Device and method for automatically acquiring effective ip configuration in local area network

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to a network, and more particularly to a device and method for automatically obtaining a valid IP configuration in a LAN and in a network test device.

【0002】

[Conventional technology]

In an exchange network configuration, there are problems with how to obtain the IP address of the device connected to the network and how to check the validity of the IP address of the device on the network. In an exchange environment, a port only sees the limited traffic that passes through it (generally only the traffic that is sent to that port), and the amount of data that can be monitored is limited. Alternatively, often only broadcast traffic is visible on the port to which the device is connected.

【0003】

The device wants to select a valid IP address to use when operating on the network. However, in modern networks, inaccurate subnet masks and misconfigured IP addresses are constantly occurring, and monitoring network traffic can result in conflicts and overlapping results. It can be difficult to identify the correct range of local addresses. If that device happens to select an address that is already in use by another device on the network, another network device will illegally update its address cache due to the accidental selection of that IP address. As a result, traffic destined for the original valid owner of the IP address may be lost or mistransmitted. This is highly undesirable, but especially desirable for test equipment that should not itself cause problems on the network.

【0004】

In addition, proper subnet mask and default router selection by the device is essential. This is because if the mask and router are incorrect, the device will not be able to communicate properly with other devices on the network. Choosing the right domain name server (DNS) is also important. The domain name server returns an IP address that corresponds to a symbolic name that is easier for the user to remember than an encrypted IP address. If DNS is chosen improperly, name resolution will not occur if the DNS does not know the IP address associated with a particular name. The device may not even be able to communicate with improperly selected DNS.

【0005】

A particular network may also use a subnet mask that masks the IP address with a mask value to get the range of IP addresses (for example, ABC64 to ABC127). Valid IP addresses for this subnet range from 64 to 127 at the end of the address. If the test device (or other device) is not using an IP address within this range (for example, ABC250, which is outside the range 64 to 127), there will be no response from other devices on the network. .. This is because other devices send packets to the router indefinitely to forward to the network where this IP address (ABC250 in this example) should be, so no data is received by this device.

【0006】

Traditionally, when one contiguous range of IP addresses was used in a given network, IP addresses outside this range had to go through the router. But nowadays, many discontinuous IP address ranges are usually on the same network cable. It can be difficult to determine which range is valid.

【0007】

Traditional test equipment requires the user to provide the IP address used by the equipment, requires a certain level of network knowledge, and that no equipment is improperly configured with an invalid IP address. It was a premise. Two or more devices with duplicate IP addresses can cause intermittent network problems. For example, in Ethernet®, IP addresses are resolved by hardware addresses (MAC (Media Access Controller) addresses). Individual devices maintain an ARP cache (address resolution protocol) for MAC addresses (typically 48 bits) so that ARP is not required each time the network is accessed. When ARP is performed on an IP address used by two or more hosts on the network, there are multiple responses and the ARP cache of the other host on the network is updated indefinitely. As a result, the MAC address in the ARP cache changes frequently, and frames sent to duplicate IP addresses go to the wrong device part at that time. The host then occasionally updates the ARP cache so that the mapping of the IP address to the MAC address indicates the "desired owner" of the IP address. At this point, updating the ARP cache directs the transmission to the appropriate device. As a result, communication happens to start working again for reasons that are not easily understood (by the user). This situation should be avoided if possible, as the test equipment must not compromise the network.

【0008】

[Problems to be Solved by the Invention]

According to the present invention, that is, the method of automatically obtaining the IP configuration when the configuration cannot be obtained by DHCP (Dynamic Host Configuration Protocol), the traffic is continuously monitored and the subnet mask, local. Identify the local addresses that correspond to routers and servers. The collected information is stored in the database, and after a certain period of time, the valid IP subnet and the invalid IP subnet are determined.

【0009】

Therefore, an object of the present invention is to provide an improved network test device that automatically obtains a valid IP configuration without damaging other network hosts or the like. Further, an object of the present invention is to provide an improved method for automatically acquiring a valid IP configuration of a portable network device.

【0010】

[Means for solving problems]

To solve the above problems, the method of automatically obtaining a valid IP configuration within the local area network of the present invention monitors network traffic and validates at least one IP subnet. It includes a monitoring step, a selection step to select an IP address that is likely to be unused within at least one IP subnet, and a decision step to determine if the selected IP address is unused. ..

