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New Member

6248 connected to 3750 yet ports not configured as trunkport

                   I've setup a 2 5108's with 6248 Fabrics and my ethernet uplinks are going to a 3750x. I'm not proficient with all that comes with switching but I manage to get my systems up and running effectively. After installing my esxi's on the systems I noticed that all of them were getting DHCP addressed from my network yet although I enabled my uplinks and configured them as 1gb I hadn't move the patch cables to the uplink ports on the 3750 configured as Trunk ports. Now in the past this was a show stopper. Am I missing something here. And lastly, I intend to aggregate some links with Port Channeling which is easy enough on the UCS but a note states the upstream switch needs to be configured as LACP.

In short:

1.) Do i need to configure my ports on the 3750 as Trunk dot1q or has something changed and it's auto-sensing

2.) To do the Port Channel does it require Trunk or Switch and is it absolute that I configure LACP on the upstream 3750.



6248 connected to 3750 yet ports not configured as trunkport


As you may know, trunks pass more than one VLAN and Access pass only one VLAN, how many VLANs will you pass through those links? (that will give you the answer)

In regards to LACP, UCS only works with LACP so you need to configured the upstream switch to use LACP instead of mode on or passive.

Rate ALL helpful answers.


New Member

6248 connected to 3750 yet ports not configured as trunkport

I understand Trunking, a little however, when it comes to the UCS fabrics I have never been able to configure the upstream switch with anything other than Trunk Mode where I connect my ethenet uplink ports. Yet using a newer 3750x it is running without trunkports where my uplinks are connected. This is not normal. My test....I moved the patch cables to the configured Trunk Ports on the upstream 3750 and it stopped working, moved them back to the switchports and it started working. Next to this system is another with an earlier model 3750, (sorry I'm missing the specifics) and this will not work with the switctport mode, yet when plugged into the trunk ports of the upstream 3750 it works fine. As for Vlan's I have one other than Vlan 1 which is always the way I've configured these. I've configured about 15 sets of fabrics and only this one is acting this way.

As for the Port Channel configuration thanks. I'm assuming that even in trunk mode I can set LACP.

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