A comprehensive explanation of LAN switches and router devices

Switches and routers are very important devices in a networking area, where we mainly introduce network interconnection and LAN switches and router devices. The clip scheme only supports the TCP/IP protocol, but there are a variety of network layer protocols running on the existing network, such as IP, IPX, Appletalk, DECnet, Banyan, vines, etc. The key to ATM network interconnection with existing multiple LAN networks is the use of the same network layer protocol.

1. Lane emulation Fundamentals

As the name suggests, the function of Lane (emulated LAN) is to simulate a LAN on an ATM network, and the resulting LAN is called ELAN (emulated LAN, emulated LAN). The lane protocol defines the mechanism for simulating an IEEE 802.3 ethernet or IEEE 802.5 Token Ring network. The lane protocol defines the same interface to the service provided by the existing LAN to the network layer, and the data transferred in the ATM network is encapsulated in the corresponding LAN MAC packet format. The traditional LAN is simulated on ATM network, and many traditional LAN and terminal devices are interconnected through ATM networks. A new LAN is constructed on ATM networks, and the communication between these nodes is exactly the same as that of the traditional LAN. LAN simulation on the LAN hidden switch and router structure, LAN terminals do not feel the existence of ATM network, so no need to modify the hardware and software of terminal equipment, you can use the advantages of ATM network. The

Emulation protocol is implemented primarily on ATM hosts and ATM LAN bridges. ATM LAN Bridge is a converter between LAN and ATM network, and uses ALL5 protocol to fit the data of LAN. Its function is to generate ATM signaling, or to reorganize ATM signaling, to restore data frames on the LAN. The ATM host joins the LAN simulation function between the ATM adaptation layer and the high-level Protocol, so that the ATM host simulates the behavior of the traditional LAN device and communicates with the LAN. ATM Lane is set up for LAN access, and for traditional IP terminals, an ATM network is like a LAN, which contains several IP subnets that are connected by routers.

in Elan, the lane protocol defines the same business interface for the high-level as an existing LAN so that data transferred over the ATM network can still be encapsulated in the appropriate LAN MAC packet format. A solution of the lane protocol that makes all the original aspects of an ATM network, including connection building, cellular segmentation, and reassembly (SAR), fully transparent to nodes, that is, LAN nodes connected to an ATM network can have no concern over these operations in the ATM network at all. Lane enables any network higher layer protocol to run on an ATM network without modification, because the LANE protocol provides the network layer driver with the same service interface as the existing MAC protocol, such as network driveActuator Interface Specification Ndls or Open Data Link Interface ODI driver interface), do not need to make any changes to these drivers. 3lian footage the

Lane protocol provides for the operation of a single emulated LAN (ELAN), where multiple Elan can exist simultaneously on an ATM, and each ELAN simulates an Ethernet or Token Ring network. The lane protocol needs to run on the following two ATM devices (both of which are on the ATM LAN bridge mentioned above): The

ATM network on-port card (NIC)

ATM NIC (that is, the usual ATM network card) executes the lane protocol. Connect LAN terminals to an ATM network (not directly, of course), but to connect to the ATM LAN switches and routers described below that support the lane protocol, or to ATM routers that support the lane protocol. On connected terminal systems, the ATM network card provides a service interface for running LAN high-level protocols on the ATM layer. In this way, the terminal system connected to the ATM network can continue to use the original High-level network protocol to communicate, of course, connected to the ATM network, the terminal system can enjoy the advantages of the ATM network itself, such as high-bandwidth support, flexible WAN applications.

Network interconnection and LAN switches and router devices

are mainly referred to LAN-specific switches and routers that connect to ATM, to connect various LAN nodes, or to LAN terminal systems connected to ATM networks through ATM network cards that support the lane protocol. Of course, you can also directly connect an ATM host system with ATM network cards installed. LAN devices that are connected to an ATM LAN switch and router are essentially equivalent to building a bridge between an ATM network and a LAN network, and the lane protocol is equivalent to a bridging protocol that changes the MAC address of a device in a LAN network to an ATM address. So that LAN devices can still be identified after they are connected to an ATM network. The

2. Lane network makes up

Lane, which is based on client/server mode (Client/server), and a lane server is available to multiple lane clients. Lane supports multiple protocol (MULTI-PROTOCOLOVERATM,MPOA) transmissions, allowing interconnection between different lane, and supporting connectionless features and unicast, multicast, and broadcast transmissions in the LAN. Each lane customer (LEC) that supports lane is the client of the lane protocol, which is the Lane protocol server (LE) that is responsible for running the LAN High level protocol in the ATM network.