A recursive resolver is responsible for resolving DNS queries on behalf of clients. It performs the entire process of DNS resolution, starting from querying authoritative name servers to returning the IP address associated with a domain.

The primary purpose of NAT (Network Address Translation) in a home network is to translate private IP addresses used within the local network into a single public IP address that is used for communication with external networks, like the internet. This allows multiple devices within the home network to share a single public IP address, providing a layer of security and conserving IP address resources.

When a segment arrives out of order due to network congestion, it is typically held in a buffer until the missing segments arrive. This buffer helps reassemble the data in the correct order before delivering it to the application layer to prevent data corruption or loss.

TCP (Transmission Control Protocol) - TCP is responsible for ensuring that data packets are delivered in the correct sequence and without errors. It provides error-checking, sequencing, and flow control during data transmission, making it a reliable choice for applications that require data integrity.

The designated router (DR) in OSPF (Open Shortest Path First) is responsible for advertising Link State Advertisements (LSAs) to other routers within the same OSPF area. It helps reduce the flooding of LSAs and optimizes the OSPF network by centralizing LSA update distribution.

OSPF (Open Shortest Path First) is the most appropriate routing protocol in this case. OSPF is specifically designed for large internal networks and offers scalability and efficient handling of topology changes within areas. It's widely used for internal routing within organizations.

ARP (Address Resolution Protocol) is used to resolve an IP address into a MAC address within a local network. When a device needs to communicate with another device on the same local network, it uses ARP to find the MAC address associated with the destination IP address.

When a user connects to a remote network in a way that makes it seem as if they are directly connected to the network's private internal system, they are using a VPN (Virtual Private Network). A VPN creates a secure, encrypted tunnel over an untrusted network (like the internet) to provide remote access with the appearance of being locally connected.

Immunity to Eavesdropping - Fiber optic cables offer a high level of data security because they transmit data as light pulses, and it's extremely difficult to intercept these signals without disrupting the communication. Unlike other mediums where electromagnetic signals can be intercepted, fiber optic cables are more secure against eavesdropping.

Virtual LAN (VLAN) is a solution that can segregate a network into smaller, isolated segments, even if they share the same physical infrastructure. This helps reduce broadcast traffic and allows different departments to communicate efficiently while maintaining network security.

BGP (Border Gateway Protocol) is the protocol John is likely considering. BGP is well-known for its route stability and supports complex policy-based routing decisions. It's a good choice for networks where route stability is crucial.

The Application, Presentation, and Session layers of the OSI model correspond to the Application layer in the TCP/IP model. The Application layer in the TCP/IP model is responsible for providing network services directly to applications. It serves as the interface between software applications and the network stack, handling tasks such as data encryption and decryption, data compression, and application-level protocols.