Cisco PIX 506E with high collisions

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- Joe_Cool97
  
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posted
17 years ago

Fri, Jun 30, 2006 2:58 AM

I was hoping someone could help me with a problem on my Pix. I am getting high collisions on my inside and outside interfaces. The ISP is also seeing collisions. The interfaces are set to auto but drop to

10 half duplex. Does anyone have any ideas on where I should start? Here is a sh int (I recently rebooted so the collisions are low, they have gotten into the thousands before):

interface ethernet0 "outside" is up, line protocol is up Hardware is i82559 ethernet, address is 0007.50b6.feef IP address x.x.x.x, subnet mask 255.255.255.248 MTU 1500 bytes, BW 10000 Kbit half duplex 2650 packets input, 762022 bytes, 0 no buffer Received 19 broadcasts, 0 runts, 0 giants 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 2319 packets output, 560824 bytes, 0 underruns 0 output errors, 1 collisions, 0 interface resets 0 babbles, 0 late collisions, 24 deferred 0 lost carrier, 0 no carrier input queue (curr/max blocks): hardware (128/128) software (0/2) output queue (curr/max blocks): hardware (0/4) software (0/1) interface ethernet1 "inside" is up, line protocol is up Hardware is i82559 ethernet, address is 0007.50b6.fef1 IP address y.y.y.y, subnet mask 255.255.255.0 MTU 1500 bytes, BW 10000 Kbit half duplex 3050 packets input, 534606 bytes, 0 no buffer Received 658 broadcasts, 0 runts, 0 giants 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 2659 packets output, 654704 bytes, 0 underruns 0 output errors, 7 collisions, 0 interface resets 0 babbles, 0 late collisions, 16 deferred 0 lost carrier, 0 no carrier input queue (curr/max blocks): hardware (128/128) software (0/4) output queue (curr/max blocks): hardware (0/2) software (0/1)

When the collisions get high the ISP connection drops. Sometimes it comes back on its own.

Anyhelp would be appreciated. Joe

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- anybody43
  
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posted
17 years ago

Fri, Jun 30, 2006 12:46 PM

Collisions are part of Ethernet. Search for threads on comp.dcom.lans.ethernet containing collisions and Seifert for a lot more discussion or read Mr Seifert's book. "The Switch Book: The Complete Guide to LAN Switching Technology (Hardcover)"

So many people now have the mistaken belief that collisions are something bad that even Cisco have MISTAKENLY counted them as errors on some equipment.

cat4000-i5s-mz.122-20.EW.bin FastEthernet5/10 is up, line protocol is up (connected) 1094653 packets input, 201938161 bytes, 0 no buffer Received 44378 broadcasts (0 multicast) 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 56834290 packets output, 4744161523 bytes, 0 underruns 7979 output errors, 7808 collisions, 0 interface resets Collisions INCORRECTLY counted as errors.

0 babbles, 169 late collision, 0 deferred

switch>sh int fa 5/10 count err

Port CrcAlign-Err Dropped-Bad-Pkts Collisions Symbol-Err Fa5/10 0 0 2 0

Port Undersize Oversize Fragments Jabbers Fa5/10 0 0 0 0

Port Single-Col Multi-Col Late-Col Excess-Col Fa5/10 6555 1253 169 0

Port Deferred-Col False-Car Carri-Sen Sequence-Err Fa5/10 0 0 0 0

In this example there is or has been a duplex mismatch since I have got Late-Collisions.

This is NOTHING to do with collisions.

Use the traffic counters to figure out if the link is busy or not.

What you don't want are:- Late-Collisions - nowadays usually indcative of a duplex mismatch Excessive-Collisions - indicative of overloaded network - eliminate Late colls first if any then re-visit CRC errors - bad link. - maybe can happen in HD - forget. - maybe if crc = runts it is ok,

"Excessive-collisions" are a different type of collision and are not just too many ordinary collisions.

Either record the traffic with snmp getif.exe is a very simple way to get started for free or you can change the load-interval on the interface to 30 seconds if you don't want to do that.