Understanding Network Layer Data Plane

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Questions and Answers

What are the goals of Ethernet decentralized switching?

The goals of Ethernet decentralized switching are to complete input port processing at 'line speed' and to use header field values to lookup output ports using a forwarding table in input port memory.

What is the function of input port queuing in Ethernet decentralized switching?

The function of input port queuing is to manage incoming datagrams when they arrive faster than the forwarding rate into the switch fabric.

What are the functions of the network layer in the context of the given text?

The network layer performs line termination, link layer protocol (receive), lookup, forwarding, switch fabric, queueing, and bit-level reception at the physical layer.

What are the two types of forwarding mentioned in the context of Ethernet decentralized switching?

The two types of forwarding mentioned are destination-based forwarding, which forwards based only on the destination IP address (traditional), and generalized forwarding, which forwards based on any set of header field values. Signup and view all the answers

What is the purpose of using header field values in Ethernet decentralized switching?

The purpose of using header field values is to lookup output ports using a forwarding table in input port memory, following the 'match plus action' principle. Signup and view all the answers

Explain the concept of buffer management in the context of network packet scheduling.

Buffer management involves deciding which packet to add, mark to signal congestion, and which packet to drop when buffers are full. Signup and view all the answers

Describe the scheduling policy of first-come-first-served (FCFS) in packet scheduling.

FCFS, also known as First-in-first-out (FIFO), transmits packets in the order of their arrival to the output port. Signup and view all the answers

What is the priority scheduling policy and how does it work in packet scheduling?

Priority scheduling involves classifying arriving traffic and queuing by class, then sending packets from the highest priority queue that has buffered packets. FCFS is used within each priority class. Signup and view all the answers

Explain the concept of round robin (RR) scheduling in the context of packet scheduling.

Round Robin scheduling involves classifying arriving traffic, queuing by class, and cyclically scanning class queues to send one complete packet from each class in turn. Signup and view all the answers

What is weighted fair queuing (WFQ) and how does it differ from Round Robin scheduling?

Weighted Fair Queuing (WFQ) is a generalized form of Round Robin scheduling where each class has a weight and gets a weighted amount of service in each cycle. It provides a minimum bandwidth guarantee per traffic class. Signup and view all the answers

Study Notes

Network Layer Overview

The network layer is divided into two planes: data plane and control plane
The data plane focuses on instantiating and implementing network protocols, such as IP and NAT
The control plane manages the router's software and operates in a millisecond time frame

Router Architecture

A generic router architecture consists of:
- Input ports
- Switching fabric
- Output ports
The routing processor operates in the control plane and manages the router's software
The forwarding data plane operates in a nanosecond timeframe and handles high-speed switching

Input Port Functions

Receive incoming packets through line termination
Perform link layer protocol processing
Perform lookup and forwarding
Manage queueing and physical layer transmission

IP Protocol

IP is the Internet Protocol that defines the datagram format and addressing
Network Address Translation (NAT) is a key concept in IP
IPv6 is a newer version of the IP protocol

Generalized Forwarding

Generalized Forwarding is a concept that enables flexible forwarding in routers
Software-Defined Networking (SDN) is an example of generalized forwarding
OpenFlow is a protocol that enables match+action forwarding in SDN

Middleboxes

Middleboxes are specialized devices that perform specific functions in the network
Examples of middleboxes include firewalls, intrusion detection systems, and load balancers

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Description

This quiz focuses on principles behind network layer analysis, specifically the data plane. It covers topics such as IP protocol, NAT, middleboxes, network layer service models, forwarding, routing, router functioning, and addressing. The content aims to provide a comprehensive understanding of the data plane in the network layer.