Node Type of NetBIOS protocol

We all know that NetBIOS has many applications and problems. We will introduce the node issues in use in detail today. First, let's take a look at the NetBIOS node types.

NetBIOS protocol Node Type

The term "nodedesignation" is used to indicate how a computer node parses the name and address of a computer. Each NetBIOS computer has one node type. There are four node types corresponding to four Resolution Methods:

Node B -- only use the broadcast method. This type of node uses broadcast messages on the local subnet to discover computers in the same subnet.

Broadcast Node B) parses the computer name and address in the LAN subnet only through broadcast datagram, that is, its valid range is only its subnet. The client sends a broadcast message to its local subnet. The message contains the IP address of the computer to be searched and its MAC address. Because broadcast is used, all computers on the Internet will receive the data. If the computer with the address specified in the datagram exists, then it will respond to the MAC address of the computer containing the message in this datagram. In this way, the computer will cache frequently used MAC addresses and use these addresses for direct communication with remote computers.

Disadvantages of using node B: 1. Increase unnecessary communication traffic on the network, resulting in a large amount of broadcast message flooding. 2. Most routers do not forward these broadcasts, which prevents Node B from parsing the computer on the other side of the router. That is, Node B cannot find the address of a computer other than its subnet.

Solution:

1. Using WINS servers can reduce communication traffic.

2. Use an LMHOSTS or HOSTS file to save the IP address of the computer on the other side of the router to the local NetBIOS name cache, so as to avoid searching through broadcast. Therefore, a complete method for parsing NetBIOS B nodes can be described as follows:

1. query by NetBIOS name cache. If the query succeeds, an IP address is returned to complete resolution. If the query fails, move to the next step:

2. query through broadcast. If the query succeeds, an IP address is returned to complete the resolution. If the query fails, move to the next step:

3. query through the local LMHOSTS and HOSTS files. The resolution is completed whether the file is successful or not.

P node -- only use point-to-point communication with the name server. This type of node uses services such as WINS Server) for query to obtain the address to be parsed.

The P node does not use broadcast to parse the name. Through point-to-point communication, the UDP datagram and TCP conversation are registered to a NetBIOS Name Server (WINS). Therefore, it will directly query the server for address translation, and then directly send the information to the target computer. Therefore, the advantage of P nodes is that it reduces the number of local broadcasts and can communicate with WINS servers located in other subnets across routers.

Disadvantages of using the P-Node Method:

1. The client must know the IP address of the WINS server When configuring the P node.

2. Configure the P node and use the DHCP server.

3. If the WINS server stops service, the P node will lose the ability to parse the name and translation address.

M node -- use broadcast before point-to-point communication. This type of node sends a broadcast message on the LAN to find another computer. If no response is returned or the query fails, it is converted to the p Section to continue the query. It also uses broadcast messages when registering its own name with the name resolution server.

The M node uses broadcast first and communicates directly with the WINS server after resolution fails. Therefore, it is a combination of the two methods described above. In practical applications, computers are rarely configured as such nodes. The only advantage is that most of the services required for a WAN node without a WINS server are in one subnet, that is, communication occurs in the same subnet, which can reduce the information transmission volume of the router. At the same time, even if the WINS server stops service, it can query computers in the local subnet in broadcast mode.

H node-first use point-to-point communication and then use broadcast. This type of node uses the NetBIOS name resolution service for registration or resolution. If the node cannot be connected to the name resolution server (such as the WINS Server), the node B is used for further query.

H node is called a cross node in Windows9x, as shown in the preceding test. In actual application, H node is also called a hybrid node. It is the opposite of M nodes. It first uses P nodes to request the WINS server to parse the computer name. If this method fails, it then uses the broadcast method for parsing.

Therefore, the difference between the H node and the B node is that the H node can resolve all computers registered on the same WINS server through the router.

The difference between the H node and the M node is that if the configured WINS server is not online, the H node will continue to contact it during the parsing process, that is, as long as the WINS server restarts the service, the H node will immediately use the WINS server to parse the computer name, even if it is communicating with the target computer in broadcast mode.

A complete method for parsing NetBIOS H nodes can be described as follows:

1. query by NetBIOS name cache. If the query succeeds, an IP address is returned to complete resolution. If the query fails, move to the next step:

2. query through the WINS server. If the query succeeds, an IP address is returned to complete the resolution. If the query fails, move to the next step:

3. query through broadcast. If the query succeeds, an IP address is returned to complete the resolution. If the query fails, move to the next step:

4. query through the local LMHOSTS and HOSTS files. The resolution is completed whether the file is successful or not.