IPv4 Addressing
This section introduces various IPv4 addressing techniques used in IP networks. These methods determine how IP packets are delivered—from one-to-one, one-to-many, or even one-to-nearest. They are fundamental to designing efficient and secure IP networks.
Addressing Type |
Description |
Use Case |
|---|---|---|
Anycast |
One-to-nearest delivery. Packets go to the closest destination with the shared IP. |
Load balancing, DNS, CDN nodes. |
Broadcast |
One-to-all delivery within a subnet. IPv4 supports this. |
ARP, DHCP discovery. |
CIDR |
Classless subnetting with VLSM. Replaces classful addressing. |
Route aggregation, modern IP allocation. |
Classful |
Legacy method using fixed IP blocks (A, B, C, etc.). |
Historical networks. |
Multicast |
One-to-many group communication. |
Streaming, OSPF, conferencing. |
NAT |
Private-to-public IP mapping. |
IPv4 conservation, home routers. |
Subnetting |
Divides networks into smaller subnets. |
IP management, routing control. |
Unicast |
One-to-one delivery. |
Browsing, file transfers, email. |
RFC: RFC 1546
Main Features:
One-to-nearest delivery based on routing metrics.
Multiple hosts share the same IP.
Use Cases:
DNS root servers
Content delivery networks (CDNs)
Load balancing in routing
Learn More About Anycast:
RFC: RFC 919, RFC 922
Main Features:
One-to-all within subnet.
IPv4 only; IPv6 does not support broadcast.
Use Cases:
ARP discovery
DHCPDISCOVER messages
Learn More About Broadcast:
RFC: RFC 4632
Main Features:
Replaces classful addressing.
Allows subnetting with variable-length subnet masks.
Use Cases:
Route summarization
IP space efficiency in ISPs
RFC: RFC 791 (conceptual, now obsolete)
Main Features:
Divides address space into Class A, B, C, etc.
Lacks flexibility, poor address utilization.
Use Cases:
Legacy IP networks
Educational/historical references
Learn More About Classful Addressing:
RFC: RFC 1112, RFC 5771
Main Features:
One-to-many group delivery.
More efficient than broadcast for large-scale data.
Use Cases:
IPTV
Video conferencing
OSPF, PIM routing updates
Learn More About Multicast:
RFC: RFC 3022
Main Features:
Translates private IP to public.
Extends IPv4 usability and adds a security layer.
Use Cases:
Home/enterprise firewalls
ISPs managing limited IPv4 blocks
Learn More About NAT:
RFC: RFC 950
Main Features:
Divides larger IP space into smaller, manageable parts.
Enhances routing and security.
Use Cases:
Enterprise internal segmentation
ISP hierarchical IP design
Learn More About Subnetting:
RFC: RFC 791
Main Features:
One-to-one data transfer.
Most common form of IP communication.
Use Cases:
Web browsing
Emails, file sharing
Learn More About Unicast: