3. TCP/IP & OSI

http data sent from YT web server displayed via web browser. what's this an example of?

same layer interaction

http data has been encapsulated with three separate headers and one trailer. what's the name of this PDU?

frame

Packet

OSI layer 3 PDU. two headers (layer 3 and 4) and no trailer

segment

OSI layer 4 PDU. one header (layer 4) and no trailer

data

upper layer data prior to encapsulation. no headers or trailer

which layers of network model most most relevant to role of network engineer?

transport - network - data link - physical

link layer of TCP/IP model is equivalent to what layer(s) of OSI model?

data link - physical

Which layer of OSI model provides host-to-host communications?

transport

networking models

categorize and give a structure for networking protocols and standards

network protocol

set of rules defining how network devices and sw should work

OSI

open systems interconnection [model].

name the seven layers of the osi model

7. Application

6. Presentation

5. Session

4. Transport

3. Network

2. Data Link

1. Physical

what network model was made by the international organization for standardization (iso)

osi model

application layer

layer closest to the end user. interacts with sw apps (eg web browser)

name 2 layer seven protocols

http and https

what are the functions of layer 7

identifying common partners. synchronizing communication.

encapsulation

as data processed through osi stack each layer adds something to origional data

de-encapsulation

additonal info removed as data is processedup the stack of network model from physical layer up to app layer

adjecent layer interaction

both encap and de-encap are examples of this. interaction bw dif layers of osi model.

same-layer interaction

interaction bw osi model layers which allows for same layers to interact with each other

presentation layer

data in app layer is in 'application format'. it needs to be 'translated' into dif format to be sent over network.

what are the functions of layer 6

translate bw app and network formats. translate bw dif app layer formats.

session layer

controls dialogues (sessions) bw communicationg hosts

what are the functions of layer 5

establishes, manages, and terminates connections bw local app and the remote app (eg bw your web browser and YT)

transport layer

segments and reassembles data for communications between end hosts. breaks large pieces of data into smaller segments which can be more easily sent over network and are less likely to cause transmission probs if errors happen. provide host to host communication (aka end to end communication).

network layer

provides connectivity between end hosts on dif networks (ie outside the LAN). provides logical addressing (IP addresses). provides path selection bw source and destination. routers operate at this layer.

data link layer

provides note to node connectivity and data transfer (eg pc to switch, switch to router, router to router). defines how data is formatted for the transmission over a phys medium (eg copper utp cables). detects and (possibly) corrects phys layer errors. uses layer 2 addressing, separate from layer 3 addressing. switches operate at this layer.

physical layer

defines phys characteristics of medium used to transfer data bw devices. digital bits converted into electrical (for wired connections) or radio (for wireless connections) signals.

acronym for osi model

Please Do Not Teach Students Pointless Acronyms

Physical, Data Link, Network, Transport, Session, Presentation, Application

segment

when layer 4 header is added at the transport layer, this is the combination of data plus layer 4 header

packet

layer 3 header added on at network layer (that includes IP address)

frame

complete unit where layer 2 header and trailer are added at the data link layer

PDU

protocol data unit. include data, segment, packet, and frame.

tcp/ip suite

conceptual model and set of communications protocols used in the internet and other networks.

tcp/ip suite

developed by US Dept of Defence through DARPA (defense advanced research projects agency)

tcp/ip suite equivalent to osi model application, presentation, and session layers

application layer

tcp/ip suite equivalent to osi model transport layer

transport layer

tcp/ip suite equivalent to network layer

internet layer

tcp/ip suite equivalent to data link layer and physical layer

link layer

tcp/ip suite layers

1. link layer, 2. internet layer, 3. transport layer, 4. application layer