which cisco certification is best

which cisco certification is best.12.2 Basic Topics 333But they all have some common color markings. Usually red means bad, amber means not so good, and green means good. You should consult the Cisco documentation for details on each product you are running. The "Reference" section at the end of this chapter provides some valuable links to help you identify and correct problems in your network, some of which are verified using port LEDs.After verifying the physical connection, you can verify it in two directions. Verification from the client back to the controller. Verification from the controller to the client. Both of these situations present common problems. You may find that connection problems are not related to the wireless network at all, but to the distributeddistributed network, a gateway, or an Internet Service Provider (ISP,InternetServiceProvider). In any case, the ability to isolate the problem is a requirement for obtaining a CCNA wireless certificate. The next section examines some common client-side issues.20.2.2 Common Client-Side Problems Client-side problems often occur and often manifest themselves in vague ways, for example, "I can't access the Internet anymore," so "you may be thinking, "What does that mean? " The answer may not always be clear, but you can verify some values to restore connectivity for the end user as soon as possible.Note: When I worked for a large service provider, we went through a transition from a bridge to a switch. In the initial deployment, none of the LAN administrators had heard of the Spanning Tree Protocol ( STP,Spanning TreeProtocol) or the impact it had when devices were connected to switch ports.I remember that first week, sitting in my office at 07:55 a.m., hearing my co-workers say, "The Internet is not connecting." Then, naturally, someone called the IT department and said that no one (nobody) could get on the Internet, and he thought there was a problem with the Internet. I feel sorry for these IT people because no one called them and said, "When I came in this morning and turned on the computer, when I verified that there was no loop, Spanning Tree put all the ports in blocking mode, so no one was able to connect to the Internet for about a minute. PortFast, and that would solve the problem. What's my point? Users don't have to call and give you an answer that will solve the problem. Instead, they give you a symptom, and no matter how vague the symptom they describe, it's up to you to decide to decipher the real problem. That's enough of my recollection. What can you do to isolate these questions?Some of the more common problems that can be verified are shown below. Check to see if the client NIC is enabled. Many portable computers have hardware converters that internally disable the wireless NIC, which can cause problems.Check that the Service Set Identifiers ( SSID, ServiceSetIdentifiers) are configured correctly.Verify that the client is using a radio that is not enabled on the AP.