Module Review: Network Layer
Review the core concepts of the Network Layer, including IP addressing, subnetting, routing protocols, NAT, ICMP, and the transition to the IPv6 standard.
Key Takeaways
- IP Addressing serves two main functions: Host identification and Location addressing.
- Subnetting allows us to reduce congestion, improve security, and efficiently allocate addresses.
- OSPF routes based on link state (cost/bandwidth), while BGP routes based on path vectors (policies/business rules).
- NAT enables multiple private devices to share a single public IP, mitigating IPv4 exhaustion.
- IPv6 uses 128-bit hexadecimal addresses and replaces broadcast with multicast for efficiency.
Flashcards
- CIDR: Classless Inter-Domain Routing (e.g. /24).
- Subnet Mask: Defines the boundary between network and host portions.
- NAT: Network Address Translation.
- ICMP: Protocol used for diagnostic and error reporting.
- SLAAC: Stateless Address Autoconfiguration in IPv6.
Cheat Sheet
- Private IP Ranges:
10.0.0.0-10.255.255.255172.16.0.0-172.31.255.255192.168.0.0-192.168.255.255
- IPv4 vs IPv6: 32-bit decimal vs 128-bit hexadecimal.
Quick Revision
| Protocol | Type | Purpose |
|---|---|---|
| OSPF | IGP | Shortest Path routing inside an AS |
| BGP | EGP | Policy-based routing between AS |
Next Steps
In the next module, we move to the Transport Layer, where we’ll look at how data is reliably delivered from process to process using TCP and UDP.