From ab6176cef833691ec81f5ec45567ef94c366febc Mon Sep 17 00:00:00 2001 From: Nick Leeman Date: Wed, 3 Nov 2021 21:31:46 +0100 Subject: [PATCH] Vault sync: 2021-11-03 21:31:46 --- .obsidian/workspace | 22 +++---- School/Analyse/Layers/1. Physical Layer.md | 6 ++ School/Analyse/Layers/2. Datalink Layer.md | 6 ++ School/Analyse/Layers/3. Network Layer.md | 6 ++ School/Analyse/Layers/4. Transport Layer.md | 10 +++ School/Analyse/Layers/Application Layer.md | 15 ++++- School/Analyse/Layers/Presentation Layer.md | 13 ++++ School/Analyse/Layers/Session Layer.md | 10 +++ School/Analyse/Layers/Untitled.md | 0 School/Analyse/OSI Model.md | 71 --------------------- 10 files changed, 76 insertions(+), 83 deletions(-) create mode 100644 School/Analyse/Layers/1. Physical Layer.md create mode 100644 School/Analyse/Layers/2. Datalink Layer.md create mode 100644 School/Analyse/Layers/3. Network Layer.md create mode 100644 School/Analyse/Layers/4. Transport Layer.md create mode 100644 School/Analyse/Layers/Presentation Layer.md create mode 100644 School/Analyse/Layers/Session Layer.md delete mode 100644 School/Analyse/Layers/Untitled.md diff --git a/.obsidian/workspace b/.obsidian/workspace index 0e7ca93..3af1735 100644 --- a/.obsidian/workspace +++ b/.obsidian/workspace @@ -9,7 +9,7 @@ "state": { "type": "markdown", "state": { - "file": "School/Analyse/OSI Model.md", + "file": "School/Analyse/Layers/Application Layer.md", "mode": "source" } } @@ -68,7 +68,7 @@ "state": { "type": "backlink", "state": { - "file": "School/Analyse/OSI Model.md", + "file": "School/Analyse/Layers/Application Layer.md", "collapseAll": false, "extraContext": false, "sortOrder": "alphabetical", @@ -87,15 +87,15 @@ }, "active": "bc6e8ad9aa0f44c3", "lastOpenFiles": [ - "School/Analyse/OSI Model.md", - "School/Analyse/Layers/Untitled.md", "School/Analyse/Layers/Application Layer.md", - "School/Analyse/Network Types.md", - "School/Development/Foreign Key.md", - "School/Development/Primary Key.md", - "School/Development/SQL Database.md", - "School/Analyse/Images/OSI-model.png", - "School/Analyse/Network Software.md", - "School/Analyse/Computer Networks.md" + "School/Analyse/Layers/4. Transport Layer.md", + "School/Analyse/Layers/1. Physical Layer.md", + "School/Analyse/Layers/3. Network Layer.md", + "School/Analyse/Layers/2. Datalink Layer.md", + "School/Analyse/Layers/Presentation Layer.md", + "School/Analyse/OSI Model.md", + "School/Analyse/Comminucation Mediums.md", + "School/Analyse/Computer Networks.md", + "School/Analyse/Network Software.md" ] } \ No newline at end of file diff --git a/School/Analyse/Layers/1. Physical Layer.md b/School/Analyse/Layers/1. Physical Layer.md new file mode 100644 index 0000000..4e342ae --- /dev/null +++ b/School/Analyse/Layers/1. Physical Layer.md @@ -0,0 +1,6 @@ +# 1. Physical Layer +This layer is responsible for the actual physical transfer of data between devices via cables or other mediums using switches, routers, etc.. + +This layer also converts the data into a bit-stream of 1's and 0's. + +The signal convention must be the same on both devices. (Meaning of a 0 and a 1) \ No newline at end of file diff --git a/School/Analyse/Layers/2. Datalink Layer.md b/School/Analyse/Layers/2. Datalink Layer.md new file mode 100644 index 0000000..045da6d --- /dev/null +++ b/School/Analyse/Layers/2. Datalink Layer.md @@ -0,0 +1,6 @@ +# 2. Datalink Layer +The Data Link Layer is responsible for handling the data transfer between two devices on the **same** network. (so a bit like the Network Layer) + +The Data Link Layer also splits up packets into smaller chunks called a frame. The reverse happens on the receiving device (reassembling frames into packets). + +Like the Network Layer the Data Link Layer is also responsible for flow control and error checking. However it only does this for inter-network communications. (Local network) \ No newline at end of file diff --git a/School/Analyse/Layers/3. Network Layer.md b/School/Analyse/Layers/3. Network Layer.md new file mode 100644 index 0000000..a5f5caa --- /dev/null +++ b/School/Analyse/Layers/3. Network Layer.md @@ -0,0 +1,6 @@ +# 3. Network Layer +The Network Layer is responsible for handling the data transfer between two different networks. This means that this layer is not needed if the receiving device is on the same network. + +The Network Layer breaks up segments from the Transport layer into smaller