Quantity is how many containers you have. The result is how many tributaries fit, the path, and the leftover line rate. The choices stay in the URL, so you can share them.

Result: standard mapping

How many E1s are in a STM-4?

A STM-4 carries 252 E1s, per ITU-T G.707.

252

E1s in a STM-4

Working

STM-4 → 4 × STM-1 → 63 × E1

4 × STM-1 in each STM-4 ITU-T G.7074 × STM-1.
63 × E1 in each STM-1 ITU-T G.70763 VC-12 tributaries: 3 TUG-3 × 7 TUG-2 × 3 TU-12.

4 STM-1s
4 × 63 = 252 E1s

Leftover capacity

105.984 Mbit/s of each STM-4 line rate (622.080 Mbit/s) sits outside 252 × 2.048 Mbit/s of E1 line rate (516.096 Mbit/s). That remainder is overhead, fixed stuff or justification. It is not another whole tributary.

By bit rate only

Dividing the line rates gives 303.75, which floors to 303 E1s by bit rate only. The standard mapping is 252. Use the mapping.

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