【0011】

In addition, the device that automatically obtains a valid IP configuration within the local area network of the present invention includes a network traffic monitor for monitoring and validation of at least one IP subnet, and at least one. It has an IP address selector for selecting an IP address that is likely to be unused in the IP subnet and determining whether the selected IP address is unused.

【0012】

The subject matter of the present invention is specifically pointed out at the end of the specification and is explicitly claimed. However, the organization and method of operation, as well as other advantages and objectives, can be better understood by reading the following instructions in conjunction with the accompanying drawings. In drawings, the same reference symbol refers to the same element.

【0013】

BEST MODE FOR CARRYING OUT THE INVENTION

A system according to a preferred embodiment of the present invention comprises network analytical instruments and methods capable of automatically obtaining a valid IP configuration. FIG. 1 is a perspective view of a typical network test device according to the present invention. The test device 10 shown in FIG. 1 is appropriately configured as a portable device for network testing and analysis. The display 12 allows interaction between the user and the test device 10. The display is appropriately a touch screen display, and the stylus 14 can be used by the user in interaction with the test device 10. Various status indicators 16 are provided along the top of the case to indicate link status, transmissions, conflicts, errors, utilization, and more. A power button 18 is also provided. The test equipment 10 is suitable to be powered by an internal battery system, but can also be connected to an external power source. The test device 10 has a function as a network traffic monitor and a function as an IP address selector.

【0014】

FIG. 2 is a high-level block diagram of the test device 10. The microprocessor 20 is connected to a touch screen 12 that displays and receives information. The memory 22 is connected to the microprocessor 20. FPGA (Field Programmable Gate Array) 24 is also connected to microprocessor 20. The network interface unit 28 handles the actual transmission and reception details with and from the network.

【0015】

FIG. 3, FIG. 4, and FIG. 5 are flow charts of steps executed by the test device 10 to which the present invention is applied. As shown in FIG. 3, when the test device 10 is connected to the network, the test device 10 first starts monitoring the network traffic (step 100). As described in more detail below, test equipment 10 continuously monitors traffic, identifies received information, and stores it in a database.

【0016】

During step 100 monitoring and continuous monitoring, DHCP (Dynamic Host Configuration Protocol) is attempted as soon as a link is detected, attempting to obtain an IP address, in parallel with the monitoring. (Step 102). As is well known in the art, this involves broadcasting a message to locate a DHCP server. If this attempt is successful (decision step 104), the DHCP server responds with an IP address, subnet mask, default router, DNS server, and IP address lifetime, ending the process of retrieving the IP configuration.

【0017】

However, many networks may not have a DHCP server or the server may be temporarily unavailable, due to network behavior issues that network technicians are trying to solve, and therefore the use of test equipment. There may be. According to conventional technology, if DHCP is unsuccessful, traditional devices will continue to try DHCP, either until DHCP succeeds or by the user manually giving a valid IP configuration (which is connected). It is very difficult if the user does not have prior knowledge of the network).

【0018】

According to the test equipment, devices, or methods described herein, the Internet Control Message Protocol (ICMP) address mask remains at zero source IP (0.0.0.0) if DHCP is unsuccessful. The request is sent (step 105). ICMP is a protocol that does many things, including, for example, the ability of routers to notify other hosts of IP configuration information. An ICMP address mask request is one of several types of IP packets defined to respond to a zero source IP (0.0.0.0). If the source IP is zero, most IP packets are dropped by the TCP / IP stack. Some even know the address of the host with the corresponding subnet mask, as some respond to ICMP requests and broadcast to 255.255.255.255 and return an answer. Some routing protocols (eg OSPF and RIP2) publish subnet masks.

【0019】

The system continuously monitors traffic on the network and collects information from the traffic and from the responses generated to ICMP requests. Step 106 is executed when the local host is found by the monitoring in step 100, and the host found on the network is placed in the address range. A host is the name given to an addressable device on the network. IP addresses that are not local to the connected network are identified and discarded (for example, most routing protocols and ARP requests are from the local host).

【0020】

Decision step 108 determines if the discovered host reported a subnet mask. If the host reports, the host is placed in a database that contains the host's source IP address and the same subnet mask as the host (step 110). If, as a result of decision step 108, the discovered host does not report a subnet mask, then this particular host contains the source IP of this host and has the largest number of hosts showing a matching subnet mask. It is placed within the address range that is (step 112). After step 110 or 112, determine if sufficient monitoring time has elapsed (step 114), and if not, proceed to step 106 if additional hosts are found. The monitoring time may vary, but can generally include about 20 seconds as an example. The time may be predetermined, but may vary depending on the amount of data available based on network traffic. The low traffic within a given time may suggest a longer monitoring time to obtain a more robust data set. After the time is up, a validation process is performed to determine valid and invalid address ranges (step 116). This process involves checking for overlapping address ranges and determining valid and invalid IP subnets. This decision is made using an optimal agreement based on the number of hosts showing a particular subnet mask. In the next step 118, hosts located within the invalid range are moved to the appropriate reasonable range.

