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Enterprise SDN: Moving from box boundaries to software boundaries

November 1, 2012 at 7:10 am PST

Enterprise trends driving SDN and Network Programmability are becoming clearer.  The skyrocketing number of virtual/cloud devices is making human configuration infeasible.  A natural result will be that networks will move from being integrated based on physical box boundaries to being integrated based on software boundaries.  Put another way, traditional box based network integration will be overwhelmed by device proliferation.  Therefore businesses must adopt new approaches to device configuration and control.  This will include a new layer of network software which will instantiate, orchestrate, and dismantle virtual networks.

But what does this really mean?  Read More »

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Evolving Provider L2VPN Services with E-VPN

A team of us at Cisco has been working, together with industry colleagues, on defining and standardizing a new Layer 2 VPN solution known as Ethernet Virtual Private Network or E-VPN. In this post, I will discuss the key requirements that helped shape this solution, and attempt to shed some light on the drivers for the technology and how it enables the evolution of Service Provider L2VPN offerings. Read More »

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Why onePK is Better

This is the first in a series of posts about network based software development for “typical”  enterprise developers, and how onePK can help.

Network based software development is special. The main interfaces are based on CLI interactions and SNMP, not to mention using RADIUS as a RPC mechanism, various forms of XML/HTTP found nowhere else, and additional innovations. For a typical enterprise or script developer these kinds of interfaces are unusual, to say the least. Read More »

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Overlays, Underlays and the New World Order

The networking industry has recently developed a renewed interest in virtual overlays, often wrapped in an “SDN as the controller” context. Amidst the promise, the hope and the hype, the following questions present themselves:

  • What exactly is an overlay?
  • What distinguishes an overlay from a VPN?
  • How decoupled can an overlay be from the underlay network and what are the tradeoffs?
  • What are the advantages of overlays and will they emerge as the new networking world order? Read More »

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EIGRP vs OSPF – Take 2

September 13, 2012 at 8:01 am PST

First a bit of disclosure.  I have worked for Cisco over 15 years, much of that time as the lead developer for EIGRP. I think I understand its strengths and weakness’ very well, and have spent a great deal of energy minimizing them.

I often find comparing protocols similar to the old “tab vs spaces” or “emacs vs vi” wars.  There are valid reasons to choose one over the other and in the grand scheme of things it comes down to a wash; often preference or ‘religion’.  EIGRP seems to victim to this .  I mean where are the “ISIS vs OSPF” debates?  With EIGRP, network engineers that love it – love it. Those that don’t, well they don’t. Arguing its merits often results in an equally long list of “yea but” demerits.

For example, most everyone would agree eigrp is “simple to deploy”, but detractors would argue that simplicity leads to sloppy designs and only though complexity can we force network engineers to “do their job” and design the network properly. Read More »

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