Sem 2 Networking Programming Week 6 Network Layer

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is a key characteristic of IP regarding the media type?

IP can be sent over any media type (correct)

IP can only be sent over fiber media

IP is dependent on the data link layer

IP can only be sent over copper media

What is the purpose of the Maximum Transmission Unit (MTU) in the network layer?

To establish the network layer protocol

To determine the packet size

To determine the type of media used

To determine the maximum size of a packet that can be sent over a network (correct)

What happens when a packet is sent over a network with a smaller MTU?

The packet is fragmented into smaller units (correct)

The packet is discarded

The packet is routed to a different network

The packet is sent with a different protocol

What is the main difference between IPv4 and IPv6 packet fragmentation?

IPv4 packets are fragmented, while IPv6 packets are not Signup and view all the answers

What is the primary purpose of the IPv4 packet header?

To ensure the packet is sent in the correct direction Signup and view all the answers

What is the purpose of the Time to Live (TTL) field in the IPv4 packet header?

To determine the maximum number of hops a packet can take Signup and view all the answers

What is the purpose of the Header Checksum field in the IPv4 packet header?

To detect corruption in the packet Signup and view all the answers

What is the purpose of the Version field in the IPv4 packet header?

To identify the IP version (IPv4 or IPv6) Signup and view all the answers

What is the primary reason for the development of IPv6?

To overcome the limitations of IPv4, such as address depletion Signup and view all the answers

What is the size of an IPv6 address?

128 bits Signup and view all the answers

What is a benefit of IPv6 in terms of packet handling?

Simplified packet headers with fewer fields Signup and view all the answers

What is the purpose of NAT in IPv4?

To extend the life of IPv4 by allowing private addressing Signup and view all the answers

What is a limitation of IPv4 in terms of addressing?

Limited address space Signup and view all the answers

How does IPv6 address the limitation of lack of end-to-end connectivity in IPv4?

By eliminating the need for NAT Signup and view all the answers

What is the size of the IPv6 packet header?

40 bytes Signup and view all the answers

What is a benefit of IPv6 in terms of network complexity?

Reduced network complexity due to the elimination of NAT Signup and view all the answers

What is the purpose of the Traffic Class field in the IPv6 header?

To provide Quality of Service (QoS) information Signup and view all the answers

What is the function of the Flow Label field in the IPv6 header?

To inform devices to handle identical flow labels the same way Signup and view all the answers

What is the purpose of the Next Header field in the IPv6 header?

To identify the next level protocol Signup and view all the answers

What is the length of the Payload Length field in the IPv6 header?

16 bits Signup and view all the answers

What is the main difference between the IPv4 and IPv6 packet headers?

The presence of a Flow Label field Signup and view all the answers

What is the purpose of the Version field in the IPv6 header?

To identify the version of the IP protocol Signup and view all the answers

What is the benefit of removing certain fields from the IPv4 packet header in IPv6?

Improved performance Signup and view all the answers

Which of the following fields is NOT present in the IPv6 packet header?

Header Checksum Signup and view all the answers

What is the purpose of the Hop Limit field in an IPv6 packet?

To replace the TTL field and count the number of hops Signup and view all the answers

What is the main difference between IPv4 and IPv6 in terms of packet fragmentation?

Routers fragment IPv4 packets, but not IPv6 packets Signup and view all the answers

What is the role of extension headers in an IPv6 packet?

To provide optional network layer information Signup and view all the answers

How does a host determine whether the destination is local or remote in IPv6?

Using the network address and prefix advertised by the local router Signup and view all the answers

What is the purpose of the default gateway in host routing?

To accept data from the LAN and forward traffic off the LAN Signup and view all the answers

What is the characteristic of the source IPv6 address in an IPv6 packet?

It is a 128-bit address Signup and view all the answers

Where are extension headers placed in an IPv6 packet?

Between the IPv6 header and the payload Signup and view all the answers

What is the role of a host device in routing decisions?

To create packets and determine whether the destination is local or remote Signup and view all the answers

What is the primary function of the Network Layer?

To allow end devices to exchange data Signup and view all the answers

What is the consequence of IP being a connectionless protocol?

The destination receives the packet when it arrives, but no pre-notifications are sent Signup and view all the answers

What is the purpose of IP encapsulation?

