300-420 Exam Dumps : Designing Cisco Enterprise Networks

The correct choice is to use a distribute list outbound under the RIP process to stop EIGRP-learned prefixes from being advertised back into the RIP domain. In multipoint two-way redistribution, the major risk is route feedback: a route learned from one protocol is redistributed into another protocol and then reintroduced back into the original domain through another redistribution point. RIPv1 is especially limited because it is classful and has no native route tagging, so filtering must be carefully placed when route tags are unavailable. By filtering outbound advertisements under the RIP process, the design prevents routes that originated in the EIGRP domain from being sent into RIP where they could be relearned elsewhere and create loops or suboptimal paths. Inbound filtering on only one process does not reliably stop feedback at all redistribution points. A stronger modern design would use route tags with protocols that support them, but given the answer choices, outbound filtering toward RIP is the appropriate loop-prevention method. Reference topics: route redistribution, distribute lists, route feedback, RIPv1 limitations, EIGRP integration.

The IPv4 network 172.16.10.0/24 maps to 2001:db8:abcd::ac10:a00/120 when the IPv4 address is placed into the lowest significant bits of the IPv6 address. The calculation converts each IPv4 octet into hexadecimal: 172 is AC, 16 is 10, 10 is 0A, and 0 is 00. Combining those bytes gives AC10:0A00, displayed in IPv6 notation as ac10:a00. Because a /24 IPv4 network has 8 host bits, the mapped IPv6 network leaves the same 8 host bits, resulting in a /120 IPv6 prefix. Option B incorrectly places decimal IPv4 octets into separate IPv6 hextets and uses /96, which represents a much larger mapping block than the /24 network. Option C does not represent 172.16.10.0 in hexadecimal. Option D changes the higher-order IPv6 prefix and does not match the supplied address plan. The correct address therefore preserves the planned IPv6 prefix and embeds the IPv4 network in the low-order bits. Reference topics: IPv4-to-IPv6 address mapping, hexadecimal conversion, IPv6 prefix length, migration addressing plans.

The BGP maximum-paths feature should be included when the design goal is to install multiple eligible BGP paths in the routing table and use them for load sharing. By default, BGP selects a single best path after comparing attributes such as weight, local preference, AS path, origin, MED, eBGP over iBGP, IGP metric to next hop, and other tie breakers. If two links between autonomous systems should both carry traffic, the router must be allowed to retain more than one equal or eligible path for forwarding. The maximum-paths command enables BGP multipath installation so the data plane can load share across the available links. Update-source is used to source a BGP session from a loopback or specific interface, not to perform load sharing. Next-hop-self influences recursive reachability and next-hop handling but does not install multiple paths by itself. eBGP multihop changes TTL behavior for non-directly connected eBGP neighbors and is unrelated to load sharing over the two links. Reference topics: BGP multipath, maximum-paths, eBGP load sharing, BGP path selection, route installation.