What is a DHCP reservation (static DHCP mapping) and what advantage does it have over manually configuring a static IP on a device?

• A.A DHCP reservation is a backup DHCP scope that activates when the primary scope is exhausted; EDNS0 extends DNS by fragmenting every response into 512-byte chunks. DHCP leases are permanent by design; renewal only occurs after a reboot. MDNS resolves names through the default gateway's proxy cache on port 53. A lame delegation is a record whose TTL exceeds the parent zone's serial
• B.A DHCP reservation encrypts the IP assignment using the device's MAC address as a key; an SRV record maps a service to a URL, replacing the older TXT format. Split-horizon DNS answers every query with both the internal and external address. Reverse DNS lookups use the arpa-addr.in domain and TXT records. The DHCP DORA exchange ends with the client broadcasting an acknowledgment to the server
• C.DHCP reservations replace static routes in the routing table for specific devices
• D.A DHCP reservation maps a specific MAC address to a fixed IP address on the DHCP server. The device always receives the same IP via DHCP. Advantage: all IP settings (gateway, DNS, subnet mask, DHCP options) are centrally managed on the DHCP server - no manual configuration on the device. Device moves to a new subnet → update reservation on the server, not on the device