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Setting up a LAG with LACP between 3750-X and SG300-10


I am using a stacked pair of 3750-X switches as the core for a network, and there is one location where I need to hook up some devices where I would like to place a local SG300-10 and use a 2 port LAG between the SG300-10.   When I look at status of the LAG (Etherchannel) on the 3750-X it shows as being up.   When I look at the status on the SG-300 it appears to be up.   When I unplug and plug the ethernet cable I see the VLANs on the LAG go up and down from the SG300 log.

Log IndexLog TimeSeverityDescription
21474834532013-Oct-31 19:11:04Informational%AAA-I-CONNECT: New http connection for user cisco, source destination ACCEPTED     
21474834542013-Oct-31 19:07:23Informational%AAA-I-DISCONNECT: http connection for user cisco, source destination TERMINATED     
21474834552013-Oct-31 18:57:08Informational%LINK-I-Up:  Vlan 3     
21474834562013-Oct-31 18:57:08Informational%LINK-I-Up:  Po1     
21474834572013-Oct-31 18:57:08Informational%TRUNK-I-PORTADDED: Port gi9 added to Po1     
21474834582013-Oct-31 18:57:05Informational%LINK-I-Up:  gi9     
21474834592013-Oct-31 18:56:30Warning%STP-W-PORTSTATUS: gi1: STP status Forwarding     
21474834602013-Oct-31 18:56:26Informational%LINK-I-Up:  Vlan 2     
21474834612013-Oct-31 18:56:26Informational%LINK-I-Up:  gi1     
21474834622013-Oct-31 18:54:53Warning%LINK-W-Down:  Vlan 3     
21474834632013-Oct-31 18:54:53Warning%LINK-W-Down:  Vlan 2     
21474834642013-Oct-31 18:54:53Warning%LINK-W-Down:  Po1     
21474834652013-Oct-31 18:54:53Warning%LINK-W-Down:  gi9     
21474834662013-Oct-31 18:54:53Warning%TRUNK-W-PORTREMOVED: Port gi9 removed from Po1     

I have set a couple of ports on the SG-300 to be untagged on the the VLANS and I do not get IP addresses assigned via DHCP, I plug in something statically addressed with that VLAN, and I cannot reach it.   I also cannot reach the admin web pages for the switch via the trunked interface.  The same configuration on the 3750-X works with the Gigabit port on Catalyst Express 520 so I think the 3750-X is configured properly.

Config Info from the SG300

LAG Config Info

LAG Config 1.PNG

LAG Config 2.PNG

LAG Config 3.PNG

VLAN Config Info

VLAN Config 1.PNG
VLAN Config 2.PNG

VLAN Config 3.PNG

Any thoughts on where I might have gone wrong would be greatly appreciated.



1 Reply 1

Yordi Mahieu


I have a Stack of catalys 2960X with 31 sg300 series switches, with 15 diffrend LACP of 2 links.

in this LACP i have about 20 Vlans .

in the screen shot of the LAG i always use TRUNK as VLAN mode !

Make sure at both sides the "untaged" vlans is de same one .

SG300 do not support de cisco prop. protocol. so make sure u use LACP on the other side !



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