Atm
frame relay
atm and frame-relay
Network Layer This layer addresses the data. It adds an IP address which allows our data to flow across networks. The protocols involved in this layer are IP and IPX. Data Link Layer This layer provides the functional and procedural means to transfer data. It also corrects any errors that may occur in the Physical layer. The protocols used at this layer are media access control and logical link control.
The data link layer, which is the second layer of the OSI model, includes protocols such as Ethernet, Point-to-Point Protocol (PPP), and High-Level Data Link Control (HDLC). Ethernet is widely used for local area networks (LANs), while PPP is commonly used for direct connections between two network nodes. Additionally, protocols like Wi-Fi (IEEE 802.11) also operate at this layer, facilitating wireless communication. These protocols handle framing, addressing, and error detection for data transmitted over physical media.
Well-known communications protocols are Ethernet, a hardware and Link Layer standard that is ubiquitous in local area networks, and the Internet Protocol Suite, which defines a set of protocols for internetworking, i.e. for data communication between multiple networks, as well as host-to-host data transfer, and application-specific data transmission formats.
Here's what you should know: Data link layer protocols must be concerned with the rules for transmitting data across the network media, particularly with encoding and carrying "frames" of data. Although this layer includes providing error detection and notification by adding the Cyclic Redundancy Check (CRC), the Transport Layer is primarily responsible for end-to-end error-free message delivery. WAN Data-Link protocols primarily define how data frames should be packaged for different types of networks. To quote: The data link protocols available for WAN communications define how networks will carry the data frames on a given data link. The data link protocols used for WANs come in three categories: 1. Interface to IBM enterprise data centers: SDLC 2. WAN connections using peer devices: HDLC & PPP 3. Switched or relayed services: X.25/LAPB, Frame Relay, ISDN/LAPD, ATM. Some of these protocols provide functionality as high as in the Network layer of the OSI, and all of these protocols transfer data over a WAN data link.
Network Layer
DoD Four-Layer ModelThe Department of Defense Four-Layer Model was developed in the 1970s for the DARPA Internetwork Project that eventually grew into the Internet. The core Internet protocols adhere to this model, although the OSI Seven Layer Model is justly preferred for new designs. The four layers in the DoD model, from bottom to top, are:The Network Access Layer is responsible for delivering data over the particular hardware media in use. Different protocols are selected from this layer, depending on the type of physical network.The Internet Layer is responsible for delivering data across a series of different physical networks that interconnect a source and destination machine. Routing protocols are most closely associated with this layer, as is the IP Protocol, the Internet's fundamental protocol.The Host-to-Host Layer handles connection rendezvous, flow control, retransmission of lost data, and other generic data flow management. The mutually exclusive TCP and UDP protocols are this layer's most important members.The Process Layer contains protocols that implement user-level functions, such as mail delivery, file transfer and remote login.
TELNET
The IP stack, also known as the Internet Protocol Suite, is a set of networking protocols that govern how data is transmitted over the internet. It is commonly organized into four layers: the application layer, transport layer, internet layer, and link layer. Each layer has its own specific functions and protocols, such as TCP and UDP at the transport layer and IP at the internet layer, enabling communication between devices across diverse networks. This layered architecture helps manage the complexities of data transmission and ensures interoperability among various network technologies.
An OSI Layer 3 protocol is primarily responsible for the routing and forwarding of data packets across networks. The most well-known Layer 3 protocol is the Internet Protocol (IP), which facilitates communication between devices on different networks by providing logical addressing. Other Layer 3 protocols include Internet Control Message Protocol (ICMP) and Address Resolution Protocol (ARP), which support various network functions and error reporting. These protocols ensure that data can be effectively directed and managed across complex network infrastructures.
physical layer.
The network layer is designated as Layer 3 in the OSI (Open Systems Interconnection) model. It is responsible for routing data packets between devices across different networks, handling logical addressing, and determining the best path for data transmission. Protocols commonly associated with this layer include Internet Protocol (IP) and Internet Control Message Protocol (ICMP).