NetBIOS is an API developed in the early 1980s by IBM to allow applications on separate computers to communicate over a network. Although NetBIOS usually runs over
Name Service
Typically, NetBIOS uses broadcasts to register its name on the network. In effect, this service works like a dynamic peer-to-peer DNS. Modern networks implement a centralized name server (Microsoft’s WINS service, for example) to overcome the drawbacks of a broadcast-based name service. NetBIOS over TCP/IP operates the Name Service over 137/UDP.
Session Service
The Session Service provides a method for two devices to establish a connection. Once the connection is established , the Session Service exchanges data between the two end points. NetBIOS over TCP/IP operates the Session Service over 139/TCP.
Datagram Distribution Service
The Datagram Distribution Service handles connectionless communication between devices. This service can send packets to a unique name or broadcast. NetBIOS over TCP/IP operates the Datagram Distribution Service over 138/UDP.
SMB is the network protocol used for file and printer sharing in Windows-based networks. Althought they are often confused, it’s important to note that SMB and NetBIOS are not the same thing. SMB works at a higher layer than NetBIOS and uses both the Session and Datagram Distribution Services to exchange data.
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May 13th, 2007 at 4:30 am
[...] a Metro Ethernet network, the possibility exists for a lot of NetBIOS broadcasts if your users are connecting directly to the ring rather than through a firewall. My [...]