ICMP (Internet Control Message Protocol)
IP-level protocol for reporting errors and status information supporting the function of troubleshooting utilities such as ping.
IDE (Integrated Development Environment)
A programming environment that typically includes a code editor containing an autocomplete feature to help you write code, a debugger to help you find coding errors, and an interpreter that translates the script file code into machine readable code the computer can execute.
IDS (Intrusion Detection System)
Software or security appliance designed to monitor network traffic (NIDS) or configuration files and logs on a host (HIDS) to record and detect unusual activity. Many systems can automatically take preventive action (Intrusion Prevention System [IPS]).
Detection is either signature-based or anomaly-based (or both). IDS software typically requires a lengthy period of configuration and "training" to recognize baseline "normal" activity.
IMAP (Internet Message Access Protocol)
A TCP/IP application protocol providing a means for a client to access email messages stored in a mailbox on a remote server. Unlike POP3, messages persist on the server after the client has downloaded them. IMAP also supports mailbox management functions, such as creating subfolders and access to the same mailbox by more than one client at the same time. IMAP4 utilizes TCP port number 143.
IMEI (International Mobile Equipment Identity) number
A number that uniquely identifies a mobile device on a GSM (Global System for Mobile Communication) network.
IMSI (International Mobile Subscriber Identity) number
A number that uniquely identifies a mobile subscriber.
IPS (in-plane switching)
An LCD panel technology designed to resolve the quality issues inherent in TN panel technology, including strong viewing angle dependence and low-quality color reproduction.
IPSec (Internet Protocol Security)
Layer 3 protocol suite providing security for TCP/IP. It can be used in two modes (transport, where only the data payload is encrypted, and tunnel, where the entire IP packet is encrypted and a new IP header added). IPsec can provide confidentiality and/or integrity. Encryption can be applied using a number of hash (MD5 or SHA) and symmetric (DES or AES) algorithms. Key exchange and security associations are handled by the Internet Key Exchange Protocol. Hosts can be authenticated by a shared secret, PKI, or Kerberos.
IRQ (Interrupt Request)
A communications channel between a hardware device and the system processor. Originally, when hardware was added to the computer it had to be manually configured with a unique interrupt number (between 0 and 15). Plug-and-Play compatible systems configure resources automatically. The PCI bus introduced IRQ steering, which allowed IRQs to be shared. Modern computers use programmable interrupt controllers, allowing for hundreds of interrupts.
ISDN (Integrated Services Digital Network
A digital phone/fax/data service used to provide Internet connectivity. There are two classes of ISDN: Basic Rate Interface (BRI) provides two 64 Kbps (B channels) for data and one 16 Kbps (D channel) for link management control signals; Primary Rate Interface (PRI) provides either T1 or E1 capacity levels (23B or 30B) channels, depending on location in the world, and one 64 Kbps D channel.