Network Glossary E

E1 A name used for DS1 lines inside the European TDM hierarchy.

E1 route (OSPF) An OSPF external route for which internal OSPF cost is added to the cost of the route as it was redistributed into OSPF.

E2 route (OSPF) An OSPF external route for which internal OSPF cost is not added to the cost of the route as it was redistributed into OSPF.

E3 A name used for DS3 lines inside the European TDM hierarchy.

EAP See Extensible Authentication Protocol.

EAP over LAN The encapsulation of EAP messages directly inside LAN frames. This encapsulation is used between the supplicant and the authenticator.

EAPoL See EAP over LAN.

eBGP See External BGP.

eBGP multihop A BGP feature that defines the IP TTL field value in packets sent between two eBGP peers. This feature is required when using IP addresses other than the interface IP address on the link between peers.

edge LSR An MPLS LSR that can forward and receive both labeled and unlabeled packets.

EF See Expedited Forwarding.

EGP See Exterior Gateway Protocol.egress PE An E-LSR in an MPLS VPN network whose role in a particular discussion is to receive labeled packets from other LSRs and then forward the packets as unlabeled packets to CE routers.

ELMI See Enhanced Local Management Interface.

E-LSR See edge LSR.

enable password The password required by the enable command. Also, this term may specifically refer to the password defined by the enable password command.

enable secret The MD5-encoded password defined by the enable secret command.

encapsulation The process of taking a PDU from some other source and placing a header in front of the original PDU, and possibly a trailer behind it.

encoding The process of changing the electrical characteristics on a transmission medium, based on defined rules, to represent data.

enhanced editing The Cisco IOS feature by which special short key sequences can be used to move the cursor inside the current command line to more easily change a command.

Enhanced Local Management Interface A Cisco-proprietary LMI protocol, implemented in Cisco WAN switches and routers, through which the switch can inform the router about parameters for each VC, including CIR, Bc, and Be.

ESF See Extended Superframe.

established A BGP neighbor state in which the BGP neighbors have stabilized and can exchange routing information using BGP Update messages.

EUI-64 A specification for the 64-bit interface ID in an IPv6 address, composed of the first half of a MAC address, hex FFFE, and the last half of the MAC.

exceed A category used by a policer to classify packets relative to the traffic contract. With two-color policers, these packets are considered to be above the contract; for three-color, these packets are above the Bc setting, but within the Be setting.

Excess Burst With shaping and policing, the number of additional bits that may be sent after a period of relative inactivity.

expedite queue A term used with Cisco LAN switches, referring to a queue treated with strict-priority scheduling.

Expedited Forwarding A DiffServ PHB, based on DSCP EF (decimal 46), that provides low-latency queuing behavior as well as policing protection to prevent EF traffic from starving queues for other types of traffic.

Extensible Authentication Protocol Defined in RFC 3748, the protocol used by IEEE 802.1X for exchanging authentication information.

Exterior Gateway Protocol An exterior routing protocol that predates BGP. It is no longer used today.

exponential weighting constant Used by WRED to calculate the rate at which the average queue depth changes as compared with the current queue depth. The larger the number, the slower the change in the average queue depth.

Extended Superframe An enhanced version of T1 framing, as compared with the earlier Superframe (D4) standard.

External BGP A term referring to how a router views a BGP peer relationship, in which the peer is in another AS.

external route From the perspective of one routing protocol, a route that was learned by using route redistribution.