A service provider hires you to design its new managed CE offering to meet these requirements: - The CEs cannot run a routing protocol with the PE - Provide the ability for equal or unequal ingress…

FlexVPN uses IKEv2 and typically requires a routing protocol such as BGP or EIGRP for dynamic spoke discovery, violating the no-routing-protocol-with-PE requirement and adding complexity to low-end CE platforms.

Point-to-point GRE requires a separate tunnel interface per site, making it operationally unscalable at 250,000 CEs, and it does not natively provide unequal ingress load balancing.

DMVPN relies on NHRP for dynamic spoke registration and typically runs a routing protocol between spokes and hub, which directly violates the requirement that CEs cannot run a routing protocol with the PE.

LISP separates the endpoint identifier (EID) from the routing locator (RLOC), so CE devices only need a default or static route toward the PE without running any dynamic routing protocol with it. Its map-server/map-resolver infrastructure scales to 250,000 or more sites, natively supports IPv6 EIDs, enables traffic engineering for equal and unequal load balancing through multiple RLOCs, and requires minimal CE-side configuration making low-cost platforms fully sufficient.