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New Member

Span Port - Packets not being received by dest port

My SPAN port, 4/47, doesn't seem to be receiving any of the packets that are being received by port 4/48 (note input packets in the show commands below.) What am I doing wrong?

DO-MDF-CAT6509#sh mon sess 1

Session 1

---------

Type : Local Session

Source Ports :

RX Only : Fa4/48

Destination Ports : Fa4/47

DO-MDF-CAT6509#sh int fa 4/48

FastEthernet4/48 is up, line protocol is up (connected)

Hardware is C6k 100Mb 802.3, address is 0003.6c2a.06ff (bia 0003.6c2a.06ff)

MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

reliability 255/255, txload 1/255, rxload 11/255

Encapsulation ARPA, loopback not set

Full-duplex, 100Mb/s

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

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

Last input never, output 00:00:27, output hang never

Last clearing of "show interface" counters 22:01:55

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 4508000 bits/sec, 459 packets/sec

5 minute output rate 765000 bits/sec, 320 packets/sec

8566485 packets input, 7895865618 bytes, 0 no buffer

Received 64761 broadcasts, 0 runts, 0 giants, 0 throttles

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

0 input packets with dribble condition detected

7862325 packets output, 4134332929 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

DO-MDF-CAT6509#sh int fa 4/47

FastEthernet4/47 is up, line protocol is down (monitoring)

Hardware is C6k 100Mb 802.3, address is 0003.6c2a.06fe (bia 0003.6c2a.06fe)

MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

reliability 255/255, txload 11/255, rxload 1/255

Encapsulation ARPA, loopback not set

Full-duplex, 100Mb/s

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

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

Last input never, output 2w1d, output hang never

Last clearing of "show interface" counters 22:02:11

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 4552000 bits/sec, 463 packets/sec

0 packets input, 0 bytes, 0 no buffer

Received 0 broadcasts, 0 runts, 0 giants, 0 throttles

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

0 input packets with dribble condition detected

8573761 packets output, 7904194606 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

6 REPLIES
Silver

Re: Span Port - Packets not being received by dest port

Show int fa 4/47 shows that Line is down which means clock rate may not be configured proper;y on this LAN segment.Layer 2 Encapsulation may also mismatch.

Re: Span Port - Packets not being received by dest port

Carlos:

Although I have SPAN setup on a different platform than the original poster, the status on my device is the same, and I have no issues with SPAN.

c2950#sh int fa0/1

FastEthernet0/1 is up, line protocol is down (monitoring)

DO-MDF-CAT6509#sh int fa 4/47

FastEthernet4/47 is up, line protocol is down (monitoring)

New Member

Re: Span Port - Packets not being received by dest port

It looks to me like your span port is receiving traffic just fine. You are spanning the RX only traffic from fa4/48 to span port fa4/47. If you look at the input rate on fa4/48 (4508000) it is very close to the output rate on your span port fa4/47 (4552000). The difference is because the ports are on two different five-minute average cycles.

Hope this helps.

-rb

Re: Span Port - Packets not being received by dest port

Chris:

Ron's observation seems valid.

Are you drawing this conclusion because of a mis-configured sniffer (non-promiscuous mode, capture or display filters in use)?

New Member

Re: Span Port - Packets not being received by dest port

What sniffer software are you using. If snifferpro make sure that someone did not change the default info while setting up a trace. Make sure that you can run an open trace with no source or destination IP set up in the filter

Re: Span Port - Packets not being received by dest port

SPAN destination ports are down by design, so don't worry about that.

http://www.cisco.com/en/US/products/hw/switches/ps708/products_tech_note09186a008015c612.shtml#charac_dest

"The state of the destination port is up/down by design. The interface shows the port in this state in order to make it evident that the port is currently not usable as a production port."

Try to use another sniffer, wireshark (a continutation of Ethereal) is nice and free.

Regards

Farrukh

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