chunks called [[Packets]]. The reverse happens on the receiving device (reassembling packets into segments). + +Furthermore the Network Layer also finds the optimal path to travel from origin network to the destination network. This is called routing. \ No newline at end of file diff --git a/School/Analyse/Layers/4. Transport Layer.md b/School/Analyse/Layers/4. Transport Layer.md new file mode 100644 index 0000000..462c185 --- /dev/null +++ b/School/Analyse/Layers/4. Transport Layer.md @@ -0,0 +1,10 @@ + # 4. Transport Layer +The Transport Layer is responsible for the end-to-end communication between 2 devices. + +The Transport layer on the sending device takes data from the Session Layer and breaks them up in chunks called segments. + +On the receiving device the Transport Layer reassembles the segments of data that the Session Layer can consume. + +While sending data via a network data can get corrupted, the Transport layer also ensures the data being received is complete and correct, and requesting a retransmission if its not. + +The Transport Layer also controls the flow of outgoing data so that the receiver is not overwhelmed with data. (fast to slower connections for example) diff --git a/School/Analyse/Layers/Application Layer.md b/School/Analyse/Layers/Application Layer.md index 68a62c2..6a94bbc 100644 --- a/School/Analyse/Layers/Application Layer.md +++ b/School/Analyse/Layers/Application Layer.md @@ -1 +1,14 @@ -# Application Layer \ No newline at end of file +# Application Layer +The application Layer provides services to the end user. So this is the layer the user actually interacts with. + +These services are usually protocols that interact with the data that the user uses. + +**Examples of services (protocols):** +- HTTP +- FTP +- IRC +- SSH +- DNS +- SMTP + +For example a web browser like Google Chrome uses the HTTP protocol to browse files on the internet. And the mail client Outlook uses the SMTP protocol to send mail via the internet. \ No newline at end of file diff --git a/School/Analyse/Layers/Presentation Layer.md b/School/Analyse/Layers/Presentation Layer.md new file mode 100644 index 0000000..6a23b3c --- /dev/null +++ b/School/Analyse/Layers/Presentation Layer.md @@ -0,0 +1,13 @@ +# Presentation Layer +The presentation layer is responsible for preparing the data so that it can be used by the Application Layer. + +**Presentation layer is responsible for:** +- Translation of data +- Encryption of data +- Compression of data + +For example, two devices can use different types of encoding on their data, the presentation layer will translate the data in a way that the Application Layer can understand. + +When sending sensitive data, we would like to encrypt the data so that its secure. The Presentation layer is responsible for encrypting and decrypting ingoing or outgoing data. + +Also when sending of receiving data we sometimes want to compress the data so that sending and receiving data is more efficient. (smaller size) \ No newline at end of file diff --git a/School/Analyse/Layers/Session Layer.md b/School/Analyse/Layers/Session Layer.md new file mode 100644 index 0000000..6a9ca9b --- /dev/null +++ b/School/Analyse/Layers/Session Layer.md @@ -0,0 +1,10 @@ +# Session Layer +The session layer is responsible for opening and closing connections between two devices. The duration of a connection is called the session. + +The session layer ensures that the connections remains active and open so that the data being received and/or send is complete. + +For example when sending a big file to someone, which takes some time, the session layer will keep the connection open long enough to send the complete file. + +The session layer also synchronizes the data transfer with checkpoints. For example, if a 50 MB file is send to a device, the session layer could set a checkpoint every 10 MB. In case of a disconnect (session close), the session could be restored to a certain checkpoint and the data transfer can resume where it disconnected. + +This way we do not need to completely resend the file. diff --git a/School/Analyse/Layers/Untitled.md b/School/Analyse/Layers/Untitled.md deleted file mode 100644 index e69de29..0000000 diff --git a/School/Analyse/OSI Model.md b/School/Analyse/OSI Model.md index d05751f..54d45ee 100644 --- a/School/Analyse/OSI Model.md +++ b/School/Analyse/OSI Model.md @@ -11,74 +11,3 @@ As you can see the model has 7 layers. Each layer has their own responsibility. **Note: We don't actually "use" the OSI model, we mostly use the [[TCP/IP Model]] now. The implementation is exactly the same, only some layers are different.