400-007 question 25: A customer is migrating from a traditional Layer 2 data center netw…

Q25Service Design

A customer is migrating from a traditional Layer 2 data center network to a new SDN-based spine-and-leaf VXLAN EVPN data center at the same location. The networks are interconnected to support Layer 2 host migration. Which activity must be completed whenever a legacy network is migrated?

← → navigate · a answer

Community votes

64% (7)

36% (4)

0% (0)

Discussion · 14

Based on the provided answers, I would almost go with C. The legacy network is already migrated, and I assume this includes all applications. In this case, it would make sense to prune the vlan from the L2 migration link to get rid of STP TCN ... . Which could still get sent due to flappigng trunk port or wrongly configured access ports in legacy. Looking for other opinions. -

B 3

Selected Answer: B B should be completed before D can take place

C 3

Selected Answer: C Network is already migrated. A, B and D (if it did make sense) already happened. So, C. Ref:https://www.cisco.com/c/en/us/td/docs/dcn/whitepapers/migrating-classic-ethernet-to-vxlan-bgp-evpn-white-paper.html "Decommission Layer 2 Interconnect Although the Layer 3 external connectivity or interconnect might remain necessary for the lifecycle of the remaining resources in the brownfield network, the Layer 2 interconnect for the first-hop gateway can be decommissioned once the workload migration is complete. It is a good practice not to have any Layer 2 interconnects if they are not required, to avoid any possibility of Layer 2 loops (Figure 31)."

I agree, everything is configured and moved, so it's time to prune.

B 2

Selected Answer: B B. his VNID gives a unique identifier for the network within the VXLAN overlay, which lets the network be identified and properly routed within the new network. This is a key step in enabling host migration at Layer 2.

I agree, it's asking when the legacy network is migrated (after all migration tasks have been finished)

C 2

Selected Answer: C C. The migrated VLAN ought to be pruned from the Layer 2 interconnects.

C 2

Selected Answer: C After all hosts are migrated to fabric, you have to prune the VLAN for fault isolation purposes.

C 2

Selected Answer: C ans is C as per https://www.cisco.com/c/en/us/td/docs/dcn/whitepapers/migrating-classic-ethernet-to-vxlan-bgp-evpn-white-paper.html

legacy ntw is not migrated

B 1

Selected Answer: B based on https://www.cisco.com/c/en/us/td/docs/dcn/whitepapers/migrating-classic-ethernet-to-vxlan-bgp-evpn-white-paper.html

C 1

Selected Answer: C Decommission Layer 2 Interconnect Although the Layer 3 external connectivity or interconnect might remain necessary for the lifecycle of the remaining resources in the brownfield network, the Layer 2 interconnect for the first-hop gateway can be decommissioned once the workload migration is complete. It is a good practice not to have any Layer 2 interconnects if they are not required, to avoid any possibility of Layer 2 loops https://www.cisco.com/c/en/us/td/docs/dcn/whitepapers/migrating-classic-ethernet-to-vxlan-bgp-evpn-white-paper.html

C 1

Selected Answer: C https://www.cisco.com/c/en/us/td/docs/dcn/whitepapers/migrating-classic-ethernet-to-vxlan-bgp-evpn-white-paper.html

B 1

Selected Answer: B No mentions the endpoints network needs to be advertised/routed. But if that is the case, pruning the VLAN from the L2 interconnect will isolate the endpoints from the rest of the network. Prudent to just go with an answer covering our question's requirements.