTP.
Phones are trusted but pieces are not.
So you'll only trust the markings that you receive when you see a phone connected to the switch.
Port so with regards to trust again the switch will trust the marking from a phone but not the marking
from a P.C..
So the trust boundary ends at the phone the switch will say I see that you're a phone so I'll trust
your costs but a piece costs will not be trusted.
So if a phone makes its traffic with a costs of 5 for the voice and signalling set to 3 that will be
accepted by the switch and may change those values to DCP a 46 and a DSP of 24.
If a P.C. sets its costs to 5 The phone will automatically reset it to 0 and the switch will also not
trust the traffic received by P.C.
they saw indeed Guide covers many switch models and many options with regards to trusting certain traffic
types but not trusting other traffic types as an example here.
The switches trusting the costs of value that it receives from a phone it uses what are called Class
maps a class map is a way to create groups or classes of traffic so in this example the order was VoIP
RTP trust is matching traffic with a DSP of 46 that's voice traffic the VoIP control trust class is
matching DSP is of 24 and 26 now based on those values something can be done with the traffic.
And in this example various queuing options are set so traffic is poor terrorised on queues on the switch
based on the traffic type that's received.
There are different ways to queue traffic on a switch.
The hardware switches will dictate how you can queue the traffic so the number of queues supported as
an example is dependent on hardware.
But essentially the idea is that you can pro try some traffic types over other traffic types by using
a queue in the same way that first class passengers approach tries to over economy class passengers.