Browse Prior Art Database

Intelligent MAC/IP Error detection logic

IP.com Disclosure Number: IPCOM000029076D
Original Publication Date: 2004-Jun-15
Included in the Prior Art Database: 2004-Jun-15
Document File: 3 page(s) / 121K

Publishing Venue

IBM

Abstract

Disclosed is an Intelligent MAC/IP Error Detection Logic which not only report duplicate MAC addresses, but also intelligently detect duplicate IP addresses.

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Intelligent MAC/IP Error detection logic

Each network adapter has its own unique manufacturer defined MAC address (Media Access Control). This address is used to uniquely identify the adapters in the network. An invalid MAC address will cause networking problems especially if the invalid address is a duplicate of another address on the same subnet. Each network interface also maintains a unique IP address through out the entire life of the connection. The use of a LAA (Locally Administered address) creates a higher possibility of assigning duplicate MAC addresses to a machine. Invalid MAC or IP (Internet Protocol) addresses due to changes by the user or system administrator or due to other hardware failures will cause many network problems such as lost connectivity,loss of data and ARP (Address Resolution Protocol) storms, which in turn create excessive LAN traffic when a duplicate MAC address is detected. Network devices, like switches, can also be adversely affected:ports taken out of service and packets can be incorrectly routed due to duplicate MAC/IP.

Today, the logic in LAN adapters only reports duplicate MAC addresses through an event interrupt. It does not give any detailed data. With no data, there is not an easy way to determine the source of the duplicate MAC address. The network administrators spend significant amounts of time trying to locate the source of the duplicate MAC address.

LAN (Local Area Network) adapter logic does not have the knowledge to uncover duplicate IP addresses. It is not easy to figure out if an IP address is a duplicate since the duplicate address can happen intermittently say when someone adds/removes their system from the network or in the event of a hardware error or if someone is eavesdropping on the network. The logic proposed here will allow you to detect duplicate MAC and IP addresses reliably.

The proposed solution is to enhance the address detection logic on the adapter to not only report duplicate MAC addresses, but also "intelligently" detect duplicate IP addresses. The adapter will need to read the IP and MAC address of incoming packets and compare it to all MAC and IP addresses from previous packets that it had received to determine whether or not a MAC or IP address has been duplicated. With this enhanced logic, network administrators can use the "enhanced" network adapter as a scan tool allowing them to monitor the network traffic to solve network problems due to duplicate MAC/IP addresses. The scan tool can be designed in either hardware via a special network adapter or in software by utilizing any adapter in a network as a monitoring device. With this new tool, the information it provides will enable network administrators to quickly and easily resolve network issues.

The network adapter will not only read the first 6 bytes of an incoming packet, it will read further into the IP header to find the source and destination IP of the packet as shown below.

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Destination...