Editing Synchronous optical networking (section)

===TL1/Q3 Protocols===

;TL1
SONET equipment is often managed with the [[TL1]] protocol. TL1 is a telecom language for managing and reconfiguring SONET network elements. The command language used by a SONET network element, such as TL1, must be carried by other management protocols, such as [[Simple Network Management Protocol|SNMP]], [[CORBA]], or [[XML]].
;Q3
SDH has been mainly managed using the Q3 interface protocol suite defined in ITU recommendations Q.811 and Q.812. With the convergence of SONET and SDH on switching matrix and network elements architecture, newer implementations have also offered TL1.<ref>{{Cite web |title= Framework for the Integrated Management of Hybrid Circuit/Packet Networks
| date=2003
|url=https://www.ietf.org/lib/dt/documents/LIAISON/ITU-SG4-M3017.htm |access-date=2023-06-15 |website=www.ietf.org}}</ref>

Most SONET [[network element|NEs]] have a limited number of management interfaces defined:

;TL1 Electrical interface
:The electrical interface, often a [[50 Ω|50-ohm coaxial cable]], sends SONET TL1 commands from a local management network physically housed in the [[telephone exchange|central office]] where the SONET network element is located. This is for local management of that network element and, possibly, remote management of other SONET network elements.