Re: [nvrg-bof] What is Network Virtualization?

[Joe Touch <touch at ISI.EDU>]

Based on exchanges with a few people on the list, I'll revisit my
initial proposal.

> Some acid tests for a definition:
>     - it should support VPN, PPVPN, and overlays as VNs
>     - it should not define the native Internet as a VN
>         i.e., it must distinguish layering from
>         "overlayering"

Additional notes:
       - network virtualization describes the process of
       creating virtual networks, i.e.,
		NV is the process
		VNs are the artifact

I define NV and VNs via the artifact created, because NV is then most
generally defined:
	NV is *any* process or mechanism that creates (enables the
	creation) of VNs

A _VN_ is a network composed of virtual links, virtual hosts, and
virtual routers. Virtualization of links, hosts, and routers is
accomplished by adding a layer of indirection in the names and/or
addresses associated with each. A VL encodes this indirection sufficient
for use by VHs and VRs; VHs and VRs uses this indirection information to
associate with a VL. Additionally, a VH is a network node that adds or
removes indirection information, and is associated with at least one VL
in a given VN. A VR is a network node that does not add or remove
indirection information, and is associated with at least two VLs in a
given VN.

The rest, I beleive, remains a reasonable summary of the capabilities of
VNs:

> ---
>
> Virtual networks have three primary uses:
>     - protection
>         allow new services/protocols to be deployed on a subset
>             e.g., testbeds, incremental deployment
>         keep experiments from leaking out
>             e.g., testbeds
>         keep others' uses from affecting a given use
>             e.g., emergency services, guaranteed capacity,
>             privacy/authentication
>     - concurrency
>         shared use of common infrastructure
>     - abstraction
>         simplify the topology (e.g., LISP/NERD)
>         support application-specific topology (e.g., P2P)

I have not listed mechanisms that support VNs, i.e., NV mechanisms yet.
These might be summarized as:

NV mechanisms:

	- partitioning (as in Clonable Stacks in hosts/routers, and VPN
	IDs, VLAN IDs, and tunneling in links, etc.)

	- aggregation (channel bonding in links, NAT-like services
	at the edge of server farms and cluster computers, etc.)

	- combinations of the above

Joe

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