Matching an IP packet’s destination IP address to the IP routing table (routers, Layer 3 switches)Įncrypting the data and adding a new IP header (for virtual private network processing)Ĭhanging the source or destination IP address (for Network Address Translation processing)ĭiscarding a message due to a filter (access control lists, port security)Īll the items in the list make up the data plane, because the data plane includes all actions done per message. Matching an Ethernet frame’s destination Media Access Control (MAC) address to the MAC address table (Layer 2 switches) Routers R3 and R4 also receive, process, and forward the packet (steps 3 and 4).ĭe-encapsulating and re-encapsulating a packet in a data-link frame (routers, Layer 3 switches)Īdding or removing an 802.1Q trunking header (routers and switches) R1 does some processing on the received packet, makes a forwarding (routing) decision, and forwards the packet (step 2). If you focus on the Layer 3 logic for a moment, the host sends the packet (step 1) to its default router, R1. In other words, anything to do with receiving data, processing it, and forwarding that same data-whether you call the data a frame, a packet, or, more generically, a message-is part of the data plane.įor example, think about how routers forward IP packets, as shown in Figure 16-1. The term data plane refers to the tasks that a networking device does to forward a message. This section takes those familiar facts about how networking devices work and describes the three planes most often used to describe how network programmability works: the data plane, the control plane, and the management plane. They use many different protocols to learn useful information such as routing protocols for learning network layer routes.Įverything that networking devices do can be categorized as being in a particular plane. They forward messages: switches forward Ethernet frames, and routers forward packets. For instance, routers and switches physically connect to each other with cables, and with wireless, to create networks. What does a router do? What does a switch do? Stop and think about what networking devices do. Then this section explains how some centralized controller software, called a controller, creates an architecture for easier programmatic control of a network. It starts by breaking down some of the components of what exists in traditional networking devices. This first major section explains the most central concepts of SDN and network programmability. At the end of that rearrangement, the devices in the network still forward messages, but the how and why have changed. Network programmability and Software Defined Networking (SDN) take those ideas, analyze the pieces, find ways to improve them for today’s needs, and reassemble those ideas into a new way of making networks work. You have learned about how switches and routers do that forwarding for the entire length of preparing for the CCNA exam. Networking devices forward data in the form of messages, typically data-link frames like Ethernet frames.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |