Chapter 3 network layerinternet protocols 63 figure 3. To this end, the iec 624393 parallel redundancy protocol prp provides seamless recovery in layer 2 networks by delegating the redundancy management to the endnodes. Layer 2 networking ethernet switching user guide juniper. Layer 2 protocols are designed to be plugandplay, and forward traffic without configuration.
Arpand rarpoperate underneath ip but above the link layer so. Internet protocol ip and internet packet exchange ipx are examples of network layer protocols. Layer 2, also known as the data link layer, is the second level in the seven layer osi reference model for network protocol design. To understand layer 2 network protocols, we must learn about the open systems interconnection osi model and layer 2 first. Routing protocols general terms algorithms, design, performance, management, reliability keywords data center network fabric, layer 2 routing in data centers 1. Introduction there is an increasing trend toward migrating applica. Traditional internet routers operate at the network layer by. Internet protocol version 4 ipv4 internet protocol version 6 ipv6 note. Tcpip also defines how to interface the network layer with the data link and physical layers, but is not directly concerned with these two layers themselves. Conceptual data flow in a simple network topology of two hosts a.
The layer 2 protocol, such as ethernet, will also include a reference to which layer 3 protocol has been used and a checksum to ensure data integrity. Icmpand igmprun over ip may be considered part of the network layer. At a high level, the layer 2 leaf spine l2ls is a 2 tier topology comprised of spine and leaf switches. Network models are organized into layers, with each layer representing a specific networking function. Pdf availability improvement of layer 2 seamless networks. In figure 2 3, an end system transmits data packets to a receiving end system traversing two differ. Tcp and udp application transport network data link physical. The common protocols at this layer are ip which is paired with tcp at the transport layer for internet network and ipx which is paired with spx at the transport layer for some older macintosh, linus, unix, novell and windows networks. Explain why the ipv4 protocol requires other layers to provide reliability. Layer 2 network access protocols user guide published 20210317. Exchange ipx are examples of network layer protocols. Each of the devices on the network can be thought of as a node. For our example, the layer 2 information might look something like. Technologies at layer 2 or medium access control layer are ethernet, atm, fddi, cell relay and frame relay.
A datalink protocol specifies the structure of the. This stack configuration is typical in conventional. Layer 2 is primarily used for highspeedhighdata throughput pointtopoint applications between telecommunication facilities. Null components same interfaces trans control prot novell netware ipx. The data link layer provides the functional and procedural means to transfer data between network entities and might provide the means to detect and possibly correct errors. However, redundant paths in a switched ethernet network can cause both physical and logical layer 2 loops. The ubiquity of carrierprovided layer 2 wan networks makes it a.
Tutorial on network layers 2 and 3 radia perlman intel labs. The ohio state university raj jain 2 9 layering protocols of a layer perform a similar set of functions all alternatives for a row have the same interfaces choice of protocols at a layer is independent of those of at other layers. Ethernet, fddi and other layer medium technologies are also known as local area network technologies. Network layer in communications network layer protocols there are several network layer protocols in existence. Figure 1 illustrates the protocols that may provide transport for ethernet services and their corresponding control planes. They may be tunneled using techniques at layers 1, 2 or 3. Redundant networks require adding physical paths, but logical redundancy must also be part of the design. Chapter 1 preface this is the current draft of the second edition of the computer networking. Udp is the basic transport layer protocol, providing an. Introductiona network can be defined as a group of computers and other devices connected in some ways so as to be able to exchange data. Network protocols acronyms and abbreviations list of network protocols with abbreviations order by index. Layer 2 protocols types of layer 2 protocols manageengine. How the different l2cp destination mac addresses and protocol types should be handled according to metro ethernet forum for epl option 1 and 2, etree, elan, evpl, evplan and evptree. When source and destination are in different networks, the network layer ip must deal with these differences.
Mapping between ip addresses and network physical addresses. Roles, functions and protocols as layer six of the osi model, the presentation layer is primarily responsible for managing two networking characteristics. The spanning tree protocol link between the switches is also mapped. The protocols are developed in increasing complexity to help. The physical layer consists of the basic networking hardware technologies which transmit data, moving it across the network. The ubiquity of carrierprovided layer 2 wan networks makes it a required consideration for an organization building a wan. The internet protocols primary function is logical network layer addressing of. Almost all link layer protocols encapsulate each network layer datagram within a network layer datagram is inserted, and a number of header fields. Application layer functionality and protocolslayer 7. At a high level, the layer 2 leaf spine l2ls is a 2. Data link layer, layer 2 in the tcpipbased layered network, layer 2 is the data link layer. Advanced computer networks data link layer 6 host a host b layer 4 node 2 node 1 layer 4 layer 2 frame tanenbaums data link layer model assume the sending host has infinite supply of messages.
