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Installation PTN-2-C37.94 with E1/PTN-2-C37.94 with T1
Release 01 02/2018
1.
INTRODUCTION
1.1
General
This document is valid as of Dragon PTN Release 3.0DR.
E1 and T1 links are used worldwide to implement synchronous TDM links between two end
points. These links typically transport voice and/or data using TDM. The application of E1 or
T1 is country related. T1 is primarily used on the North American continent and Japan
whereas E1 is used in most other areas. Both carriers differ with respect to the physical
interface, the framing algorithm, signaling and network management.
An E1 service bundles together 32 TDM (Time Division Multiplex) channels whereas a T1
service bundles together 24 TDM channels. This results in an E1 service having a total
bandwidth of 2.048 Mbps and a T1 service a total bandwidth of 1.544 Mbps.
C37.94 is a standard for transmitting N times 64 kbps on an optical fiber, where N=1,2,…12.
It is a protocol used in the power industry between teleprotection and multiplexer
equipment. Teleprotection makes sure that faulty parts within a power system will be
disconnected very fast to prevent further damage within that power system. A C37.94 frame
also has a bandwidth of 2.048 Mbps and all its information is also transported in 32
timeslots, just like E1. But C37.94 is a special kind of E1 framing. Within these 32 E1
timeslots, C37.94 has its own timeslot mapping and uses N (=1 to 12) timeslots for real data,
see §2.2.4.
HiProvision (=Dragon PTN Management System) has two variants of this IFM (see also
§2.3.2b):
2-C37.94-E1-L = 2-C37.94 IFM in E1 mode;
2-C37.94-T1-L = 2-C37.94 IFM in T1 mode;
This IFM converts the C37.94/E1/T1 framing from a C37.94/E1/T1 link into MPLS-TP packets
over the Dragon PTN network, and vice versa. The destination IFM must also compensate for
possible jitter and network delays to keep everything synchronized. A packetized TDM
service is called a Circuit Emulation Service (=CES). A maximum of 16 CESs can be configured
per 2-C37.94 module.
2-C37.94 refers to ‘2 C37.94 ports and 2 E1/T1 ports’. This IFM can be used in any IFM slot of
any node. An IFM slot overview can be found in Ref. [3] in Table 1.
The main supported features are:
Packetizing of E1/T1 Framing
LAN function
Services
SAToP (=Structured Agnostic TDM over Packet)
all channels transparently;
CESoPSN (=CES over Packet Switched Network)
customized channel transport;
Hitless Switching / Single Path;
Synchronization
SyncE;
A common example with C37.94, E1 and T1 can be found in the figure below:
