Exam 200-301 topic 1 question 291 discussion

I think answer is correct. Set the priority of data traffic received from the Cisco IP Phone access port: •cos value—Configure the "phone" to override the priority received from the "PC or the attached device" with the specified CoS value. The value is a number from 0 to 7, with 7 as the highest priority. The default priority is cos 0. So, If we set the value 7 here it means, port will prioritize the voice traffic over data traffic. •trust—Configure the phone access port to trust the priority received from the "PC or the attached device". When traffic from pc is trusted, it will consider both voice and data traffic as same priority. (Since voice traffic is prioritised over data traffic by default.)

Hey, I know that the answer is D, but do we have to know this type of commands for the CCNA ?

D is correct, voice is always periodized over data, trust would prioritize both same while transmitting.

Answer B: I don't trust this Phone - not family. I'll mark that PC connected to it myself and I'll even make it higher. I'll show that phone who's boss around here. Answer D: Phone is family. I will treat everything it throws at me one and the same. Whatever phone decides, it's all good. Hugs!!! XOXO

The default cos value for voice on the voice access port is 5, the default data cos is 0, so if the command interface fastethernet0/1 switchport priority extend trust is used , data cos will remain as default which is 0, on the other hand extend cos 7 would set it to 7 on the phone, whereas data cos would remain 5 making the data priority higher 7> 5, so the correct answer is C as was noted by a gentlemen everchosen13

switchport priority extend is used to configure the switch port to extend the priority markings of the incoming frames. trust in this context means that the switch will trust the priority markings set by the connected device (in this case, the IP phone). This configuration allows the switch to trust the priority markings set by the IP phone, ensuring that both voice and data packets are treated with the same priority when transmitted through the same port. This is commonly used in Quality of Service (QoS) configurations to maintain proper prioritization of traffic.

D is correct, "switchport priority extend trust" in trust mode the switch transmits frames with the same marking received on its port. Without this command, the markings would be forwarded with CoS 0, regardless of the marking received. If the question had asked to change the marking, also with the highest possible priority, then the answer would be B, "switchport priority extend cos 7" with CoS 7 transmission for all packets, regardless of the marking received.

Wondering why 100% said B is correct when it doesn't seem to according to below cisco source. D is the correct answer. Please read carefully: "Cisco IP Phone Data Traffic The switch can also process tagged data traffic ( traffic in IEEE 802.1Q or IEEE 802.1p frame types ) from the device attached to the access port on the Cisco IP Phone. You can configure Layer 2 access ports on the switch to send CDP packets that instruct the attached phone to configure the phone access port in one of these modes : - In trusted mode , all traffic received through the access port on the Cisco IP Phone passes through the phone unchanged. - In untrusted mode , all traffic in IEEE 802.1Q or IEEE 802.1p frames received through the access port on the Cisco IP Phone receive a configured Layer 2 CoS value . The default Layer 2 CoS value is 0. Untrusted mode is the default."

The switchport priority extend trust command does not configure the switch port to trust the traffic it receives from an IP phone.

B is the Answer: Step 3 switchport priority extend {cos value | trust} Set the priority of data traffic received from the Cisco IP Phone access port: •cos value—Configure the phone to override the priority received from the PC or the attached device with the specified CoS value. The value is a number from 0 to 7, with 7 as the highest priority. The default priority is cos 0. •trust—Configure the phone access port to trust the priority received from the PC or the attached device.

Switch(config)#int g0/1 Switch(config-if)#switchport priority extend trust ^ % Invalid input detected at '^' marker

"D" is 100% correct. You are not instructed to overwrite the priority received from the phone's access port. Just trust the priority received and transmit data with the same priority. A tricky question to understand.

The given answer is incorrect. C is the answer the correct Answer https://community.cisco.com/t5/switching/switchport-priority-extend-cos-0/td-p/1638603