This is one that's just occurred to me and I have no L3 switches to lab it on. I am planning a large scale VRF-Lite rollout and the following has occurred to me: Are L3 sub-interfaces dot1q tags tied to the VLAN database on a L3 switch in anyway ? Say I have an L2 access port assigned to VLAN 7 along with an associated SVI "interface VLAN 7" with and Ip address of 10.1.7.1/24. Can I then configure a L3 sub-interface with a dot11 tag of 7 and give it an IP address of 10.1.8.1/30 ? If so can I then create another L3 sub-interface on a different physical port and also tag that with 7 and give it an IP address of 10.1.9.1/30? What I suppose I am asking here is are the dot1q tags on L3 sub-interfaces only of local significance to that physical port or is the traffic exiting or arriving on them or even the VLAN allocation tied back to a normal L2 VLAN with the same ID on that switch or even other L3 sub-interfaces with the same dot1q id ? If the VLAN IDs only have local significance on L3 sub-interfaces it would save on using a lot of VLANs up with say 20 VRFs and 20 L3 aggregation switch pairs under the core switches.   ... View more

Hi I have deployed an ACI fabric. Currently its network centric with 1 VLAN = 1 BD = 1 EPG. I have static VLAN pool (1-999) that covers all the VLANs that the servers to be migarated to ACI live on in the legacy datacentre. The pool is associated with a "migartion" physical domain and I have a vPC connecting the fabric to the legacy datacentre. All the EPGs for the migartion VLANs are stically assigned to this vPC with the encap set as the correct external to ACI VLAN. All bridge domains are L2 and the gateway lives outside of ACI currently. I have some test servers that also have some of these EPGs statically extended to them on 802.1q trunks attached to the fabric (I used the same physical domain) and they can talk to each other just fine and can talk to servers on any VLAN outside the fabric. Now we want to deploy some UCS B series servers with VMware integration with ACI and migarte some VMs from the legacy DC into the fabric and this is where I am getting confused.   The documentation says that for VMware integration to use a dynamic VLAN pool. How does that work with migration ? A VM on the legacy network will be on say vlan 12 and when its migrated onto the UCS it will be expecting to still be connected to VLAN 12. How do we control which EPG is mapped to which dynamic VLAN in this case ? When initially setting up the ESXi servers the vSwitch wont be under ACI control as it cant be until ESXi is up and running and has an ACI controlled DVS pushed to it so what goes on with VLAN to PEG mapping here ? On the vPC from the fabric leaves to the UCS fabric interconnects do I extend the same physical domain and VLAN pool as to the DVS ? Also is it possible to reuse VLANs in different physical domains ? For VMware servers and VMs for example we might need only VLANs 100 - 200 and for IBM AIX servers VLANs 100 - 150 can I create two VLAN pools with overlapping VLANs and use them with different physical domains and still have the devices talk to each other ? I am sure I'm missing something very obvious here. Thanks Pat ... View more

Hi I need to support Microsoft NLB in muticast mode on a pair of Nexus 6Ks. I have looked at the example on CCO but that it is for a 7K and on the 6K the command:   layer-2 multicast lookup mac is not available. I saw a another post and a feature request to add this support to the 6K and the feature request seems to indicate it is in 7.x NX-OS for the 6K. I have upgraded to the latest 7.0.2 but the command is still not there. Is it configured in a different way on a 6K or is multicast NLB still not supported ?   Thanks   Pat ... View more

Hi I have a stack of two 3850s connected to a Nexus 7k via a L2 access port. We have found that unless the VLANs match on the 3850 and the Nexus 7K access port you cannot ping between the 3850 and the Nexus 7k (or indeed between hosts connetced to these switches). So 3850 switchport access vlan 12 switchport mode access int vlan 12 ip address 10.1.1.1.2 255.255.255.0   N7K switchport mode access switchport access vlan 22 int vlan 22 ip address 10.1.1.1 255.255.255.0   Ping from 10.1.1.1 to 10.1.1.2 fails.   Move the port and SVI on the 3850 to VLAN 22 and it works ! This is strange as access ports should not be tagging frames so the vlan should be irrelevant (so long as the SVI is on the matching VLAN).   ... View more