a sh int serial x will show how much the line is being utilized. the load is calulated by default a five minute average , you can change this nt using the 'load-interval xx' command , In order to calculate the load properly you must change the bandwidth to the size if your pipe. ' bandwidth 64' will change it to a DS0, be careful with this it could efffect routing , Eigrp uses bandwidth for routing metrics.
Serial3/0 is up, line protocol is up
Hardware is M1T-T3+ pa
MTU 4470 bytes, BW 44000 Kbit, DLY 200 usec,
reliability 255/255, txload 5/255, rxload 1/255
Encapsulation HDLC, crc 16, loopback not set
Keepalive set (10 sec)
Restart-Delay is 0 secs
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters 1d04h
Input queue: 1/75/0/0 (size/max/drops/flushes); Total output drops: 339
Queueing strategy: fifo
Output queue :0/40 (size/max)
30 second input rate 1000 bits/sec, 2 packets/sec
30 second output rate 994000 bits/sec, 128 packets/sec
81324 packets input, 10707022 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 2 giants, 0 throttles
0 parity
1158 input errors, 1107 CRC, 0 frame, 40 overrun, 6 ignored, 11 abort
10542322 packets output, 3862034036 bytes, 0 underruns
0 output errors, 0 applique, 0 interface resets
0 output buffer failures, 0 output buffers swapped out
14 carrier transitions
rxLOS inactive, rxLOF inactive, rxAIS inactive
txAIS inactive, rxRAI inactive,