Re: [vnrg] way forward on VNRG definitions

[Martin Röhricht <[e-mail]>]

Dear Joe,

On 08.06.2010 18:57 Joe Touch wrote:
> As a starting point, we would like to have everyone on the list answer the
> following questions. We would prefer short text rather than full paragraphs
> extracted from any I-D or other document.
> -----------------------------------------------------
>
> Starting questions:
>
> 1. how do you define VNs?

A VN is a network that appears to its users as an ordinary network by
providing ordinary interfaces and services but which is actually
decoupled from the physical substrate.

> 	1.a. what are the key components?

Virtual nodes, virtual links, management entities

> 	1.b. what is the relationship between these components?

An arbitrary number of virtual links may be spanned between an arbitrary
number of virtual nodes.  A physical node may be equipped with multiple
virtual nodes.  Virtual links are controlled by management entities
residing on physical nodes and acting as mediators between pyhsical and
virtual nodes.

> 	1.c. what is the characteristic behavior/capability of the
> 	resulting system?

The resulting virtual network provides its users the illusion of using a
dedicated (physical) network with a set of guaranteed resources.  It
should provide its services isolated from other virtual or physical
networks that actually run on the same hardware.  Network management
operations should be performed transparent for the network's users, e.g.
by migrating nodes or links in the physical substrate.

> 2. what are VNs used for?

VNs may be used to provide a dedicated network for its users which
operates isolated from any other network traffic.  They may be used to
bring out completely new network architectures and protocols.  They may
be used to optimize resource utilization either via aggregating or via
distributing resources used for a virtual network.

> 3. what are they key challenges?
>
> for each challenge:
> 	- define the challenge
> 	- explain why it is hard
> 	- provide some references to those working on solutions

- Instantiation of virtual nodes and virtual links.  How can we a
 priori determine whether a virtual node exists or is actively running?
- Inter-domain-wide operation across multiple administrative domains.
 Comparable to the issues in QoS research we may be able to easily
 provide dedicated services to users within our domain, but providing
 these services inter-domain-wide may have some technical or business
 constraints.
- Dynamic and on-demand instantiation of virtual networks.  Instead of
 using a manual or semi-manual (e.g. script-based) configuration of
 virtual networks, it may be desirable to use signaling protocols for a
 dynamic and on-demand management of virtual networks.
- Network topologies. Talking about virtual networks, we may wish to
 not only control some virtual nodes and virtual links, but also create
 virtual network topologies, such as full-meshed networks, rings,
 trees, etc.
- Attachment of end-users---are they part of the virtual network? How
 do we cope with the mobility of end-users, again inter-domain-wide?
- Aggregation---to what level can we aggregate traffic by still
 preserving isolation and by not losing flexibility to migrate virtual
 nodes and virtual links to another location?
- Security---how can security be achieved?  Is it an integrated part of
the virtual network architecture and transparent to its users?
- AAA---using virtual network resources breaks down to actually using
 physical resources of one or more network operators.  How do we
 provide authentication, authorization, and accountability?  How do we
 provide these AAA services inter-domain-wide?
- Are Quality-of-Service guarantees an inherent requirement for virtual
 networks? If yes, to what extent?
- Providing the users the opportunity to create completely new network
 architectures and protocols inside their virtual networks---how do we
 cope with interoperability?  Or do we run the risk of creating an
 »inverse Internet«?


That's it for now.

Martin