No relevant resource is found in the selected language.

This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies. Read our privacy policy>

Reminder

To have a better experience, please upgrade your IE browser.

upgrade

FAQ-why the length of ping packet is difference between input statistic and output statistic in ME60

Publication Date:  2012-07-27 Views:  40 Downloads:  0
Issue Description
Q:
the customer send the icmp packets through ME60, then they check the statistic of ME60 and find out the input bytes is more than output bytes for 4 bytes per packet. why ?
Alarm Information
1. Case 1 physical interface 
the packet length is (32(payload)+8(icmp)+20(ip)+14(eth)+8(pppoe)) x 10
 a. Sub session 
Input bytes:            860  
Output bytes:         820 
2. Case 2 sub-interface 
the packet length is (32(payload)+8(icmp)+20(ip)+14(eth)+4(Vlan tag)+8(pppoe)) x 10
a. Sub session 
Input bytes:            900
Output bytes:         860 
Handling Process
A:
the 4 bytes is the length for CRC code in those 2 cases.
in case 1, when the icmp packet arrived, it has the CRC code. so input bytes is 86 bytes, then ME60 need cut of the CRC to get the payload, and now ,the length is 82 bytes, 
when the ME60 transfer the packet, the packet will be calculated in output direction,and in that time ,the packet is till 82 bytes, so the output bytes is 82 bytes,
at last ,the packet is added a new CRC code in PIC card before it is sent out. 
Root Cause
Null
Suggestions
 Null

END