Network Layer I & II Flashcards
Role of Network Layer?
Handles packet forwarding and routing.
What is IP?
Internet Protocol – delivers packets from source to destination.
IPv4 address length?
32 bits.
Function of a router?
Directs packets between networks based on IP addresses.
Difference between routing and forwarding?
Forwarding: moves packets; Routing: determines path.
What is fragmentation?
Breaking large packets into smaller ones for transmission.
Key components of a router?
Input ports, switching fabric, output ports.
What is the role of the control plane in the network layer?
Makes decisions about how packets should be routed.
Define CIDR.
Classless Inter-Domain Routing – allows flexible IP address allocation.
What is a subnet mask?
Defines the network and host portions of an IP address.
What is NAT?
Network Address Translation – maps private IPs to a public one.
Name a key feature of IPv6 over IPv4.
Larger address space (128-bit vs 32-bit).
What does the network layer protocol provide?
Logical communication between hosts.
How is the network layer decomposed?
Into the data plane and the control plane.
What are the functions of the data plane?
Handles per-router tasks, determining how a datagram is forwarded from input to output links.
What are the functions of the control plane?
Manages network-wide logic, using routing protocols and algorithms to route datagrams from source to destination.
How were data and control plane traditionally implemented?
Together in a monolithic manner within routers.
What does Software-Defined Networking (SDN) do?
Separates the data plane and control plane.
Where do network layer protocols run?
In every host and router.
What happens on the sending side of the network layer?
Encapsulates transport layer segments into datagrams and sends them to nearby routers.
What happens on the receiving side of the network layer?
Extracts transport layer segments from datagrams and delivers them to the transport layer.
What are the two versions of the Internet Protocol?
IPv4 and IPv6.
What is the version number field in an IPv4 datagram?
A 4-bit value specifying the IP protocol version.
Why is the header length field needed in an IPv4 datagram?
It determines where the payload begins, accounting for possible options in the datagram header.
