CCNA Completo | Leccion 2 | Stack TCP/IP y Modelo OSI
Introduction to TCP/IP and OSI Models
Overview of Protocol Stacks
- The video introduces the topic of protocol stacks, specifically focusing on TCP/IP and the OSI model as part of a comprehensive CCNA course.
- TCP/IP is highlighted as one of the most common and relevant protocol stacks in use today, consisting of four layers: application, transport, internet, and network access.
Understanding Reference Models
- A reference model provides tools for understanding and implementing relationships between protocols; it also offers a language for describing network functions.
- The OSI model consists of seven layers: application (layer 7), presentation (layer 6), session (layer 5), transport (layer 4), network (layer 3), data link (layer 2), and physical (layer 1).
Comparing OSI Model with TCP/IP
Layer Functions
- In the OSI model, the application layer and network access layer from TCP/IP are divided into more specific layers to describe their functions better.
- The original TCP/IP model focuses on four layers that emphasize applications needing to send/receive data versus lower layers focused on transmitting bits.
Hybrid Model Usage
- A hybrid model combining application and transport layers from TCP/IP with data link and physical layers from OSI is proposed for current networking operations.
Data Communication Challenges
Issues with Large Data Flows
- Sending large continuous streams of data can create problems for other devices sharing the same communication channel, potentially causing delays or complete message loss during transmission.
Segmentation Process
- Segmenting data into smaller manageable pieces before transmission is recommended to avoid issues associated with large flows. This process enhances efficiency in communication.
Encapsulation and Decapsulation
Encapsulation Explained
- Data must traverse through the protocol stack starting from the top layer; each layer adds its own header (and sometimes a trailer). This process is known as encapsulation.
Protocol Data Units (PDUs)
- Different PDUs are defined based on their respective layers:
- Application Layer: Data
- Transport Layer: Segments (TCP)/Datagrams (UDP)
- Network Layer: Packets
- Data Link Layer: Frames
- Physical Layer: Bits
Decapsulation Process