【0021】

Then, after some time (step 122), the collected traffic information is used to select the best address range on the local segment, as shown in Figure 4. In order to select the "optimal" address range, the subnet in which the subnet mask is found, or the subnet in which the router is found, is preferred. Next in the priority hierarchy is to use an IP subnet that contains the majority of hosts. After this local address range is selected, step 124 is performed to select the most likely subnet mask. This subnet mask is only used to select the source IP of the test equipment and may not actually be used (for example, if a better one is found later). To select a subnet mask, if a subnet mask is found as a result of traffic analysis, the found subnet mask is used. If not found, the last user-specified subnet mask is used if it is clear that it is valid in the current network. The final manual configuration is saved in its entirety and can be used if desired. If not, try a very narrow subnet mask and grow until all local addresses in the selected optimal address range fit within the subnet mask, or reach 255.255.255.0. For example, you can try the first subnet mask of 255.255.255.248. If this does not work, that is, if all the local addresses found during monitoring within the selected optimal address range do not fit within the mask, then another least significant bit is allowed in the mask. For example, 255.255.255.240. If this mask and subsequent masks are not appropriate, try the masks one after another as 255.255.255.224, 255.255.255.192, and 255.255.255.128. Finally the mask is 255.255.255.

【0022】

In the next step 126, test equipment 10 attempts to find the source IP. Initially the IP is set using the start octet value, which may be preselected by the user for a particular value, but if the user of test equipment 10 does not, 250 is the appropriate default. It becomes the start value. Therefore, given a particular "optimal" IP address range ABCXXX, the start octet value is replaced with XXX and the subnet mask is assigned to the ABCXXX value. It then inspects the discovery database (the database of IP addresses and other information found or "discovered" on this particular network by test equipment 10) (judgment step 128), and its source IP is on the network. Check if it is active. A, B, and C indicate the IP address value, which depends on the network to which the device is connected. For example, if the ABC for a particular network is 260.83.10 and the subnet is in the range .128 to .191, the device will take 260.83.10.128 and 250 of the start octets assigned to that mask (default start). Add octet 250 and subnet mask 255.255.255.192) to get address 260.83.10.186. The device first checks and finds out if 260.83.10.186 has already been confirmed by looking up the address in the discovery database. If that particular source IP is active, decrement the source IP in step 130 (to 260.83.10.185) and return to decision step 128 to see if this IP is already in the discovery database. Repeat decrement and inspection until a value is determined that is not an active source IP and is within the valid subnet range of the source IP (.128 to .191 in this example).

【0023】

The process then continues to check if the source IP is already in use, for example by "free ARP". The test can optionally be performed by the method described in US Pat. No. 5,724,510 (step 132), the disclosure of which is incorporated herein by reference. Hosts typically maintain an ARP cache, which stores the 48-bit media access control addresses (MAC addresses) of other hosts on the network. However, the desired goal is to avoid ARP cache corruption (which can occur when testing an already used IP address with "free ARP") and generate a console error message in the admin console. Or to avoid the generation of log file errors, an additional double check can be achieved by using an optional step. If the source IP is being used by another host (decision step 134), processing continues at step 130, the XXX area is further decremented, and another source IP is tried. Examining the source IP against an already discovered IP address discovery database speeds up the process of automatically finding an IP address, which is unnecessary due to network requests and attempted availability checks. Network traffic is reduced.

【0024】

On the other hand, if it is determined in the determination step 134 that the source IP is not used, the process proceeds to the step shown in FIG. As shown in Figure 5, in this case the TCP / IP stack responds (because there is a valid source IP), so additional discovery requests are sent over the network to identify the local IP configuration. These requests include, for example, an ICMP Router Solicitation to get more information about the network configuration and the hosts on it, and an ICMP Address Mask, ICMP Echo, SNMP Mask Request, and DNS Discovery Request. )including. These requests are sent to the limited IP broadcast address, 255.255.255.255, to quickly request a response from all localhost.

