Problem Statement: Overlays for Network Virtualization
RFC 7364
Internet Engineering Task Force (IETF) T. Narten, Ed.
Request for Comments: 7364 IBM
Category: Informational E. Gray, Ed.
ISSN: 2070-1721 Ericsson
D. Black
EMC
L. Fang
Microsoft
L. Kreeger
Cisco
M. Napierala
AT&T
October 2014
Problem Statement: Overlays for Network Virtualization
Abstract
This document describes issues associated with providing multi-
tenancy in large data center networks and how these issues may be
addressed using an overlay-based network virtualization approach. A
key multi-tenancy requirement is traffic isolation so that one
tenant's traffic is not visible to any other tenant. Another
requirement is address space isolation so that different tenants can
use the same address space within different virtual networks.
Traffic and address space isolation is achieved by assigning one or
more virtual networks to each tenant, where traffic within a virtual
network can only cross into another virtual network in a controlled
fashion (e.g., via a configured router and/or a security gateway).
Additional functionality is required to provision virtual networks,
associating a virtual machine's network interface(s) with the
appropriate virtual network and maintaining that association as the
virtual machine is activated, migrated, and/or deactivated. Use of
an overlay-based approach enables scalable deployment on large
network infrastructures.
Narten, et al. Informational [Page 1]
RFC 7364 Overlays for Network Virtualization October 2014
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7364.
Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Narten, et al. Informational [Page 2]
RFC 7364 Overlays for Network Virtualization October 2014
Table of Contents
1. Introduction ....................................................4
2. Terminology .....................................................6
3. Problem Areas ...................................................6
3.1. Need for Dynamic Provisioning ..............................6
3.2. Virtual Machine Mobility Limitations .......................7
3.3. Inadequate Forwarding Table Sizes ..........................7
3.4. Need to Decouple Logical and Physical Configuration ........7
3.5. Need for Address Separation between Virtual Networks .......8
3.6. Need for Address Separation between Virtual Networks and ...8
3.7. Optimal Forwarding .........................................9
4. Using Network Overlays to Provide Virtual Networks .............10
4.1. Overview of Network Overlays ..............................10
4.2. Communication between Virtual and Non-virtualized
Networks ..................................................12
4.3. Communication between Virtual Networks ....................12
4.4. Overlay Design Characteristics ............................13
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