You need to determine where the trust boundaries will be in a new Company VOIP design.
Which two statements are true about these trust boundaries? (Select two)
A.
Trust boundaries are configured in the core of the network to provide the most
efficient forwarding based upon QoS markings,
B.
Setting trust boundaries at the edge of the network allows intermediate hop devices
to administer QoS policies without detailed packet identification.
C.
Trust boundaries are used to determine which QoS mechanism will be applied to the
traffic.
D.
At the trust boundaries, the untrusted traffic will be marked with a new QoS value
appropriate for the policy in place at the point where the traffic entered the campus network.
E.
Trust boundaries define the firewall rules for QoS admission into a network.
Explanation:
The packets that enter your network or hardware can be marked into different classes; you
can define the trust boundaries in your network. You can define some devices as trusted
devices and some as untrusted devices. The packets that come from trusted devices are
considered trusted because the trusted devices classify the packets correctly. The packets
that come from untrusted devices are considered untrusted because they might not classify
the packets correctly. After you have marked the packets and defined the trust boundaries,
you can force the scheduling of the packets into different queues. These queues invoke at
the time of congestion.
Defining trust boundaries is important in your network. Setting the trust boundary at the IP
phone means that you can accept all the IP phone markings into the network without
modifications.
You should always try to do classification close to the edge of the network, for scalability.
On an IP phone, the tagged data (802.1Q/p) from the PC or any other device that is attached
to the access port of the IP phone can be trusted or untrusted. In trusted mode, the IP phone
passes all the data unchanged. In untrusted mode, the IP phone re-marks the Layer 2 CoS
value to the new value (if configured on the access layer switch) or changes it to 0, if nothing
is configured. The default is untrusted mode, which is the recommend method.
Reference: http://www.ciscopress.com/articles/article.asp?p=385336&seqNum=2