Exam 300-420 topic 1 question 82 discussion

https://www.cisco.com/c/en/us/td/docs/solutions/CVD/Campus/cisco-sda-design-guide.html VXLAN adds 50 bytes to the original packet. The common denominator and recommended MTU value available on devices operating in a fabric role is 9100. Network should have a minimum starting MTU of at least 1550 bytes to support the fabric overlay. MTU values between 1550 and 9100 are supported along with MTU values larger than 9100 though there may be additional configuration and limitations based on the original packet size.

https://www.cisco.com/c/en/us/td/docs/solutions/CVD/Campus/cisco-sda-design-guide.html#Underlay_Network_Design C is correct. Section SD-Access Considerations second bullet point is: ● Increase default MTU—The VXLAN header adds 50 bytes of encapsulation overhead. Enabling a campus and branch wide MTU of 9100 ensures that Ethernet jumbo frames can be transported without fragmentation inside the fabric.

not should but have

C is the right answer if it is for fabric overlay then D is the best answer

Look under "Underlay Network Design". Its the second bullet point. https://www.cisco.com/c/en/us/td/docs/solutions/CVD/Campus/cisco-sda-design-guide.html#Underlay_Network_Design

Design consideration for underlay (not overlay), C should be the right answer

I think C. If you don't increase MTU - the traffic will be fragmented because of larger VXLAN header.

I agree that a maximum of sic controlplane-NODES are supported. But six control planes? I thing the right answer is C. Due to the extra VXLAN header the default MTU size must be increased. 9100 bytes is the default for SD-ACCESS i think.

CCNP Enterprise Design ENSLD 300-420 page334 : "SD-Access fabrics can support up to six control plane nodes in a wired deployment, and WLCs and can communicate with up to four control plane nodes."

B is correct: CCNP Enterprise Design ENSLD 300-420 pag334