[Contents] [Prev] [Next] [Report an Error]

E

E1 — High-speed WAN digital communication protocol that operates at a rate of 2.048 Mbps.

E3 — High-speed WAN digital communication protocol that operates at a rate of 34.368 Mbps and uses time-division multiplexing to carry 16 E1 circuits.

EAL3 — Common Criteria Evaluation Assurance Level 3. Evaluation Assurance Level is an assurance and compliance requirement defined by Common Criteria. Higher levels have more stringent requirements. See also Common Criteria.

early packet discard — See EPD.

EBGP — External BGP. A BGP configuration in which sessions are established between routers in different autonomous systems (ASs).

E-carrier — “E” stands for European. Standards that form part of the Synchronous Digital Hierarchy (SDH), in which groups of E1 circuits are bundled onto higher-capacity E3 links between telephone exchanges or countries. E-carrier standards are used just about everywhere in the world except North America and Japan, and are incompatible with the T-carrier standards.

ECC — Error checking and correction. The process of detecting errors during the transmission or storage of digital data and correcting them automatically. This usually involves sending or storing extra bits of data according to specified algorithms.

ECSA — Exchange Carriers Standards Association. A standards organization created after the divestiture of the Bell System to represent the interests of interexchange carriers.

edge router — In MPLS, a router located at the beginning or end of a label-switching tunnel. An edge router at the beginning of a tunnel applies labels to new packets entering the tunnel. An edge route at the end of a tunnel removes labels from packets exiting the tunnel. see also MPLS.

editor macros (Emacs) — Shortcut keystrokes used within the router’s command-line interface (CLI). These macros move the cursor and delete characters based on the sequence you specify.

EGP — Exterior gateway protocol; for example, BGP.

egress router — In MPLS, the last router in a label-switched path (LSP). See also ingress router.

EIA — Electronic Industries Association. A United States trade group that represents manufacturers of electronic devices and sets standards and specifications.

EIA-530 — Serial interface that employs the EIA-530 standard for the interconnection of DTE and DCE equipment.

EIR — Equipment identity register. A mobile network database that contains information about devices using the network.

electromagnetic interference — See EMI.

electrostatic discharge — See ESD.

embedded OS software — Software used by a Juniper Networks router to operate the physical router components.

EMI — Electromagnetic interference. Any electromagnetic disturbance that interrupts, obstructs, or otherwise degrades or limits the effective performance of electronics or electrical equipment.

Encapsulating Security Payload — See ESP.

end system — In IS-IS, a network entity that sends and receives packets.

EPD — Early packet discard. For ATM2 interfaces only, a limit on the number of transmit packets that can be queued. Packets that exceed the limit are dropped. See also queue length.

ERO — Explicit Route Object. An extension to RSVP that allows an RSVP PATH message to traverse an explicit sequence of routers that is independent of conventional shortest-path IP routing.

error checking and correction — See ECC.

errored frame — A frame with one or more bits with errors. This frame will be dropped at the next Ethernet node and become a lost frame.

errored second — A period of a second with one or more errored or lost frames.

ESD — Electrostatic discharge. Stored static electricity that can damage electronic equipment and impair electrical circuitry when released.

ES-IS — End System–to–Intermediate System. Protocol that resolves Layer 3 ISO network service access points (NSAPs) to Layer 2 addresses. ES-IS resolution is similar to the way ARP resolves Layer 2 addresses for IPv4.

ESP — Encapsulating Security Payload. A protocol for securing packet flows for IPSec using encryption, data integrity checks, and sender authentication, which are added as a header to an IP packet. If an ESP packet is successfully decrypted, and no other party knows the secret key the peers share, the packet was not wiretapped in transit. See also AH.

Established — BGP neighbor state that represents a fully functional BGP peering session.

Ethernet — Local area network (LAN) technology used for transporting information from one location to another, formalized in the IEEE standard 802.3. Ethernet uses either coaxial cable or twisted-pair cable. Transmission speeds for data transfer range from the original 10 Mbps, to Fast Ethernet at 100 Mbps, to Gigabit Ethernet at 1000 Mbps.

ETSI — European Telecommunications Standardization Institute. A nonprofit organization that produces voluntary telecommunications standards used throughout Europe.

European Telecommunications Standardization Institute — See ETSI.

eventd — Event policy process that performs configured actions in response to events on a routing platform that trigger system log messages.

event policy process — See eventd.

exact — JUNOS software routing policy match type that represents only the route specified in a route filter.

exception packet — IP packet that is not processed by the normal packet flow through the Packet Forwarding Engine. Exception packets include local delivery information, expired TTL packets, and packets with an IP option specified.

Exchange — OSPF adjacency state in which two neighboring routers are actively sending database description packets to each other to exchange their database contents.

exclusive or — See XOR.

EXP bits — Experimental bits, also known as the class-of-service (CoS) bits, located in each MPLS label and used to encode the CoS value of a packet as it traverses an LSP.

explicit path — See signaled path.

Explicit Route Object — See ERO.

export — Placing of routes from the routing table into a routing protocol.

ExStart — OSPF adjacency state in which the neighboring routers negotiate to determine which router is in charge of the synchronization process.

Extensible Markup Language — See XML.

Extensible Stylesheet Language for Transformations — See XSLT.

exterior gateway protocol — See EGP.

external BGP — See EBGP.

external metric — Cost included in a route when OSPF exports route information from external autonomous systems. There are two types of external metrics: Type 1 and Type 2. Type 1 external metrics are equivalent to the link-state metric; that is, the cost of the route, used in the internal autonomous system. Type 2 external metrics are greater than the cost of any path internal to the autonomous system.

[Contents] [Prev] [Next] [Report an Error]