Cisco Support Community
Community Member

All traffic leaving untagged?


I am currently working on my first UCS installation. Current version is  1.43. We are using 6120XP FIs and B200 blades with M81KR VICs. Ethernet  Uplinks are configured to 2 NEXUS 5548UP.

There are two vlans configured so far in all switches and also UCS manager.

I’ve installed 4 Linux hosts and 2 Windows 2008 (all bare metal  installations). 2 VNICs were created on the server profiles and  associated to each one of the VLANS (110 Public , 10 Private) with the  native VLAN option unchecked. The problem i have is that traffic from  ALL hosts is leaving untagged. I can ping the default GW for the public  VLAN , that is connected to one of the 5548 , only when the port is on  VLAN 1. I also reconfigured one of the host’s Public NIC to access VLAN 1  instead of 110 and it is still able to ping the other host in VLAN 110,  which i think confirms that traffic is leaving untagged. Any thoughts  about this ?


Cisco Employee

Re: All traffic leaving untagged?

First, that version is extremely old.  I would suggest considering updating to 2.0 or 2.1 at the least before you go live.  Many enhancements and new features added since 1.4(3) days.

In regards to your question is it possible your GW is sitting in VLAN1 on the 5548's?  That's the only explanation that fits.  I would check the following:

-On the 5548 "show int trunk int Eth x/y" and "show run int Eth x/y" and see which VLANs are configured forwarding on the GW's interface.  Sounds very much like you have a "flat" network - everything using VLAN 1, at least your GW would appear so.

One simple test you can do is create a couple of SVI (Switched Virtual Interfaces) on the 5548, one for VLAN 10, and another for VLAN 110.  Give them IP addresses in their respective subnets.  Then with your UCS Service Profile vNICs configured for VLAN 110, and VLAN 10, see if each can ping the SVI interfaces on the N5K.  If they can reach the N5K fine, your traffic is being tagged correctly and its your GW which is not in the correct VLAN (likely VLAN 1).

Creating SVI's on N5K's:

feature interface-vlan

int vlan 10

  ip address x.x.x.x

  no shut

int vlan 110

  ip address y.y.y.y

  no shut

Ensure the SVI and your Windows/Linux Host IPs are in the same subnet for their VLAN.



Community Member

All traffic leaving untagged?

Thanks for your prompt answer. I'll run the suggested checks tomorrow and will revert back .



CreatePlease to create content