Cisco swicthport statistics

While diagnosing your network because of performance issues, if you do determine that the network is not meeting technical expectations, you should isolate the source of the problem and diagnose the problem on that device. Whireshark is a cool tool to find out the root cause of a network performance issue. So, if i were to answer to the following question : which tool among many comes into your mind to pinpoint the root cause of a network performance issues ? I would have given the following answer : WIRESHARK.


After diagnosis, if it is a Cisco switch causing problem, isolate it and focus your diagnosis effort in the following area of the switch :

• ports
• forwarding logic
• backplane
• control plane

Let's us see what information we can gather when troubleshooting ports using the following command : #show interface counters errors   

• ALIGN-ERR  : layer  1  issue,  such  as  cabling   or  port  (SWITCHPORT  or  NIC)
• FCS-ERR : often  layer  1  issue  but  it  also  occurs  when   there  is  a  duplex  mismatch
• XMIT-ERR  :   speed  mismatch
• RCV-ERR :  duplex  mismatch
• SINGLE-COL :  duplex  mismatch
• MULTI-COL  :  duplex  mismatch
• LATE-COL  :  cable  too  long,   duplex  mismatch
• EXCESS-COL  :   duplex  mismatch,  too  many  devices  on  a  segment
• RUNTS  :  duplex  mismatch  or  layer  1  issue
• GIANTS  :   problem  with  NIC

Ofcourse before jumping into your routers or switches or cables or NICs, you need first to determine that your router or switch is the root cause of your network performance issues and Wireshark to a fantastic  free tool that you can use to spot the root of your network performance issues.
>> here is our contacts infos, if you wish to participate in our Wireshark classes
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