Cisco 300-420 Exam Dumps

BIDIR-PIM is the correct multicast mode for a video conferencing environment with numerous dispersed senders and receivers. Bidirectional PIM is designed for many-to-many multicast applications where receivers may also transmit and where maintaining per-source trees would create unnecessary state and control-plane overhead. Instead of building a shortest-path tree for every source, BIDIR-PIM uses a shared tree rooted at the rendezvous point and forwards traffic bidirectionally. This makes it attractive for collaborative applications and conferencing scenarios with many active participants. MP-BGP can carry multicast VPN or multicast routing information in service-provider designs, but it is not itself the multicast forwarding mode for this requirement. MSDP is used to exchange source information between PIM-SM domains, not to optimize many-to-many forwarding within the multicast design. IGMPv2 handles host membership signaling on local segments and does not provide the routed multicast mode. Reference topics: BIDIR-PIM, many-to-many multicast, shared tree, video conferencing multicast, PIM design.

Internal border and anywhere border are valid Cisco SD-Access border node types. A border node connects the SD-Access fabric to networks outside the fabric, but different border roles are used depending on what external reachability is required. An internal border provides connectivity to known internal networks such as shared services, data center prefixes, or enterprise routes that should be reachable from inside the fabric. An anywhere border combines external and internal border behavior and can provide broader exit capabilities depending on the fabric design. The commonly described border roles also include external border, which provides default or Internet-facing exit from the fabric, but that option is not available in the listed choices. ''Extended border,'' ''edge border,'' and ''intermediate border'' are not the correct named border node types. The answer is therefore internal border and anywhere border. Border placement is a major design decision because it influences route advertisement, VN-to-VRF mapping, external connectivity, transit behavior, and failure-domain boundaries for SD-Access fabrics.

Bidirectional PIM is the best fit for this multicast design because the application is many-to-many and has a manageable but meaningful number of multicast sources. Cisco describes BIDIR-PIM as a multicast mode designed for many-to-many applications where sources and receivers can be widely distributed. Unlike classic PIM sparse mode, BIDIR-PIM does not build source-specific shortest-path trees for each active source. Instead, traffic uses a shared bidirectional tree rooted at the rendezvous point, which reduces multicast state in the network and improves scale when many sources may send to the same group. Source-Specific Multicast is optimized for one-to-many distribution where receivers know the source and join an (S,G) channel; it is not the natural many-to-many choice. Any Source Multicast can support many-to-many traffic but usually creates more state because source trees may be built. Multicast VPN is a transport/service architecture, not the specific multicast mode requested. Reference topics: BIDIR-PIM, many-to-many multicast, shared trees, RP-based forwarding, multicast state scaling.

BGP community is the correct attribute because it can support both policy requirements through coordination with the service provider. Communities are route tags that an upstream provider can match to apply routing policy, such as adjusting local preference to influence which dual-homed provider link is preferred for inbound traffic. Communities also include well-known values used to constrain route propagation. Cisco documents no-export as a community that prevents a route from being advertised outside the receiving AS, and no-advertise as a community that prevents advertisement to any peer. This directly matches the requirement that several customer-advertised networks must propagate no further. MED can influence inbound path selection in some dual-link designs, but it does not provide the propagation-control function. AS-path prepending can influence inbound traffic but is less precise and again does not solve the no-further-advertisement requirement. Local preference is normally applied inside an AS, not directly by the customer to external peers. Reference topics: BGP communities, no-export, no-advertise, provider policy, inbound traffic engineering.

A policy-based IPsec tunnel with static routing is the simplest secure design for connecting two hosts in two companies when no additional future connectivity is planned. The requirement is narrow: one host in Company A must communicate with one host in Company B over a single encrypted Internet connection. Policy-based IPsec is straightforward for this type of point-to-point encryption because crypto ACLs define exactly which interesting traffic should be protected. Static routing is sufficient because there is no complex topology, no dynamic path selection requirement, and no anticipated expansion. A DMVPN design would add unnecessary NHRP, multipoint GRE, and dynamic routing complexity. A routed IPsec tunnel with OSPF is useful when many networks or dynamic route changes are expected, but it is more complex than needed. MPLS VPN with BGP would require provider service and does not meet the simple encrypted Internet connection requirement. Reference topics: site-to-site IPsec, policy-based VPN, static routing, point-to-point secure connectivity, WAN simplicity.