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--- method_7_notes [2022/09/24 19:17] – created gman
+++ method_7_notes [2023/01/12 00:49] (current) – gman
@@ Line 1: / Line 1: @@
-====== NOTES ON METHODOLOGY ======
+====== Basic Networking ======
 ===== OSI Model =====
@@ Line 5: / Line 5: @@
 A conceptual model of networking based on seven "layers":
-^  Layer  ^  Description  ^
+^ **#** ^  Layer  ^  Description  ^
-| 7. Application | Provides networking options (an interface to transmit data) to programs running on the computer. |
+| 7 | **Application** | Provides networking options (an interface to transmit data) to programs running on the computer. |
+| 6 | **Presentation** | Translates the data into a standardized format (so the receiving machine can read it); it also handles encryption, compression, or other transformations of the data.|
+| 5 | **Session** | Sets up and maintains a connection with the other computer across the network (connection is unique to this communication). |
+| 4 | **Transport** | Decides on a transport protocol (TCP or UDP) and then divides up the data to be sent over the network (TCP: segments; UDP: datagrams). |
+| 3 | **Network** | [router level] Locates the destination computer via logical addressing (i.e., IP Addresses). |
+| 2 | **Data Link** | [switch level] Identifies the MAC/hardware addresses of the machines on the network (mapping each IP Address to the device's MAC/hardware address). Runs a CRC for data integrity and then presents the data in a suitable format for transmission.|
+| 1 | **Physical** | The hardware that communicates with electrical impules (1's and 0's) or light (on and off).|
-**6. Presentation:** Translates the data into a standardized format (so the receiving machine can read it); it also handles encryption, compression, or other transformations of the data.
+The machine that receives the transmssion does so on Layer 1, then passes the data up the stack to Layer 2, etc.
-**5. Session:** Sets up and maintains a connection with the other computer across the network (connection is unique to this communication).
+===== TCP/IP Model =====
-**4. Transport:** Decides on a transport protocol (TCP or UDP) and then divides up the data to be sent over the network (TCP: segments; UDP: datagrams).
+^ **#** ^  Layer  ^  Description  ^
+| 4 | **Application** | Provides applications with standardized data exchange via protocols like HTTP, FTP, POP3, SMTP, and SNMP. The payload is the actual application data. |
+| 3 | **Transport** | Responsible for maintaining end-to-end communications across the network via TCP and UDP protocols. |
+| 2 | **Internet** | Deals with packets and connects independent networks to transport the packets across network boundaries via protocols like ICMP. |
+| 1 | **Network Access** | The "physical" or "link" layer; defines the networking methods within the scope of the local network link on which hosts communicate without intervening routers. Protocol: Ethernet. |
-. Network: [router level] Locates the destination computer via logical addressing (i.e., IP Addresses).
+===== OSI & TCP/IP =====
-. Data Link: [switch level] Identifies the MAC/hardware addresses of the machines on the network (mapping each IP Address to the device's MAC/hardware address). Runs a CRC for data integrity and then presents the data in a suitable format for transmission.
+^ OSI MODEL ^ TCP/IP MODEL ^
+| 7. Application  | 4. Application       |
-. Physical: The hardware that communicates with electrical impules (1's and 0's) or light (on and off).
+| 6. Presentation | :::                  |
+| 5. Session      | :::                  |
-The machine that receives the transmssion does so on Layer 1, then passes the data up the stack to Layer 2, etc.
+| 4. Transport    | 3. Transport         |
+| 3. Network      | 2. Internet          |
+| 2. Data Link    | 1. Network Interface |
+| 1. Physical     | :::                  |
+  * The TCP/IP model was introduced first (in 1982 by the US DoD) and is the standard upon which modern networking is based.
+  * The OSI model was developed later as a more comprehensive guide for learning.