【0025】

After processing these additional discovery requests, test equipment 10 selects the best default router found, the best subnet mask, and the best DNS server (step 138). All router IP addresses in the same address range as the test equipment are compared to determine the best default router. The preferred router is selected based on the routing protocol used. For example, in a preferred embodiment, the OSPF (Open Shortest Path First) protocol is given a high rank, followed by EIGRP (Enhanced Interior Gateway Routing Protocol) and the like. Other protocols below the hierarchy are RIP (Routing Information Protocol) and IRDP (ICMP Router Discovery). Protocol). If multiple IP addresses with the same routing protocol priority are found in the hierarchy, the lower IP address is selected. The DNS server selected is the lowest DNS server IP address in the same address range as the test equipment. However, if a DNS server is not found in the same address range as test device 10, some found DNS server is selected. If no DNS server is found, the DNS server will be used from the last user-specified configuration.

【0026】

After the test device 10 or other device has completed the automatic IP configuration process, a periodic timer can be started to occasionally validate and correct the configuration. It is suitable to use only when using fully automated configuration. If the configuration is set manually or partially assisted by the user, it is preferable to omit the automatic correction. As for the periodic timer, 5 seconds is suitable in a preferred embodiment, and it is suitable that the automatic correction process can be stopped after a long time, for example, 5 minutes.

【0027】

Test equipment 10 then automatically performs a segment discovery test in parallel with the autocorrection step described above to analyze all network equipment within the broadcast domain (part of the network receiving the same broadcast). Can detect local hosts, switches, routers, servers, and other network devices. Therefore, other addressing information such as IP address, MAC address, subnet mask, etc. are also found appropriately. This is appropriate to do with unicast traffic, as some devices may not respond to the broadcast. A detailed database of various devices and networks will be compiled. The auto-correction process uses the database to update the IP configuration when a more suitable router, DNS server, or appropriate subnet mask is identified.

【0028】

FIG. 6 shows an example of validation in a particular situation, a graph showing address ranges and host locations with multiple discontinuous groups of address ranges with corresponding subnet masks. In Figure 6, a large number of valid hosts are in the address range 50. In addition, some hosts are in address ranges 52 and 54, while significantly more hosts are in address range 56 (still less than the number of hosts in range 50). In the situation shown in FIG. 6, all address ranges are validated and the address range within region 50 is selected as the "optimal" address range.

【0029】

FIG. 7 is a graph showing validation in another possible situation. In this configuration, a group of hosts is contained within the boundaries of address range 58, which is completely contained within large address range 60. In this configuration, the hosts in the address range 58 are validated, while the hosts in the ranges 62 and 64 are left unvalidated because they are collision information.

【0030】

In the validation process, the host is initially placed where the host indicates it belongs. After validation, the host is placed within the first valid address range in which it fits. If there is no valid address range that a host can fit in, then if the host has a subnet mask, it will be placed where the host indicates it needs to be placed, or most hosts that the host will fit in will have an address range. Placed inside.

【0031】

As described above, according to the present invention, a device and a method for automatically acquiring an effective IP configuration have been shown and described. This allows the test equipment to obtain an IP address without causing network problems on the network. Although the illustrated embodiment has been described mainly in the case of a network test device, the present invention is also applied to other devices that can be appropriately connected to the network to automatically acquire the IP configuration. For example, a portable computer using the method or device of the present invention (laptop, notebook, etc.) can conveniently connect to a network to automatically obtain an IP configuration.

【0032】

Having shown and described a preferred embodiment of the invention, it will be apparent to those skilled in the art that numerous modifications and modifications can be made to the invention without departing from the broader aspects of the invention. Accordingly, the appended claims include all such changes and modifications that fall within the true spirit and scope of the invention.

[Simple explanation of drawings]

[Figure 1]

FIG. 5 is a perspective view of a test device to which the method of the present invention for automatically acquiring a valid IP configuration is applied.

[Figure 2]

It is a high-level block diagram of the test equipment to which this invention is applied.

[Fig. 3]

It is a flow chart of a step to acquire an IP configuration.

[Fig. 4]

It is a flow chart of another step to acquire an IP configuration.

[Fig. 5]

It is a flow chart of another step to acquire an IP configuration.

[Fig. 6]

It is a graph which shows the validation of the address range and the selection of the "optimal" address range in one possible situation.

[Fig. 7]

It is a graph which shows the validation of the address range in another possible situation.

[Explanation of symbols]

10 Network equipment 12 touch screen 14 stylus 16 Status indicator 18 Power button 20 microprocessor 22 memory 24 gate array 28 Network interface section