CCNA I v5: Chapter 6 Network Layer (Routers)

What is Best Effort (IP)?

(unreliable) packet delivery is not guaranteed.

What are significant fields in the IPv4 header?

1) Version -

What are the benefits of encapsulating?

1)By doing this data layer by layer enables the services at the different layers to develop and scale without affection other layers 2)Can be readily packaged by IPv4 or IPv6 or by any new protocol

What does unreliable mean?

1)It means that IP doesn't have the capability to manage and recover from undelivered or corrupt packets. 2)It contains no information that can be processed to inform the sender whether delivery was successful. 3)No synchronization data included in the packet header for tracking the order of packet delivery. 4)No error control data to track.

What are some negative aspects of IP-best effort?

1)Packets may arrive at the destination corrupted, out of sequence, or not at all. 2)Out-of-order or missing packets

What are some negative aspects of IP-connectionless?

1)Senders are unaware whether destination devices are present and functional when sending packets. 2)Senders are unaware if destination receives the packet. 3)Senders are unaware if destination is able to access and read the packet.

What year did IPv4 become a known protocol and for whom?

1983 the Advanced Research Projects Agency Network (ARPANET)

What are four primary functions of the network layer?

Addressing end devices Encapsulation Routing De-encapsulation

What is framenting or fragmentation?

An intermediate device (router) must split up a packet when forwarding it from one medium to a medium with a smaller MTU.

IPv4 packet header fields contain _________numbers which are examined by the Layer 3 process.

Binary

What are three basic characteristics of IP?

Connectionless Best Effort Media Independent

How can an individual IP packet be communicated?

Electrically over cable, as optical signals over fiber, or wirelessly as radio signals

What are two parts of an IPv4 packet?

IP Header - Identifies the packet characteristics; Payload - Contains the Layer 4 segment information and the actual data

What is IP encapsulation?

IP packages the transport layer segment by adding an IP header.

What protocol is the Internet largely based?

IPv4

What network layer protocols are commonly implemented?

Internet Protocol version 4 (IPv4) Internet Protocol version 6 (IPv6)

What is the benefit of IP-connectionless?

It greatly reduces the overhead of IP

What is MTU?

Maximum Transmission Unit

Is transport of IP packets limited to one particular medium?

No

What is connectionless (IP)?

No connection with the destination is established before sending data packets. (Like sending a letter to someone without notifying the recipient in advance.)

What is Media Independent (IP)?

Operation independent of the medium carrying the data.

How long does the IP header remain in place for?

Remains in place until it arrives at the network layer of the destination host

What does IP rely on to ensure delivery?

TCP (for this allows IP to function very efficiently)

What protocols does the transport layer use?

TCP or UDP based on the need for reliability

What is the OSI Layer 3 also known as?

The Network Layer

How does the network layer receive the MTU value?

The data link layer passes the MTU value up to the __________ layer.

In all cases, what remains unchanged during the network layer processes?

The data portion of the packet (the encapsulated transport layer PDU)

What is one major characteristic of the media that the network layer considers?

The maximum size of the PDU that each medium can transport (MTU)

What do packets do for the network layer?

These allow the network layer to carry packets for multiple types of communication between multiple hosts.

What do network layer protocols specify?

These specify the packet structure and processing used to carry the data from one host to another host.

What does the network layer, or OSI Layer 3, do?

This layer provides services to allow end devices to exchange data across the network.

What is the role of the network layer where IP-connectionless?

To transport packets between hosts while placing as little burden on the network as possible. and That no dedicated end-to-end connection is created before data is sent.

What is IP often referred to as in terms of delivery?

Unreliable or Best-effort delivery protocol

What is the IP header used for?

Used to deliver the packet to the destination host

Can routers run protocols to operate concurrently over a network to and from the same or different hosts?

Yes