Cisco Nexus 1000V

Hello and welcome back to DCV Cloudtech. In today’s blog, we are going to have a look at Cisco Nexus 1000V, the software switch from Cisco that is poised to replace the hypervisor based switches we usually find in Virtualized environments.

So, what is software based switch or software defined networking. SDN’s are like traditional hardware switches performing layer 2 networking functions except that they don’t run on dedicated switch hardware. They run inside a hypervisor like ESX from VMware or Hyper-V from Microsoft. One of the most common examples of SDN is the Distributed virtual switch from VMware.

The basic function of the DVS switch to provide uniform network configuration across all the virtual machines in a ESX cluster in order to facilitate DRS, VMotion.  Now, DVS works fine and has been doing a great job from the time it came into the market, but there are pitfalls associated with them.

1. DVS is a VMware product. Nothing against VMware, but the networking features of a DVS still has some shortfalls when compared to standard Ethernet switches.
2. ESX administrators usually perform DVS configurations.  Now for simple configurations, its fine, but for configurations requiring network level granularity at the VM level requires a deep knowledge of L2 networking. Sadly, most of the ESX administrators don’t have the knowledge and most of the network administrators find it uncomfortable working on a VMware product.

To overcome these pitfalls, Cisco came up with Nexus 100V. Now N1kv is also a DVS switch and performs all of the functions of a VMware DVS switch with added features that are inherent to traditional L2 switches.  So, what makes it special then?

From the picture, we can see that the N1KV also sits inside the hypervisor, but the network administrator does the configuration of the N1KV. This provides a huge advantage from management point of view as virtual machines can now be managed as though they are physical machines and networking policies can be directly applied to virtual machines.

So, how does the network administrator manage the N1KV? He does it through a special management tool called VSM which is again a virtual supervisor module. Now, hang on, what is now a VSM? Basically, what Cisco is doing is they are replicating what was there at the physical switch level to the virtual level. If we had a look at a Cat 6500 switch, it would have 2 supervisor modules managing the line cards. Similarly, Cisco’s VSM is also a supervisor module for managing the N1KV remote line card.

Now, we can look at the technical details in a later blog, but what makes N1KV a buyable solution?

1. Its Free – yes, N1KV is free to all customers who have VMware enterprise plus license installed but without security. The security portion basically consists of VSG and other features, but for customers who have that separately, the N1KV is absolutely free. The N1KV is charged separately for having the security features configured.
2. Easy to configure for network administrators – since, the N1KV also run nexus O/S which all the administrators are familiar with. It might not offer all the features of a Nexus 5K or 7K, but good enough to replace the existing DVS solution.
3. VM level visibility and the ability to run SPAN and ERSPAN sessions for VM traffic there by helping to identify network congestions appearing at the VM level.

From this, we can see that the N1KV is a very good product to have if the entire environment is a virtualized environment. With support extended for both Hyper V and Zen server, this really puts Cisco well ahead in the virtualized Data Center picture.

In my next blog, we will have a look at how the N1KV works, its configuration requirements and also have a sneak peak into VM-FEX technology. Till next time, see you in the cloud.