The Network Layer provides ________ to allow end devices to exchange data.

These are the principle network layer communication protocols:

Uses IPv4 and IPv6 at the same time.

The network layer performs four basic operations:

Process of accepting an incoming frame and forwarding it to its appropriate destination (depending on its Routing table)

Are these different network portions?

- 192.168.32.11

- 192.168.36.5

IP packet does not encapsulate the transport layer segment.

IP can use either an IPv4 or IPv6 packet

- and it not impact the _______ segment (since it only affects the addressing).

IP packet will be examined by all layer 3 devices as it traverses the network.

- So it can know the destination.

The IP addressing changes from source to destination.

(Additional address are added though, so it can help that packet to reach the destination.)

Translation of IPv4 private address to public address.

- Since there is a depletion of IPv4 address.

- It also adds a layer of security to the private network.

IP is meant to have ______________.

IP may be described as:

IP does not establish a connection with the destination before sending the packet.

Ex: It does not notify the receiver before sending the email.

There is control information needed in IP

(synchronizations, acknowledgments, etc.).

The destination will receive the packet when it arrives, but no pre-notifications are sent by IP.

[IP is considered unreliable protocol]

To make it reliable or if there is a need for connection-oriented traffic, then another protocol will handle this:

IP will not guarantee delivery of the packet.

IP has reduced overhead since there is no mechanism to resend data that is not received.

IP has increased overhead since there is a mechanism to resend data that is not received.

IP does not expect acknowledgments.

IP knows if the other device is operational or if it received the packet.

IP does not expect acknowledgments.

IP cannot manage or fix undelivered or corrupt packets.

- IP cannot retransmit after an error.

- IP cannot realign out of sequence

packets.

Thus, IP must rely on other protocols for these functions.

IP does not concern itself with the type of frame required at the data link layer or the media type at the physical layer.

Ex: copper, fiber, or wireless.

The ___________ will establish the Maximum Transmission Unit (MTU).

___________ receives this from control information sent by the data link layer.

The network then establishes the MTU size.

_______________ is when Layer 3 splits the IPv4 packet into smaller units.

Maximum size = MTU (___________________

Fragmenting does not cause latency.

Is the primary communication protocol for the network layer.

The network header ensures the packet is sent in the correct direction (to the destination).

The network header does not contain information for network layer processing in various fields.

The information in the network header is used by all Layer 3 devices that handle the packet.

Ex: 20 routers will use IPv4 header to find the destination.

IPv4 Packet Header Fields include:

1. Version

2-5. ?????????

6. Source IPv4 Address

7. Destination IPv4 Address

[IPv4 Packet Header Fields]

This will be for v4, as opposed to v6

(4 bit field = "0100")

[IPv4 Packet Header Fields]

Used for QoS.

DiffServ – DS field or the older IntServ – ToS or Type of Service.

[IPv4 Packet Header Fields]

Detect corruption in the IPv4 header.

[IPv4 Packet Header Fields]

Layer 3 hop count. When it becomes zero the router will discard the packet.

[IPv4 Packet Header Fields]

I.D.s next level protocol: ICMP, TCP, UDP, etc.

The Initial value of TTL IS ______.

- Each router it enters, it decrements.

- If it becomes zero and it did not reach the destination, it won't reach it anymore.

255.255.0.0

( ___ bits are turned on)

255.255.255.0

( ___ bits are turned on)

255.255.255.252

- Classless

- Used between routers.

If you are connecting a router to a router, use this so it prevents the wastage of IP address since only two of them are connected.

Every interface of a router is considered a network. (Even if its just a PC)

Ex: 3 networks in the illustration

IPv4 has three major limitations:

We have basically run out of IPv4 addressing.

There are 4.3 billion address only in IPv6.

(255 x 255 x 255 x 255)

To make IPv4 survive this long, private addressing and NAT were created. This ended direct communications with public addressing.

To make IPv4 survive this long, _____________ and ______ were created. This ended direct communications with public addressing.

Short term solutions for the depletion of IPv4:

Long term solution for the depletion of IPV4:

NAT was meant as temporary solution and creates issues on the network as a side effect of manipulating the network headers addressing.

NAT causes latency and troubleshooting issues.

"Father of the Internet"