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High latency issue in cisco 2960X switch

Dear Sir,

All of our Lan pcs are connected to 2960X L2 Switch . 2960X Switch is connected to 1921 router. From two days I am getting high latency when trying to ping the switch or the gateway router. Will you please suggest how to troubleshoot the issue.

Thanks and regards

KS Ghosh

3 Replies 3

Joseph W. Doherty
Hall of Fame
Hall of Fame

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Do you know that pinging either a Cisco router or switch often isn't an accurate test of latency?  The reason being, both devices treat dealing with pings requests, to themselves, as a low priority item.  Some Cisco devices support a speical responder that will allow for much more precise latency tests, but your source source would need to know to use it, and the receiver would also need to be configured to use it.

Assuming that the foregoing isn't the issue, you might look for congested interfaces.  Such will queue packets including ping requests/replies, and for those, or other packets, latency will increase due to queuing delay.

Sir,

Thanks a lot for you reply. I need some more help.

1. Will you please share knowledge regarding  latency check in Cisco L2 LAN .

2nd: One of my Cisco Switch is connected on Port Gi1/0/20 with D-Link HUB. Now I am getting thse message in syslog server. Will you please specify how to solve the issue please ?

Nov 16 10:42:57 192.168.1.250 25232: Nov 25 03:36:33.817: %SW_MATM-4-MACFLAP_NOTIF: Host d8cb.8a62.71dc in vlan 1 is flapping between port Gi1/0/20 and port Gi1/0/3
Nov 16 10:43:04 192.168.1.250 25233: Nov 25 03:36:40.252: %SW_MATM-4-MACFLAP_NOTIF: Host d8cb.8a62.71dc in vlan 1 is flapping between port Gi1/0/3 and port Gi1/0/20
Nov 16 10:43:13 192.168.1.250 25235: Nov 25 03:36:48.420: %SW_MATM-4-MACFLAP_NOTIF: Host d8cb.8a62.71dc in vlan 1 is flapping between port Gi1/0/20 and port Gi1/0/3
Nov 16 10:43:15 192.168.1.250 25236: Nov 25 03:36:50.629: %SW_MATM-4-MACFLAP_NOTIF: Host d8cb.8a62.71db in vlan 1 is flapping between port Gi1/0/20 and port Gi1/0/6
Nov 16 10:43:17 192.168.1.250 25237: Nov 25 03:36:52.841: %SW_MATM-4-MACFLAP_NOTIF: Host d8cb.8a62.71dc in vlan 1 is flapping between port Gi1/0/20 and port Gi1/0/3
Nov 16 10:43:17 192.168.1.250 25238: Nov 25 03:36:53.575: %SW_MATM-4-MACFLAP_NOTIF: Host d8cb.8a62.71dc in vlan 1 is flapping between port Gi1/0/20 and port Gi1/0/3
Nov 16 10:43:21 192.168.1.250 25240: Nov 25 03:36:56.609: %SW_MATM-4-MACFLAP_NOTIF: Host d8cb.8a62.71dc in vlan 1 is flapping between port Gi1/0/20 and port Gi1/0/3
Nov 16 10:43:24 192.168.1.250 25241: Nov 25 03:36:59.779: %SW_MATM-4-MACFLAP_NOTIF: Host d8cb.8a62.71dc in vlan 1 is flapping between port Gi1/0/20 and port Gi1/0/3
Nov 16 10:43:24 192.168.1.250 25242: Nov 25 03:37:00.636: %SW_MATM-4-MACFLAP_NOTIF: Host d8cb.8a41.a6fd in vlan 1 is flapping between port Gi1/0/20 and port Gi1/0/23
Nov 16 10:43:34 192.168.1.250 25243: Nov 25 03:37:09.895: %SW_MATM-4-MACFLAP_NOTIF: Host d8cb.8a62.71dc in vlan 1 is flapping between port Gi1/0/20 and port Gi1/0/3
Nov 16 10:43:37 192.168.1.250 25244: Nov 25 03:37:12.922: %SW_MATM-4-MACFLAP_NOTIF: Host d8cb.8a62.71db in vlan 1 is flapping between port Gi1/0/20 and port Gi1/0/6 

Raja_D
Level 1
Level 1

Dear Kripasindhu, 

please check in the arp table of the switch using command "show ip arp" and verify if you are able to get all the pc entries in the arp table or not. Also ping those ip's from the switch directly to find if you are getting any packet drops or not. 

Please do check the uplink interfaces connection between router and switch and find if there are any crc errors gettting generated on the uplink ports or not. 

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