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1st packet loss (ICMP) between ws-6509E and cisco7300


I've tried to look everywhere to identify the issue with 1st packet loss, but I have not found any topic or BUG withing Cisco DB.

Brief desc.

Core swtich 6509 directly connected on Gig port to GW router 7300 (MPLS CE) is facing 1st packet loss.

Core switch configured with SVI interface connected through CAT6 cable (measured) leading to router GBIC 1000base-T.

1st packet loss occurs only with initiated traffic, rest of icmp packet are replied and successful. After random time approx. 30-50 seconds, when traffic is initiated again, 1st packet loss occurs.

Static ARP has been set, still issue.

GBIC module changed (brand new), still issue.

Cable changed, still issue.

Patched to new spare ports, still issue.

Traffic inspected via WS, all ICMP request sent successfully, 1st ICMP reply failed.

ICMP send with timeout 30 seconds, still issue.

MAC address table default timer 5mins is ok.

Show ip traffic shows CRC in replays and it's incrementing with every 1st packet loos.

IP CEF is valid and glean for years.

Did anybody has faced the same or similar symptomps ? Please advise where to look and whether this might be a bug on IOS.

P.S. "I've got the same mirrored design on different site and there is no issues whatsoever"



Hall of Fame Super Gold

1st packet loss (ICMP) between ws-6509E and cisco7300

Update IOS and check again.

Community Member

1st packet loss (ICMP) between ws-6509E and cisco7300

It won't such a easy task as it is production devices. But, I was thinking about it in first place.

I will provide an update once this is done.

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