ccna test dumps 200-125

ccna test dumps 200-125.All devices connected to the same hub belong to the same conflict domain; unlike hubs, switches cannot increase the coverage of conflict domains. Instead, they create multiple conflict domains a port is all a ^worm-standing conflict domain, so switches create more and smaller conflict domains, thus increasing the bandwidth of the network. To intelligently exchange (forward) frames, the switch learns the interface associated with the MAC address and stores this information in a content addressable memory (CAM) table (port address table). The switch always floods (sends them out of all interfaces except the receiving port) such frames as the following: unicast, multicast, and local broadcasts with unknown destination addresses. Because of this interconnectivity, the MAC addresses of all devices in a Layer 2 switched network must be unique_free.Practical experience If devices are located in different broadcast domains, their MAC addresses can be the same.Switches can also have MAC addresses; they are required in order for the Spanning Tree Protocol (STP) to elect the root switch and to communicate directly with the switch for remote management. Given that redundancy may be important, loops may exist in Layer 2 switched networks. The MAC address associated with the switch usually comes from the switch backplane or from a monitoring module installed in the switch: the switch port itself usually does not have a MAC address.Chapter 9 Sending and Receiving TCP/IP Packets9.1.3 Layer 3 DevicesA router is the primary Layer 3 network device that connects different broadcast domains (Ethernet segments or VLANs). Logical addresses are used to implement hierarchical scalable networks; TCP/IP is one protocol that uses logical addressing. As described in Chapter 6, IP addresses contain two parts: the network part and the host part, and subnet masks are used to distinguish between these two parts.One of the main responsibilities of a router is to find the best path to a destination and to exchange packets correctly. The router stores a list of Layer 3 destination networks and subnets in the routing table, which, as you will see in Chapter 14, can contain both manually entered entries (static routes) and entries learned using dynamic routing protocols; the router automatically shares the networks and their locations among these entries.1. Default GatewayTo communicate with devices in other broadcast domains (i.e., other networks), you must know which default gateway to forward traffic to. The default gateway is actually the router that knows how to forward traffic from the current broadcast domain to the remote destination. Local devices need to be dynamically informed or statically configured with a default gateway.One way to determine if the host knows the default gateway is to ping the default gateway's address on the host. If successful, then try pinging other addresses on that default gateway router (addresses located in other subnets). If this fails, you can be sure that the default gateway is working properly and that the PC may not have a default gateway address configured. If you see a "Target device unreachable" message - an Internet Control Message Protocol (ICMP) answer from a Layer 3 device - there is a network problem that is causing the ping to fail to reach the target device; if you see a If you see a "request timed out" message, the device did not receive any ICMP answers. 2.