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New Member

Slow network speeds

Just installed a 6509e and a 3560 switch in my LAN. Singlemode fiber is connecting the 2 switches using gbics. When moving data between the switches, transfer speeds get no higher than around 50mbps. Doing a sh int gig 5/1 produces the following. Lot of input errors. I would think possibly a duplex/speed mismatch, but it does not appear that I can configure on the sfp ports. Any help would be greatly appreciated.

GigabitEthernet5/1 is up, line protocol is up (connected)

Hardware is C6k 1000Mb 802.3, address is 0016.4708.9d30 (bia 0016.4708.9d3

MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,

reliability 254/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

Full-duplex, 1000Mb/s, media type is SX

input flow-control is off, output flow-control is off

Clock mode is auto

ARP type: ARPA, ARP Timeout 04:00:00

Last input 00:01:18, output 00:00:45, output hang never

Last clearing of "show interface" counters 01:10:38

Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: fifo

Output queue: 0/40 (size/max)

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 7000 bits/sec, 9 packets/sec

351983 packets input, 237817255 bytes, 0 no buffer

Received 123 broadcasts (91 multicasts)

158 runts, 0 giants, 0 throttles

830 input errors, 0 CRC, 672 frame, 0 overrun, 0 ignored

0 watchdog, 0 multicast, 0 pause input

0 input packets with dribble condition detected

415507 packets output, 438367084 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 PAUSE output

0 output buffer failures, 0 output buffers swapped out

Hall of Fame Super Gold

Re: Slow network speeds

Hi, you have some input errors, although not very many. You should look in having your fiber patch replaced.

New Member

Re: Slow network speeds

I will have the fiber patch tested. Using ethernet backbone speeds were fine and no input errors. On the fiber port, after changing where I was plugged in on the panel, the times were better, but the input errors were still increasing. Link light was flashing green/orange indicating an error. Speeds were better, but would fluctuate.

New Member

Re: Slow network speeds


You said you are using single mode fibre for the link, but the the show interface output states media type is SX - this indicates a multi mode transciever (If SFP/GBIC were single mode , then media type would be LX or LH). You cannot mix these modes unless using fibre mode conditioning patch leads. This may be your problem,

Hope this helps


New Member

Re: Slow network speeds

Thank you. Makes sense. I will check gbic tomorrow.

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