Free 300-510 sample questions

Correct answer: PIMv2 Bootstrap Router (BSR) with multiple Candidate-RPs configured with the same priority.

PIMv2 Bootstrap Router (BSR) is an IETF standard (RFC 5059) and is supported by multiple vendors, making it ideal for a multi-vendor environment. Configuring multiple Candidate-RPs with the same priority allows for load balancing of multicast groups across the RPs using a hash algorithm, providing redundancy. Auto-RP is a Cisco-proprietary mechanism. Anycast RP with MSDP is a valid redundancy solution but is more complex to implement than BSR. Static RP configuration does not provide dynamic discovery or inherent redundancy.

Correct answer: router isis CORE address-family ipv4 unicast summary-prefix 10.10.0.0/16 level-1 into-level-2

In IS-IS on IOS XR, summarization from a Level 1 area into Level 2 is configured on the L1/L2 border router under the IS-IS process and the appropriate address family. The `summary-prefix 10.10.0.0/16 level-1 into-level-2` command specifically instructs the router to summarize prefixes learned via Level 1 and advertise this summary into the Level 2 domain. The other options use incorrect syntax or commands (`area-range` is for OSPF) or lack the required direction (`level-1 into-level-2`).

Correct answer: Set a higher Local Preference value for routes learned over the 10Gbps link.

Local Preference is the correct attribute for influencing outbound traffic path selection within a single AS. It is evaluated before AS path length in the BGP best path selection algorithm. By setting a higher Local Preference for the routes received over the preferred 10Gbps link, all routers within the provider's AS will choose that path to reach the customer prefix. MED is used to influence how other ASes enter the provider's network. AS path prepending influences inbound traffic from other ASes. Weight is local to a single router and not propagated, so it would not create a consistent policy across the AS.

Correct answer: Segment Routing Mapping Server (SRMS)

The Segment Routing Mapping Server (SRMS) is the correct component for LDP and SR interworking. Its primary role is to advertise mappings between SR Prefix-SIDs and prefixes to LDP-only nodes. It effectively translates SR information into a format that LDP speakers can understand, allowing them to build LSPs towards destinations in the SR domain. A PCE is used for path computation, SRGB is the global block of labels for SR, and TI-LFA is a fast reroute mechanism.

Correct answers: Mismatched interface MTU values; Mismatched OSPF area types (e.g., standard vs. stub)

Correct answer: True

True. The peering between member-ASNs inside a BGP confederation is known as an 'internal' eBGP (ceBGP) session. While it behaves like eBGP in terms of AS_PATH, it is designed to act like iBGP for attribute propagation. This means attributes like MED, Local Preference, and communities are carried unmodified between the member-ASNs, preserving the original path information throughout the confederation.

Correct answer: Match: destination-address 198.51.100.50/32, destination-port 53, protocol UDP; Action: traffic-rate 0

BGP FlowSpec rules consist of match criteria and an action. To mitigate an attack targeting a server, the match criteria must identify the destination address (the server), the destination port, and the protocol. The correct action to drop the traffic is to set the traffic-rate to 0. Therefore, matching destination-address 198.51.100.50/32, destination-port 53, and protocol UDP with an action of `traffic-rate 0` is the correct rule. Matching the source address would block traffic from the server, not to it. `redirect-to-vrf` is for traffic redirection, and `traffic-marking` changes DSCP values, neither of which drops the traffic.

Correct answers: A flexible algorithm definition (FAD) under the IS-IS process to specify the metric type and constraints.; Advertisement of the flexible algorithm participation in the IS-IS router capability TLV.; An SRv6 locator with a specific function code for the flexible algorithm.

Correct answer: BGP Route Dampening

BGP Route Dampening is the feature specifically designed to penalize and suppress unstable (flapping) routes. It assigns a penalty to a route each time it flaps. When the cumulative penalty exceeds a `suppress-limit`, the route is dampened (suppressed). The penalty value then decays over a configurable `half-life` time, and the route is un-suppressed once the penalty drops below a `reuse-limit`. This matches the requirement to suppress excessively flapping routes for a period of time.

Correct answer: Mapping of Address and Port with Translation (MAP-T)

MAP-T is a stateless IPv4/IPv6 translation mechanism that embeds IPv4 address and port information into an IPv6 address. This allows for direct translation between IPv4 and IPv6 packets without maintaining state on the translator, making it highly scalable for service provider environments. NAT64 is a stateful mechanism. Static tunnels are not a translation mechanism, and 6to4 is another tunneling technology that doesn't fit the stateless translation requirement described.