Selected Answer: B I think it's B. The default route should point toward the campus core (which presumably then connects to other networks/internets). Summarization should occur at the aggregation layer and it makes sense to present the core with a downstream summary. https://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/Campus/routed-ex.html "As a design tip, unless the overall network design dictates otherwise, it is highly recommended that the network be configured with a default route (0.0.0.0) that is sourced into the core of the network, either by a group of highly available sink holes routers or by Internet DMZ routers."

Selected Answer: C I think it's C

Selected Answer: C think C

Selected Answer: B I agree with 08511d4, the correct answer is B

Selected Answer: C The aggregation layer must advertise a default route toward the access layer. Imagine Core-A is the access to MPLS and Core-B is the access to internet. If Core sends a default route you cant do traffic engineering to send internal traffic to one core and internet traffic to another core. So the best option if for the aggregation layer to send the default route toward the access layer.

A /17 summary could keep the two environments separated.

Not saying A, that looks wrong... B as suggested but should be summarized into /17s.

Selected Answer: B You advertise a default route downstream toward the aggregation layer, which then passes it to the Access Layer. You summarize the Access Layer networks UP toward the core to cut overhead in core routing tables. B

Selected Answer: C Correct answer: C - The aggregation layer must advertise a default route toward the access layer. - The VLAN subnets must be summarized into 10.0.0.0/16 at the aggregation layer and advertised to the core layer.

Selected Answer: C Changing my response, it should be C. Advertising the default route down to the access layer comes from the distribution layer in a 3-tier architecture.