сейчас сделал эксперимент.
отключил всю сеть на другом конце - воткнул ноут - iperf погоняли.
вот результатc5350#sh int fa0/0
FastEthernet0/0 is up, line protocol is up
Hardware is Fast Ethernet, address is 000b.5fda.0cba (bia 000b.5fda.0cba)
Description: *** Center NET ***
Internet address is *******/27
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
reliability 251/255, txload 1/255, rxload 7/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 100Mb/s, 100BaseTX/FX
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters 00:03:22
Input queue: 0/4096/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/4096 (size/max)
5 minute input rate 3039000 bits/sec, 365 packets/sec
5 minute output rate 185000 bits/sec, 255 packets/sec
94523 packets input, 109466450 bytes
Received 1034 broadcasts, 0 runts, 0 giants, 0 throttles
2656 input errors, 2656 CRC, 1301 frame, 0 overrun, 0 ignored
0 watchdog
0 input packets with dribble condition detected
65763 packets output, 4570288 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out
c5350#