• 12/20/2013
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Cisco's SDN Strategy: 4 Critical Questions

Networking customers are digging into the details of Cisco's new software-defined networking strategy, but these big-picture questions also deserve consideration.

Cisco recently announced its new software-defined networking strategy, Cisco Application Centric Infrastructure (ACI). Last week, I wrote about some of the drawbacks of the platform, including its complexity and Cisco's history of software development. Here I outline some other questions customers should ask themselves before venturing into Cisco ACI.

How does ACI compare with other platforms?

All the signs show that Cisco is rallying behind ACI as its flagship SDN product. But we must remember that Cisco also has Dynamic Fabric Automation, the OpenFlow-based Extensible Network Controller, and the Cisco ONE strategy for third-party software integration. At the same time, VMware NSX, Nuage Networks, Midokura, and Big Switch, to name a few, also have products that compete directly -- many offering similar benefits for lower costs.

When discussing Cisco ACI with anyone, the most common question I hear is, "How does it compare to VMware NSX?" It's a fair question, but one that should never be asked. Cisco owns 70% or more of the networking market, dominates network standards bodies, and has a proven history of customer satisfaction. Yet everyone sees VMware NSX as an obvious competitor. Last year, VMware was not a networking company; this year it competes with Cisco. Ouch.

Cisco will need to convince customers that the ACI strategy of integrated hardware and software is the right choice. The VMware NSX story of software independence has real power and will make sense to a large audience. Importantly, NSX has been deployed for more than four years in large companies, and the new version is available today.

Is Cisco SDN really open?

Another issue is the level of Cisco's commitment to open standards.

Read the rest of this article on Network Computing.


SDN !!!

ACI is believed to  provide many of the same provisioning and virtualization features ,but hardware is the foundation of the technology, is hardware the answer ? I was reading across some blog and found a very relevant point, i.e. Application is getting good hype for scaling network if this is so important then how come we have been using MPLS.

Re: SDN !!!

Virsingh, do you think you could find the link to that blog? I don't quite understand the comparison between MPLS and using SDN to scale applications on the network. I thought the use of MPLS has been decreasing in favor of Internet-based networks.

Re: SDN !!!

The only comparison here is that they both imply to network, my only point here was that we have been emphasizing on application based network but on other hand MPLS which was not application based ruled out perfectly and now running smoothly.

Re: SDN !!!

Well, and arguably MPLS was (or could be) software defined, through MPLS-TE providing different CoS to different traffic streams, and largely taking the decision making process out of the hands of the underlying network equipment and treating P routers as "dumb" switches for MPLS packets, while the intelligence was applied at the edge through policies defined either manually or, for many services providers, by way of automated provisioning (including re-routing and backup paths). Look at Cisco's ACI for comparison - using VXLAN to tunnel traffic across the ACI "backbone"; the intelligent decision is made at the edge (ingress) and the rest is just dumb switching. I see strong corelations between some aspects of SDN, at least, and MPLS. At least, that is, where you control the entire end-to-end flow (a problem with many SDN solutions right now).


Greg Ferro wrote about something similar recently --



Re: SDN !!!

MPLS has, and continues, to be a good technology but it does not have the capability to be managed by software remotely. MPLS is intended to be an autonomous and self-configuring system through the use of LDP and BGP. 

SDN really focuses on how we can impact the end to end data path. We need to change it daily or hourly. We need to add and delete configuration without risk. These are not things that MPLS/LDP/BGP can do today. 

Another issues is that MPLS depends on the capacity of the hardware to handle MPLS labels in memory. There is strictly finite TCAM capacity that limits the MPLS to relatively small number of paths. SDN works best with micro-flow management instead of macro-flow management of MPLS. 

The first phase of SDN will be in the data centre where we can control the entire system but the next generation will be in the WAN and SP Core. It will take a few years for the technologies to prove themselves but it will bring many new capabilties.