Tip of the Day: Network Abstraction Demystified

Today’s (Networking) Tip…

Network Abstraction Demystified

Yesterday's tip talked about the abstraction of the network overlay from the network underlay. Easy enough to say, but how is this actually done?

Relocation of Traffic Shaping Policies

Abstraction is achieved by taking the policy edge of the network; that is to say, the configurations and rules that dictate traffic flow, and moving them away from the physical switches and onto the software-based virtual switches running on hosts.

This is where the Software part of Software Defined Networking comes from.


A feature rich virtual switch is needed to support the variety of policies required in the typical enterprise network, which can include dynamic policies which make real-time forwarding decisions.

QoS Policies

To define customer specific bandwidth caps, or guarantee a minimum SLA.

Security Policies

ACLs, DHCP Guard to prevent against rogue DHCP server, Router Guard to prevent malicious redirects, and so on.

Tenant Isolation Policies

VLANs, PvLANS, as well as modern encapsulation methods used to provide virtual network isolation; NVGRE, VxLAN,

Service Policies

Hardware offload for certain protocols or network services might also be a concern.

The Hyper-V Extensible Virtual Switch provides the capability for the software implementation of network functions including conditional forwarding, flow control, distributed firewalls, and other network services.

Extensibility also allows the experience to be customized beyond the inbox environment. For example, an enterprise can maintain a certain consistency among their existing infrastructure with plug-ins like the Cisco Nexus 1000V Series Switch.


A solution of this sort is only good it can be automated in some way, which is where System Center Virtual Machine Manager comes in.

Virtual Machine Manager can be used to deploy and manage the software-defined datacenter from the datacenter fabric (physical storage, network, and host resources) to virtual machines and clouds, to the deployment and management of applications and services running on the virtual machines.

But How is This Even Possible?

Orchestration using Standardized Interfaces

As mentioned in yesterday's tip, Orchestration describes the coordination of management, control, and configuration of the network fabric. Mechanisms are dependent upon industry standard protocols and interfaces, support of which is a key factor to determining interoperability between diverse platforms.

And there are few to choose from….

Software Defined Network is all about interoperability!!!

Microsoft uses the industry management standard OMI <http://blogs.technet.com/b/windowsserver/archive/2012/06/28/open-management-infrastructure.aspx> for its SDN implementation. An open sourced version of WMI; OMI is at the same time a management schema and a protocol. Other standards include OVSDB <http://www.rfc-editor.org/rfc/rfc7047.txt> , and OpenFlow <https://www.opennetworking.org/sdn-resources/openflow> , which can be used for fine-grained flow control, and Cisco’s OpFlex <http://www.cisco.com/c/en/us/solutions/collateral/data-center-virtualization/application-centric-infrastructure/white-paper-c11-731302.html> .

Other Organizations and Consortiums

ONF Open Networking Foundation <https://www.opennetworking.org/>

Open Daylight <http://www.opendaylight.org/>

Open Compute Consortium <http://www.opencompute.org/>

IETF <http://www.ietf.org/>

DMTF <http://www.dmtf.org/>

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