At which layer does switching occur in the Cisco modified TCP/IP model?
- Data Link
Switches make switching decisions based on MAC addresses. Because MAC address reside in the Data Link layer of the TCP/IP or DoD model, this is the layer where switching occurs. A switch is a high-speed networking device that receives incoming data packets from one of its ports and directs them to a destination port for local area network access. A switch will redirect traffic bound outside the local area to a router for forward through an appropriate WAN interface.
The modified TCP/IP model is a model by Cisco that departs from the DoD model by breaking the bottom layer, the Link layer, into two layers called the Data Link and the Physical layer.
Other versions of the model refer to the Link as the Network Interface layer.
The layers in ascending order are:
Switches do not operate on the Internet layer. Routers are an example of devices that operate on this layer, which is where IP addresses are located. A router is a device that examines the contents of data packets transmitted within or across networks. Routers determine if a source and destination are on the same network, or whether data mist be transferred from one network to another, either between locally available network segments, or across a wide-area link to access other, more distant networks.
Switches do not operate on the Transport layer. This is the layer where port numbers are added to the packet.
Switches do not operate on the Physical layer. This is the layer where the information is transmitted as ones and zeros using the underlying technology of the medium.
The Application layer of the TCP/IP model corresponds to the Application, Presentation, and Session layers of the OSI model.
The Transport layer of the TCP/IP model correspond to the Transport layer of the OSI model.
The Internet layer of the TCP/IP model correspond to the Network layer of the OSI model. Internet protocol (IP), address resolution protocol (ARP), and Internet control message protocol (ICMP) operate at the Internet layer.
The Link layer of the TCP/IP model corresponds to the Data Link and Physical layers of the OSI model.
Objective: Network Concepts
Sub-Objective: Describe the function of the network models