10GE is becoming the new standard in data centers. It’s common knowledge that with virtualization in the datacenter, we are faced with new challenges. However, a few challenges like limited slots for NICs in a node which limits the number of ways the OS can logically connect to your datacenter infrastructure can be mitigated as described in this article. Wouldn’t it be great to virtualize the physical layer of your network?
Virtualizing your 10Gb NIC into multiple logical NICs (vNICs) so that it appears as a separate interface to your hypervisor or the OS and uses a percentage of the available 10Gb bandwidth has been an interesting development. It is to be noted that vNICs can only be implemented on the 10Gb ports and you can carve a maximum of four vNICs for each physical NIC.
How are vNICs implemented in a datacenter?
In IBM PureFlex configurations, vNICs can be implemented through the IBM Flex System Fabric EN4093 10Gb scalable switch and IBM Flex System CN4054 4-port 10Gb Ethernet Adapter or the Embedded 10Gb Virtual Fabric Adapter (Lan on Motherboard)
Both of aforementioned adapters currently support Virtual Fabric in two different modes: Virtual Fabric mode and Switch Independent mode.
In Virtual Fabric mode, the configurations involving bandwidth allotment on the NICs, creating vNIC groups that contain some downlink and uplink ports etc are performed on the switch. Virtual Fabric mode itself has two different modes namely dedicated uplink and shared uplink modes. How many uplink ports you include on the vNIC groups on the switch differentiates between these two modes i.e. one physical/logical uplink for the dedicated and multiple uplinks for the shared mode. Note that the configurations in this mode, can be done in real time without a reload.
In Switch Independent mode, all configurations are done at the adapter level from the node itself. Note that the configurations in this mode, can’t be done in real time and requires a reload.
As a basic example of IBM PureFlex Networking Implementation (NGT51), let’s illustrate what we are trying to achieve:
As an example, with virtual NICs turned on in Lan on Motherboard, your vCenter will view eight different NICs;
And, an example configuration on the IBM Flex System Fabric EN4093 10Gb scalable switch ; where 2.1 to 2.4 and 3.1 to 3.4 are internal pipes to two different nodes on the PureFlex chassis.