To encapsulate the transport layer segment Signup and view all the answers

What is a characteristic of IP?

Best Effort and Media Independent Signup and view all the answers

What is the result of IP being a Best Effort protocol?

IP has reduced overhead since there is no mechanism to resend data Signup and view all the answers

What happens to the IP packet when it is examined by all layer 3 devices as it traverses the network?

The packet is examined by all layer 3 devices as it traverses the network Signup and view all the answers

What is a consequence of IP being Media Independent?

IP must rely on other protocols for these functions Signup and view all the answers

What is the primary difference between IPv4 and IPv6?

They are principle network layer communication protocols Signup and view all the answers

Study Notes

IPv6 Packet Header

The IPv6 packet header has significant fields, including:
Version: 4-bit field indicating IPv6
Traffic Class: equivalent to DiffServ - DS field
Flow Label: 20-bit field informing devices to handle identical flow labels the same way
Payload Length: 16-bit field indicating the length of the data portion or payload
Next Header: identifies the next level protocol, such as ICMP, TCP, or UDP

Media Independence

IP is media independent, meaning it can be sent over any media type (copper, fiber, or wireless)
The network layer establishes the Maximum Transmission Unit (MTU) based on control information from the data link layer
Fragmentation occurs when Layer 3 splits the IPv4 packet into smaller units, causing latency; IPv6 does not fragment packets

IPv4 Packet Header

The IPv4 packet header has significant fields, including:
Version: 4-bit field indicating IPv4
Differentiated Services: equivalent to DiffServ - DS field or the older IntServ - ToS or Type of Service
Header Checksum: detects corruption in the IPv4 header
Time to Live: Layer 3 hop count; when it reaches zero, the router discards the packet
Protocol: identifies the next level protocol, such as ICMP, TCP, or UDP
Source IPv4 Address: 32-bit source address
Destination IPv4 Address: 32-bit destination address

Limitations of IPv4

IPv4 has three major limitations:
IPv4 address depletion
Lack of end-to-end connectivity due to private addressing and NAT
Increased network complexity due to NAT

IPv6 Overview

IPv6 was developed by the Internet Engineering Task Force (IETF) to overcome the limitations of IPv4
Improvements in IPv6 include:
Increased address space based on 128-bit addresses
Simplified header with fewer fields
Elimination of the need for NAT due to the huge amount of available addresses

IPv6 Packet Header Fields

The IPv6 header is simplified and fixed at 40 bytes or octets long
Several IPv4 fields were removed to improve performance, including:
Flag
Fragment Offset
Header Checksum
New fields in the IPv6 header include:
Hop Limit: replaces TTL field, Layer 3 hop count
Source IPv6 Address: 128-bit source address
Destination IPv6 Address: 128-bit destination address

Extension Headers

IPv6 packets can contain extension headers (EH) that provide optional network layer information
EH characteristics:
Are optional
Are placed between the IPv6 header and the payload
May be used for fragmentation, security, mobility support, etc.

Host Routing and Forwarding

Packets are always created at the source
Each host device creates its own routing table
A host can send packets to itself, local hosts, or remote hosts
The source device determines whether the destination is local or remote
The method of determination depends on the IP version:
IPv4: uses IP address and subnet mask
IPv6: uses the network address and prefix advertised by the local router

Default Gateway

A router or layer 3 switch can be a default gateway
Features of a default gateway (DGW) include:
Having an IP address in the same range as the rest of the LAN
Accepting data from the LAN and forwarding traffic off the LAN

Network Layer Characteristics

The network layer provides services to allow end devices to exchange data
IP version 4 (IPv4) and IP version 6 (IPv6) are the principle network layer communication protocols
The network layer performs four basic operations:
Addressing end devices
Encapsulation
Routing
De-encapsulation

IP Encapsulation

IP encapsulates the transport layer segment
The IP packet is examined by all layer 3 devices as it traverses the network
The IP addressing does not change from source to destination

Characteristics of IP

IP is meant to have low overhead and can be described as:
Connectionless
Best Effort
Media Independent

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz covers the differences between IPv4 and IPv6 packet headers, including removed fields in IPv4 and significant fields in IPv6. Test your knowledge of computer networking!