Free Cisco 400-007 Actual Exam Questions - Question 4 Discussion
• The CEs cannot run a routing protocol with the PE
• Provide the ability for equal or unequal ingress load balancing in dual-homed CE scenarios.
• Provide support for IPv6 customer routes
• Scale up to 250.000 CE devices per customer.
• Provide low operational management to scale customer growth.
• Utilize low-end (inexpensive) routing platforms for CE functionality.
Which tunneling technology do you recommend?
D imo, LISP handles massive scale and IPv6 without needing CE-PE routing.
B, since GRE is simple and fits low-end CE with no routing to PE.
Makes sense that GRE fits here given the low-cost CE and no routing with PE, B.
Option B fits best since GRE is simple, lightweight, and works well on cheap CE devices.
What about option B? Point-to-point GRE seems simpler and fits low-end CEs without routing protocols.
I’m going with C on this one. DMVPN is designed to simplify management with low-end devices and doesn’t require full routing protocols between CE and PE. Plus, it supports scalable multi-homing with unequal load balancing through NHRP and can handle IPv6 routes. The scalability to 250,000 devices is a stretch but manageable with DMVPN’s hub-and-spoke plus spoke-to-spoke architecture, which helps reduce the routing overhead and keeps operational complexity low. It ticks more boxes than GRE or FlexVPN here.
D. The question emphasizes no routing protocol between CE and PE and scaling up to 250k devices, so LISP fits best. It handles large scale easily and supports IPv6 without burdening the CE with routing protocols. Also, LISP’s mapping system supports unequal ingress load balancing better than GRE or DMVPN, which rely more on routing protocols or complex setups. Plus, it works well on low-end devices since most logic is on the infrastructure side, keeping CE simple. GRE might be too basic for that scale and load balancing requirement.
Probably D. LISP can handle large scale and doesn’t require routing between CE and PE, plus it supports IPv6 and flexible load balancing, which fits the dual-homed CE scenario better than GRE.
Totally agree on dropping FlexVPN since it usually needs routing on the CE. Point-to-point GRE (B) looks solid here because it's simple, supports IPv6, and fits low-end gear without routing overhead. B
Maybe B, since point-to-point GRE is simple and doesn't require complex routing protocols on the CE. It also supports IPv6 and can run on low-end devices, matching the requirements well.
It’s D because LISP separates the locator and identifier functions, so the CE doesn’t need to run routing protocols with the PE. It also scales well for large numbers of devices and supports IPv6 natively. Plus, LISP allows for flexible load balancing with multiple ingress paths, which fits the dual-homed CE scenario. The low-end CE requirement is met since most of the complexity is offloaded to the network edge rather than the CE itself. This seems to align better with the scale and operational ease needed than GRE or DMVPN.
Not A, because FlexVPN usually involves routing protocols for dynamic path management, which the question excludes. GRE tunnels are simpler and fit better with no routing protocol on the CE side.
It’s B, since GRE is simple, supports IPv6, and fits low-end CE well without routing protocol.
C/D? CE can’t run routing with PE and needs load balancing, which DMVPN handles well. But LISP also supports big scale and IPv6. Still, DMVPN feels more suited for low-end devices and ease of management here.