cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
1118
Views
0
Helpful
4
Replies

duplicate ACK

MZydorczyk2
Level 1
Level 1

What could be the cause of a duplicate ACK besides mismatched duplex and speed settings?

4 Replies 4

suelange
Level 1
Level 1

dropped packets for one thing...not just mismatched settings...can be caused by excessive traffic, physical errors, bad drivers, bad nics....

where and how are you seeing them?

I am not sure where my boss was seeing them but you can see the dropped packets when you ping. What kind of physical cable problems could there be? Mainly bad cables?

dropped pings can be cause by a lot of different problems, physical line issues only being a small part of them. Check the speed/duplex of the interfaces between the host doing the pinging and the host receiving the ping. Check for errors. Check cpu utilization on routers, swtich and the hosts. Check buffer size and queue size. You could have anything from a router with 100% cpu to a interface queue thats full or even if the end host is over utilized and not responding in time.

GL

Joseph W. Doherty
Hall of Fame
Hall of Fame

Packets delivered out of sequence will also generate dup ACKs.

Getting Started

Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community:

Innovations in Cisco Full Stack Observability - A new webinar from Cisco