A node constructs a framefrom a single packetmessage. Version ihl type of service total length identification flags fragment offset ttl protocol header checksum source address destination address options padding figure 3. Network layerinternet protocols ip higher education. Network layer protocols 2015 jens andersson etsf05etsf10 internet protocols. Enterprise network aggregation access layer 3 links layer 2 trunks hierarchical design network layers. The actual protocols encompassed in the link layer are numerous, and the implementation details can be found in various documents throughout the internet and in trade texts. A network can be defined as a group of computers and other. Network layer provides the same functionality as the physical, the data link and network layers in the osi model. Lan layer 2 qoscos protocol for traffic prioritization205. Basically, spanning tree protocol, the software behind it, helps network devices and end hosts to detect the actual lan topology, so to understand what the layout. When it comes to networking, layer 2 can be a very weak link.
The network layer must know the topology of the subnet and choose appropriate paths through it. Icmpv4 helps ipv4 to handle some errors that may occur in delivery. Layer 2 wan services provide highperformance, costeffective, and reliable services within metropolitan areas and, in some cases, for broader geographic areas. Metro ethernet forum layer 2 control protocol handling. Physical layer 2 network 2 figure 2 3 protocol stacks in a network with heterogeneous links. Touted as the data link layer, layer 2 is the second of the sevenlevel osi model that is.
Layer 2 defines how to communicate between devices on the same network. Protocols on one layer will interact with protocols on the layer above and below it, forming a protocol suite or stack. The layer 2 leaf and spine l2ls topology is the foundation of aristas universal cloud network architecture. Yet to run on a computer or other end device, email requires several applications and services. Email services and smtppop protocols email, the most popular network service. A laymans guide to layer 1 switching arista networks. Anything designed by a committee whose charter is to design a layer n protocol. Data center core routed layer which is distinct from enterprise network core provides scalability to build multiple. Traditional internet routers operate at the network layer by examining layer. Types of network protocols and their uses in this chapter, you can find a detailed description of various useful protocols and their types. Course for udemy introduction to computer networks. Introduction to networking protocols and architecture.
Ip and the internet architecture 3 network layer link layer ip arp network access media icmp igmp. Understanding data link layer encapsulation ccna hub. To understand layer 2 network protocols, we must learn about the. Possible services that can be offered by a link layer protocol include. Also, you will learn about the most common types of protocols used by the network models while communicating one system with another. While a protocol that affects the configuration or operation of a layer 2 network can use any type of frame with ordinary unicast or multicast addresses, the protocols that are considered layer 2 control protocols with the reserved addresses above can take advantage of special. Gaining popularity is ipv6 due to increased addressing space and security handling. Data center core routed layer which is distinct from enterprise network core provides scalability to build multiple aggregation blocks aggregation layer provides the boundary between layer 3 routing and layer 2 switching. Two example application layer protocols are post office protocol pop and simple mail transfer protocol smtp. Because of the growth in internetbased networks, iptcp are becoming the leading protocols for most networks. Introduction the layer 2 control plane is separated into multiple customer and provider control planes. Pdf effect of routing protocols and layer 2 mediums on.
The data link layer, or layer 2, is the second layer of the seven layer osi model of computer networking. Any computer network internetwork is designed based on the osi standards. The lowest layer of the internal functions of a communication system is known as layer 1, the physical layer. Lecture 7 network layer 2 chapter 5 sehs3321 l7 1 outline \u0001 routing protocols link state. The network layer typically provides information about which transport layer protocol is being used, as well as local checksums to ensure data integrity. Layer 2 protocols 1 29 layer 2 protocols 1 ethernet broadcast network equal access csmacd carrier sense multiple access collision detection token ring one node transmits, all receive broadcast each node transmits in turn failure in a node affects the entire ring 029 ethernet we use almost. Protocol encapsulation chart a pdf file illustrating the relationship between common protocols and the osi reference model. Legacy network layer protocols are not discussed in this course. Network layer and ip protocol cse 32, winter 2010 instructor. These functions are controlled by protocols, which are rules that govern endtoend communication between devices.
Logical layer 2 loops can occur because of the natural operation of switches, specif. Encryption at this level encapsulates any layer 2 protocol crossing the link, unlike layer 3 where only ip packets are encrypted. If you arent using ethernet as your l2 protocol, some. Ssi, 2006 cse 123a lecture 2 protocols and layering21 the osi layering model application presentation session transport network datalink physical end host application presentation session transport network datalink physical end host network datalink physical network node network datalink physical network node top 4 layers are endtoend. Layer 2 protocols are a list of communication protocols used by layer 2 devices such as network interface cards nic, switches, multiport bridges, etc. Data packets traversed from network layer handed over to data link layer which is responsible for framing of data packets received from network layer.
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