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The main task of switching is to ensure the connectivity of the nodes within a single network (see. see InfiLINK 2x2 and InfiMAN 2x2: Switching). In order to establish the communication between different networks, a new class of devices (called routers) must be used (see Figure 1). This article describes the application areas and the configuration of the Infinet devices when used as routers.
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- Switching - the process of connecting endpoint subscribers through intermediate devices. In most modern networks, frame switching is performed using the Ethernet header, based on the destination MAC address and on the vlan ID. In the example in from (Figure 1a), the data exchange between PC-1 and PC-2 is performed based on the MAC addresses. In this article, the terms switching and L2 data transmission technology are identical.
- Switch - the device that performs switching.
- Routing - the process of determining the best data transmission path between nodes belonging to different networks, according to a certain criteria. Most modern networks route packets based on the IP header (destination IP address). In the example in from (Figure 1b) the data exchange between PC-1 and PC-2 is performed based on the IP addresses. In this article, the terms routing and L3 data transmission technology are identical.
- Router - the device that performs routing.
- Local network - the network part that is in the responsibility of the an organization or enterprise. The organization's employees are responsible for assigning IP addresses to the devices in this network and an IP address conflict is very unlikely.
- Global network - the global scale network. Usually, the Internet is understood as a global network. Since many local networks are connected to the global network, the allocation of the IP addresses is performed centrally, by special organizations.
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The switch receives the frame from PC-1 and redirects it to PC-2 according to the switching table. The data transmission is performed based on the Ethernet service header, since the transmission takes place at the data link level. This mechanism is called switching.
In the scenario when where PC-1 sends data to PC-3 (Figure 1b), PC-1 fills in the frame service frame's service fields in the following way:
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Note that the IP packet header is left unchanged, while the receiver and the sender MAC addresses in the Ethernet frame header are changed. This operation was performed because the MAC addresses are used to transfer data within the same local network, i.e. when transferring data between different local networks, the MAC addresses will always be replaced. This data transfer mechanism is called routing.
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