Extreme Automatic Protection Switching. This is an Extreme Networks-proprietary version of the Ethernet Automatic Protection Switching protocol that prevents looping Layer 2 of the network. This feature is discussed in RFC 3619.

EAPS domain

An EAPS domain consists of a series of switches, or nodes, that comprise a single ring in a network. An EAPS domain consists of a master node and transit nodes. The master node consists of one primary and one secondary port. EAPS operates by declaring an EAPS domain on a single ring.

EAPS link ID

Each common link in the EAPS network must have a unique link ID. The controller and partner shared ports belonging to the same common link must have matching link IDs, and not other instance in the network should have that link ID.


EAP-TLS Extensible Authentication Protocol - Transport Layer Security. A general protocol for authentication that also supports multiple authentication methods, such as token cards, Kerberos, one-time passwords, certificates, public key authentication and smart cards.

IEEE 802.1x specifies how EAP should be encapsulated in LAN frames.
In wireless communications using EAP, a user requests connection to a WLAN through an access point, which then requests the identity of the user and transmits that identity to an authentication server such as RADIUS. The server asks the access point for proof of identity, which the access point gets from the user and then sends back to the server to complete the authentication. 

EAP-TLS provides for certificate-based and mutual authentication of the client and the network. It relies on client-side and server-side certificates to perform authentication and can be used to dynamically generate user-based and session-based WEP keys.
EAP-TTLS (Tunneled Transport Layer Security) is an extension of EAP-TLS to provide certificate-based, mutual authentication of the client and network through an encrypted tunnel, as well as to generate dynamic, per-user, per-session WEP keys. Unlike EAP-TLS, EAP-TTLS requires only server-side certificates. 
(See also PEAP.)


Exterior Border Gateway Protocol. EBGP is a protocol in the IP suite designed to exchange network reachability information with BGP systems in other autonomous systems. EBGP works between different ASs.


Equal Cost Multi Paths. This routing algorithm distributes network traffic across multiple high-bandwidth OSPF, BGP, IS-IS, and static routes to increase performance. The Extreme Networks implementation supports multiple equal cost paths between points and divides traffic evenly among the available paths.

edge ports

In STP, edge ports connect to non-STP devices such as routers, endstations, and other hosts.

edge safeguard

Loop prevention and detection on an edge port configured for RSTP is called edge safeguard. Configuring edge safeguard on RSTP edge ports can prevent accidental or deliberate misconfigurations (loops) resulting from connecting two edge ports together or from connecting a hub or other non-STP switch to an edge port. Edge safeguard also limits the impact of broadcast storms that might occur on edge ports. This advanced loop prevention mechanism improves network resiliency but does not interfere with the rapid convergence of edge ports. For more information about edge safeguard, see Configuring Edge Safeguard in the ExtremeXOS 21.1 User Guide.


Extreme Discovery Protocol. EDP is a protocol used to gather information about neighbor Extreme Networks switches. Extreme Networks switches use EDP to exchange topology information.


Electrically erasable programmable read-only memory. EEPROM is a memory that can be electronically programmed and erased but does not require a power source to retain data.


Exterior Gateway Protocol. EGP is an Internet routing protocol for exchanging reachability information between routers in different autonomous systems. BGP is a more recent protocol that accomplishes this task.

election algorithm

In ESRP, this is a user-defined criteria to determine how the master and slave interact. The election algorithm also determines which device becomes the master or slave and how ESRP makes those decisions.


Extreme Loop Recovery Protocol. ELRP is an Extreme Networks-proprietary protocol that allows you to detect Layer 2 loops.


Extreme Link Status Monitoring. ELSM is an Extreme Networks-proprietary protocol that monitors network health. You can also use ELSM with Layer 2 control protocols to improve Layer 2 loop recovery in the network.


Extreme Multiple Instance Spanning Tree Protocol. This Extreme Networks-proprietary protocol uses a unique encapsulation method for STP messages that allows a physical port to belong to multiple STPDs.


Event Management System. This Extreme Networks-proprietary system saves, displays, and filters events, which are defined as any occurrences on a switch that generate a log message or require action.

encapsulation mode

Using STP, you can configure ports within an STPD to accept specific BPDU encapsulations. The three encapsulation modes are:
  • 802.1D—This mode is used for backward compatibility with previous STP versions and for compatibility with third-party switches using IEEE standard 802.1D.
  • EMISTP—Extreme Multiple Instance Spanning Tree Protocol mode is an extension of STP that allows a physical port to belong to multiple STPDs by assigning the port to multiple VLANs.
  • PVST+—This mode implements PVST+ in compatibility with third-party switches running this version of STP.



Extreme Standby Router Protocol. ESRP is an Extreme Networks-proprietary protocol that provides redundant Layer 2 and routing services to users.

ESRP-aware device

This is an Extreme Networks device that is not running ESRP itself but that is connected on a network with other Extreme Networks switches that are running ESRP. These ESRP-aware devices also fail over.

ESRP domain

An ESRP domain allows multiple VLANs to be protected under a single logical entity. An ESRP domain consists of one domain-master VLAN and zero or more domain-member VLANs.

ESRP-enabled device

An ESRP-enabled device is an Extreme Networks switch with an ESRP domain and ESRP enabled. ESRP-enabled switches include the ESRP master and slave switches.

ESRP extended mode

ESRP extended mode supports and is compatible only with switches running ExtremeXOS software exclusively.

ESRP group

An ESRP group runs multiple instances of ESRP within the same VLAN (or broadcast domain). To provide redundancy at each tier, use a pair of ESRP switches on the group.

ESRP instance

You enable ESRP on a per domain basis; each time you enable ESRP is an ESRP instance.


A VLAN that is part of an ESRP domain, with ESRP enabled, is an ESRP VLAN.


Extended Service Set. Several Basic Service Sets (BSSs) can be joined together to form one logical WLAN segment, referred to as an extended service set (ESS). The SSID is used to identify the ESS. (See BSS and SSID.)


This is the IEEE 802.3 networking standard that uses carrier sense multiple access with collision detection (CSMA/CD). An Ethernet device that wants to transmit first checks the channel for a carrier, and if no carrier is sensed within a period of time, the device transmits. If two devices transmit simultaneously, a collision occurs. This collision is detected by all transmitting devices, which subsequently delay their retransmissions for a random period. Ethernet runs at speeds from 10 Mbps to 10 Gbps on full duplex.


Any type of occurrence on a switch that could generate a log message or require an action. For more, see syslog.

external table

To route traffic between autonomous systems, external routing protocols and tables, such as EGP and BGP, are used.