09-06-2014 03:16 AM - edited 03-07-2019 08:39 PM
Hi all ,
we have a network with CORE4507 access 2960x24port+4portSFP
CORE configured to allowed vlan all till access switch SFP interface Gi1/0/27 when i show log to switch i found error below.
\%SW_MATM-4-MACFLAP_NOTIF: Host 4025.c225.d9f0 in vlan 16 is flapping between port Gi1/0/27 and port Gi1/0/12
In access switch port Gi1/0/12 and port Gi1/0/24 is configured as trunk and WAP121 wirelessAP is connected tow SSID,s are configured SSID1=VLAN 10 SSID2=VLAN16
interface GigabitEthernet1/0/12
switchport trunk allowed vlan 10,16
switchport mode trunk
interface GigabitEthernet1/0/24
switchport trunk allowed vlan 10,16
switchport mode trunk
Any Help
Regards
09-06-2014 03:25 AM
Hi,
Please provide config of port Gig1/0/27 and login to device connected to Gig1/0/27 and check from which port you are learning MAC in question. MAC flap shows layer2 loop, by tracing MAC learning on each device we can get some idea same MAC is being learned on two ports.
Regards,
Akash
09-06-2014 03:49 AM
Hello Akash,
Thanks for repley port 1/0/27 is configured as trunk and allowed Vlan All
interface GigabitEthernet1/0/27
switchport mode trunk
this is sh cdp ne
V35#sh cdp neighbors
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone,
D - Remote, C - CVTA, M - Two-port Mac Relay
Device ID Local Intrfce Holdtme Capability Platform Port ID
CORE1 Gig 1/0/27 176 R S I WS-C4507R Gig 1/23
Regards
09-06-2014 05:01 AM
You need to login to CORE1 (4500) and check from which interface you are learning the MAC 4025.c225.d9f0 and why. Is it expected to traffic from the mac to come on 4500. Try to draw a layer2 topology from V35 to device (having mac 4025.c225.d9f0) and check where l2 loop is possible.
-Akash
09-06-2014 03:26 AM
Two links from the 4500 going to 2960X but both links are NOT an Etherchannel?
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide