400-007 Reviews Questions

A picture containing table Description automatically generated

IPv4:

Host Registration - IGMP

Router Registration - PIM-DM, PIM-SM, SSM, BIDIR

Inter-Domain Source Discovery - MSDP

IPv6:

Host Registration - MLD

Router Registration - PIM-SM, SSM, BIDIR

A (EIGRP summarization):Summarization reduces unnecessary routing information exchange, simplifies the routing table, and improves convergence.

D (Route leaking on London-Rome link):Route leaking allows specific prefixes (such as important routes for direct communication) to be advertised across the London-Rome link, ensuring it ' s utilized where appropriate.

Other options explained:

B: Filtering routes on Barcelona would prevent reachability unnecessarily.

C: Filtering on London-Rome link would prevent its usage entirely.

In service provider Ethernet transport environments such as VPLS, Ethernet OAM (Operations, Administration, and Maintenance) is used to provide fault detection, monitoring, and troubleshooting capabilities. The two relevant components here are:

A (Unicast heartbeat messages between MEPs): Maintenance End Points (MEPs) are configured at the edges of the OAM domain (SP-SW1 and SP-SW2). Heartbeat messages can be used to proactively monitor and detect loss of continuity between the endpoints.

B (Enable Connectivity Fault Management): CFM (IEEE 802.1ag) provides end-to-end fault detection, continuity check messages (CCMs), loopback, and link trace mechanisms that operate between MEPs at Layer 2. CFM enables proactive detection of failures and service-level assurance across the provider’s Ethernet segment.

Other options explained:

C: Upward MEPs are not applicable here since these are typically used for customer-facing or hierarchical maintenance domains.

D: E-LMI (Ethernet Local Management Interface) operates between CE and PE for service activation—not applicable for SP-SW to SP-SW fault detection across VPLS.

E: LLDP (Link Layer Discovery Protocol) is for neighbor discovery on directly connected interfaces—not suitable for end-to-end fault detection across a VPLS domain.

This design solution aligns fully with CCDE v3.1 principles for service provider Layer 2 VPN design and Ethernet OAM integration.