Exam 300-420 topic 1 question 139 discussion

Recommendations by Cisco and the RFC. Looks like multimedia would be AF3x. https://ptgmedia.pearsoncmg.com/images/chap16_9781587144622/elementLinks/16fig04_alt.jpg

it is question, whether AF3 meen AF31 AF32 AF33, or AF3 class doesn't exist, therefore only existing DSCP would be EF

correct C

The DSCP value for Multimedia Streaming is AF3

https://www.ciscopress.com/articles/article.asp?p=2159353&seqNum=3

i go for 'C' - Official Cert Guide states 'Multimedia Streaming = AF3' (p. 311) and LLQ is too strong for Multimedia to implement (only for 'real time' like Voice or videoconferencing)

This is from Cisco Learning Space... "Broadcast video traffic should be marked to CS5 /DSCP 40" "Multimedia Streaming AF21 Per Hop Behavior"

I think that the answer is C: AF3 = multimedia streaming

I think answer is correct....Low Latency Queuing (LLQ) is the preferred queuing policy for VoIP audio. Given the stringent delay/jitter sensitive requirements of TP and the need to synchronize audio and video for CUVA, priority (LLQ) queuing is the recommended for all video traffic as well. Note that, for video, priority bandwidth is generally fudged up by 20% to account for the overhead.

C. LLQ is mainly for Voice and other Critical Controls. See the link below which states that Multimedia is AF3. https://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/Campus/Borderless_Campus_Network_1-0/Borderless_Campus_1-0_Design_Guide/BN_Campus_QoS.html

Streaming multimedia should not be on the LLQ, the LLQ is for real-time traffic. I am not very sure but I will go for CBWFQ with DCP AF2 (lower drop probability).

LLQ with EF seems way too strict for STREAMING multimedia (where one can actually take advantage of buffering). Judging by the various Cisco QoS baseline docs (even though the ones below are quite old), streaming video should be somewhere at AF3x/CS4. So I would go with C. https://www.cisco.com/en/US/technologies/tk543/tk759/technologies_white_paper0900aecd80295a9b.pdf https://community.cisco.com/t5/collaboration-voice-and-video/cisco-qos-baseline-classification-and-marking-and-mapping/ta-p/3108355