Refer to the exhibit. An engineer must maintain consistent parity between incoming and outgoing voice traffic for the trunk switch ports on a wireless controller. Which QoS value must be trusted?
To maintain consistent parity between incoming and outgoing voice traffic on the trunk switch ports of a wireless controller, the CoS (Class of Service) value must be trusted. Here's why:
CoS (802.1p):
CoS is a Layer 2 QoS marking found in the 802.1Q VLAN tag of Ethernet frames. It is used to prioritize traffic on trunk ports, which carry multiple VLANs. Since trunk ports handle VLAN-tagged traffic, trusting the CoS value ensures that voice traffic is prioritized consistently across the network.
Why CoS is Critical for Trunk Ports:
Trunk ports carry traffic for multiple VLANs, and the CoS value in the 802.1Q header is used to prioritize this traffic.
By trusting the CoS value, the wireless controller ensures that voice traffic (which is typically marked with a high CoS value, such as 5 or 6) receives the appropriate priority as it traverses the network.
Option A: DSCP (Differentiated Services Code Point):
DSCP is a Layer 3 QoS marking used in the IP header. While DSCP is important for end-to-end QoS, it is not directly relevant to trunk ports, which operate at Layer 2.
Option C: IP Precedence:
IP Precedence is an older Layer 3 QoS marking that has largely been replaced by DSCP. It is not used for prioritizing traffic on trunk ports.
Option D: 802.1p:
802.1p is actually the same as CoS. However, the term "CoS" is more commonly used in this context, making Option B the better choice.
A is correct.
https://community.cisco.com/t5/routing/when-to-use-cos-instead-of-dscp/td-p/2071708
upvoted 1 times
...
Log in to ExamTopics
Sign in:
Community vote distribution
A (35%)
C (25%)
B (20%)
Other
Most Voted
A voting comment increases the vote count for the chosen answer by one.
Upvoting a comment with a selected answer will also increase the vote count towards that answer by one.
So if you see a comment that you already agree with, you can upvote it instead of posting a new comment.
rrahim
1 week, 1 day agorrahim
1 week, 1 day ago74ca941
1 month, 3 weeks agoR3DAlert
3 months, 1 week ago