How the different subnet IPs will get connectivity through common uplinks ?

[rahul.maheshwari1]

We have 3 nos. of 5108 Chassis with 24 nos. of B200 M4 blade servers connected to 2 nos. of 6248 UP FIs.  Uplink from both FIs are connected to 2 nos. of Cisco N9K switches in vPC mode. There will be large no. of VMs on blades and these VMs will have IPs of different subnets such as 10.20.100.x , 10.20.101.x, 10.20.102.x, and so on.  As per network team, Cisco Nexus network switch ports, where FI uplinks are terminated, are put into some particular VLAN say 110, which belong to IP address range 10.20.108.x.  From Blade servers, I am able to reach 10.20.108.254 gateway of VLAN 110 configured on nexus device. But other vms which are configured with IPs such as 10.20.100.x , 10.20.101.x are unable to ping.  So, what should be the right configuraton in this case ? 

[Wes Austin]

Hello,

If you are talking about inter-vlan routing/communication, this would occur on the upstream switch connected to the UCS FI. The fabric interconnect will switch locally for devices on the same VLAN, but all other traffic will be sent northbound to be routed/switched accordingly.

HTH,

Wes

[rahul.maheshwari1]

We have configured nexus switch's port 1 and 2 in trunk mode where we have connected FI uplinks. Port channels are configured successfully.  There are total 8 vnics created for each blades installed with Win 2k12. And we are utilizing 2 nos. of vnics as of now. vnic 1 and vnic2. On nexus, some vlans have been allowed like 101,102,103 and so on. I need to configure vlan 101 IP address on vnic 1 and vlan 102 ip address for vnic 2.  So, do I need to assign vlans to vnics in UCS also or else traffic will pass through default vlan ? I have tried without assigning any vlan to vnic1 and I am able to reach gateways of all VLAN. But if I am assigning any other subnet IP to that vnic1 except that of Vlan 101, I am not able to reach any gateway. 

I am facing some challenges with respect to VLAN configuration in UCS. Can you refer any guide for nexus ucs connnectivity ? 

[Walter Dey]

see eg.

http://www.cisco.com/c/en/us/support/docs/servers-unified-computing/ucs-2104xp-fabric-extender/110517-vlan-config-ucs.html

and

http://www.cisco.com/c/en/us/support/docs/servers-unified-computing/ucs-manager/116095-configure-ucs-upstream-port-channel-00.html

[shawn.pennell]

If I am reading your post correctly and depending on your environment, the Nexus ports that the FI's connect to need to be trunks.

[Kirk J]

For ports of the 'uplink' type on FIs, trunking is the only mode supported.  For endhost (default) mode, any ports on your north bound switches will need to be mode trunk.  You also will need to make sure those ports/port-channels are configured with 'port fast' for CAT type switches, or 'spanning tree port type edge' for nexus switches,  so that spanning tree events do not impact FI connectivity.

Thanks,

Kirk...