Network Layer Flashcards
Network Layer
It’s responsible for packet forwarding including routing through different routers, and it involves both hardware and software components
Routing:
Routing: The Network layer determines the optimal path across the network for sending packets. Routers, which operate at this layer, use protocols like OSPF (Open Shortest Path First) and BGP (Border Gateway Protocol) to exchange routing information.
Logical Addressing:
In order to send packets to a destination across multiple networks, the Network layer uses logical addressing. Each device on a network is assigned an IP (Internet Protocol) address which uniquely identifies it. This is crucial because it helps in determining where to send packets on a large network
Key Functions of the network layer
- Routing
- Logical Addressing
- Packetizing
Packetizing
The Network layer takes data segments from the Transport layer and encapsulates them into packets. Each packet includes not only the payload (the actual data) but also header information like source and destination IP addresses, which helps in the correct delivery of data.
Core Protocols and Components
IP (Internet Protocols)
ICMP (Internet Control Message Protocol)
Routers
Routing Protocols
IP
This is the primary protocol used in the Network layer. IP is responsible for addressing and routing packets between nodes. There are two versions in use, IPv4 and IPv6, which help ensure data is delivered to the correct location
ICMP (Internet Control Message Protocol):
Used for sending error messages and operational information.
Routers:
These are hardware devices or software programs that use headers and forwarding tables to determine the path for sending packets across network
Routing Protocols:
These include RIP (Routing Information Protocol), OSPF, and BGP, among others. They help routers communicate with each other to select the best paths for data transmission
Longest Prefix Match
When looking for forwarding table entry for given destination address, use longest address prefix that matches destination address
Routing
Routing is the process of selecting the best paths in a network along which to send network traffic. Routers perform this task using specific metrics to determine the optimal path for sending data from the source to the destination.
Forwarding Table:
Sometimes called a forwarding database, this table is often derived from the routing table and is used to control the actual transfer of packets across a network. Forwarding tables are optimized in hardware to make this process extremely fast
