[CCNA] CCNA1 - Chapter3

네트워크/CCNA

happyso 2022. 10. 5. 23:49

Flow control allows for this by ensuring that data is not sent too fast for it to be received properly.

Encapsulation is the process of placing one message format into another message format.
An example is how a packet is placed in its entirety into the data field as it is encapsulated into a frame.

Network protocols are implemented in hardware, or software, or both.
Network protocols are required to exchange information between source and destination devices in both local and remote networks.
They interact with each other within different layers of a protocol stack.

The TCP/IP internet layer provides the same function as the OSI network layer.
The transport layer of both the TCP/IP and OSI models provides the same function.
The TCP/IP application layer includes the same functions as OSI Layers 5, 6, and 7.
The TCP/IP model consists of four layers: application, transport, internet, and network access.
The OSI model consists of seven layers: application, presentation, session, transport, network, data link, and physical.
The top three layers of the OSI model: application, presentation, and session map to the application layer of the TCP/IP model.

Logical addresses, also known as IP addresses, are encapsulated at the network layer.
Physical addresses are encapsulated at the data link layer.
Port addresses are encapsulated at the transport layer. No addresses are encapsulated at the physical layer.

DNS, DHCP, and FTP are all application layer protocols in the TCP/IP protocol suite.
ARP and PPP are network access layer protocols, and NAT is an internet layer protocol in the TCP/IP protocol suite.

Proprietary protocols have their definition and operation controlled by one company or vendor.
Some of them can be used by different organizations with permission from the owner.
The TCP/IP protocol suite is an open standard, not a proprietary protocol.

When received at the physical layer of a host, the bits are formatted into a frame at the data link layer.
A packet is the PDU at the network layer.
A segment is the PDU at the transport layer.
A file is a data structure that may be used at the application layer.

At the transport layer, a host computer will de-encapsulate a segment to reassemble data to an acceptable format by the application layer protocol of the TCP/IP model.

In order to send data to ServerB, HostA will generate a packet that contains the IP address of the destination device on the remote network and a frame that contains the MAC address of the default gateway device on the local network.

ISOC - The organization promotes the open development, evolution, and use of the internet throughout the world
ISO - This organization is the largest developer of international standars in the world for a wide variety of products and services. It is know for its Open System Interconection (OSI) reference model.
IANA - This organization is responsible for overseeing and managing IP address allocation, domain name management, and protocol identifiers
EIA - international standards and trade organization for electronics organizations. It is best known for its standards related to electrical wiring, connectors, and the 19-inch racks used to mount networking equipment.

application protocol - governing the way a web server and a web client interact
internet protocol - taking the segments from transport protocol, encapsulating them into packets, and assigning them with appropriate addresses
network access protocol - preparing packets to be transmitted over the network media
transport protocol - managing the individual conversations between web servers and web clients