Metrodata ATM CBR DSU, Руководство пользователя

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E3 UNI PORT CONFIGURATION
91 76-02-031E
13 E3 UNI PORT CONFIGURATION
13. 1 E3 Physical interface
The signal is transmitted on 75 Ohm RG59 unbalanced coax terminated with BNC
connectors. HDB3 line coding is employed, per G.703 at 34
⋅
368 Mbit/s.
13. 2 E3 Framing
Each frame is composed of 7 bytes of overhead and 530 bytes of payload. The frame rate
is 8 KHz per G.832.
13. 3 E3 PLCP layer
No PLCP is employed because alignment exists between the E3 frames and the ATM cells
carried in the payload.
13. 4 E3 ATM layer
The payload carries 10 ATM cells per E3 frame, giving a cell rate of 80,000 cells per second.
13. 5 E3 WAN Set-up
The E3 port parameters are set by selecting the path:
MAIN SET-UP / WAN PORT SET-UP / E3 PORT
Figure 13.1 E3 set-up
13 . 5. 1 Framing
E3 FRAMING is fixed as G.804.
13 . 5. 2 Line coding
LINE CODING is fixed with a value of HDB3 (High-Density Binary 3).
13 . 5. 3 Timing
TIMING is used to select the clocking mode of the E3 port. Modes are as follows:
Figure 13.2 E3 timing
E3 PORT
Framing G.804
Line coding HDB3
Timing Internal
AIS forwarding Never
RAI forwarding Enabled
Mode Description
Loop E3 TX timed from E3 RX
Internal E3 TX timed from internal oscillator