tailieunhanh - CompTIA Network+ Certification Study Guide part 29

CompTIA’s Network+ certification Study Guide part 29 is a globally-recognized, vendor neutral exam that has helped over 235,000 IT professionals reach further and higher in their careers. The 2009 Network+ exam (N10-004) is a major update with more focus on security and wireless aspects of networking. Our new study guide has been updated accordingly with focus on network, systems, and WAN security and complete coverage of today’s wireless networking standards. | 266 CHAPTER 6 The OSI Model and Networking Protocols to in some documentation as the NetBIOS protocol . NetBT supplies the programming interface provided for by NetBIOS along with communication protocols provided for by TCP. NetBT s name service allows host computers to attain and retain or defend a NetBIOS name. It also assists other hosts in locating a computer with a specific NetBIOS name. In addition the name service resolves a specific NetBIOS name to an IP address. This process uses broadcast messages that are sent to all hosts on the network. The name service uses UDP Port 137. The session service of NetBT provides for the reliable exchange of messages between two NetBIOS applications typically on two different computers. The session service uses TCP Port 139. The datagram service within NetBT provides connectionless unreliable message delivery between NetBIOS applications via UDP Port 138. As mentioned earlier when data length is short or reliability is not critical the datagram service is a faster method than session-based communication. Together the session and datagram services provide the NetBIOS applications with the capability to exchange information with one another. However in an environment where Windows Vista and Windows 2008 are the desktop and network operating systems NetBIOS or NetBT IP are replaced by DNS which has become the primary naming and name resolution provider. Exam Warning Remember the following for the Network exam The name service uses UDP Port 137 The datagram service uses UDP Port 138 The session service uses TCP Port 139 WINS WINS is a NetBIOS name server that NetBIOS clients can use to attain register and resolve NetBIOS names. WINS is specific to Microsoft networks and is not used or available for use on non-Microsoft operating system-based computers. Computers running UNIX Linux and other non-Microsoft operating systems typically use DNS for name resolution although there Networking Protocols 267 are other non-WINS NetBIOS .