Glossary
GL-8
Cisco ONS 15454 SDH Troubleshooting and Maintenance Guide, R3.3
May 2002
EML
Element Manager Layer.
EMS
Element Management System.
Envelope
The part of messaging that varies in composition from one transmittal step to another. It identifies the message originator and
potential recipients, documents its past, directs its subsequent movement by the Message Transfer System (MTS), and
characterizes its content.
EOW
(Engineered Orderwire). A permanently connected voice circuit between selected stations for technical control purposes.
ERDI
Enhanced Remote Defect Indicator.
ES
Errored Seconds.
ESD
Electrostatic Discharge.
ESF
Extended Super Frame.
Ethernet switch
A type of Ethernet LAN device that increases aggregate LAN bandwidth by allowing simultaneous switching of packets
between switch ports. Ethernet switches subdivide previously shared LAN segments into multiple networks with fewer stations
per network.
ETSI
European Telecommunications Standards Institute.
Extended SNCP
(Extended Subnetwork Connection Protection). Extended SNCP extends the protection scheme of a subnetwork connection
protection ring (SNCP) beyond the basic ring configuration to the meshed architecture of several interconnecting rings. See
SNCP.
External timing reference
A timing reference obtained from a source external to the communications system, such as one of the navigation systems. Many
external timing references are referenced to Coordinated Universal Time (UTC).
Comments to this Manuals