** -## 7. [[ Application Layer ]] -The application Layer provides services to the end user. So this is the layer the user actually interacts with. - -These services are usually protocols that interact with the data that the user uses. - -**Examples of services (protocols):** -- HTTP -- FTP -- IRC -- SSH -- DNS -- SMTP - -For example a web browser like Google Chrome uses the HTTP protocol to browse files on the internet. And the mail client Outlook uses the SMTP protocol to send mail via the internet. - -## 6. Presentation Layer -The presentation layer is responsible for preparing the data so that it can be used by the Application Layer. - -**Presentation layer is responsible for:** -- Translation of data -- Encryption of data -- Compression of data - -For example, two devices can use different types of encoding on their data, the presentation layer will translate the data in a way that the Application Layer can understand. - -When sending sensitive data, we would like to encrypt the data so that its secure. The Presentation layer is responsible for encrypting and decrypting ingoing or outgoing data. - -Also when sending of receiving data we sometimes want to compress the data so that sending and receiving data is more efficient. (smaller size) - -## 5. Session Layer -The session layer is responsible for opening and closing connections between two devices. The duration of a connection is called the session. - -The session layer ensures that the connections remains active and open so that the data being received and/or send is complete. - -For example when sending a big file to someone, which takes some time, the session layer will keep the connection open long enough to send the complete file. - -The session layer also synchronizes the data transfer with checkpoints. For example, if a 50 MB file is send to a device, the session layer could set a checkpoint every 10 MB. In case of a disconnect (session close), the session could be restored to a certain checkpoint and the data transfer can resume where it disconnected. - -This way we do not need to completely resend the file. - -## 4. Transport Layer -The Transport Layer is responsible for the end-to-end communication between 2 devices. - -The Transport layer on the sending device takes data from the Session Layer and breaks them up in chunks called segments. - -On the receiving device the Transport Layer reassembles the segments of data that the Session Layer can consume. - -While sending data via a network data can get corrupted, the Transport layer also ensures the data being received is complete and correct, and requesting a retransmission if its not. - -The Transport Layer also controls the flow of outgoing data so that the receiver is not overwhelmed with data. (fast to slower connections for example) - -## 3. Network Layer -The Network Layer is responsible for handling the data transfer between two different networks. This means that this layer is not needed if the receiving device is on the same network. - -The Network Layer breaks up segments from the Transport layer into smaller chunks called [[Packets]]. The reverse happens on the receiving device (reassembling packets into segments). - -Furthermore the Network Layer also finds the optimal path to travel from origin network to the destination network. This is called routing. - -## 2. Data Link Layer -The Data Link Layer is responsible for handling the data transfer between two devices on the **same** network. (so a bit like the Network Layer) - -The Data Link Layer also splits up packets into smaller chunks called a frame. The reverse happens on the receiving device (reassembling frames into packets). - -Like the Network Layer the Data Link Layer is also responsible for flow control and error checking. However it only does this for inter-network communications. (Local network) - -## 1. Physical Layer -This layer is responsible for the actual physical transfer of data between devices via cables or other mediums using switches, routers, etc.. - -This layer also converts the data into a bit-stream of 1's and 0's. - -The signal convention must be the same on both devices. (Meaning of a 0 and a 1) \ No newline at end of file