VxLAN Router Alert Option
draft-singh-nvo3-vxlan-router-alert-00

Abstract

This proposal describes a new option to achieve a mechanism which alerts VxLAN terminating VTEP to more closely examine the contents of the packet encapsulated under VxLAN header. This option is useful for case(s) where a given frame encapsulated within a given VXLAN segment responsible for carrying data between two different End Systems contains some control information (e.g OAM information) that may require special handling/processing by terminating VTEP.

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Table of Contents

• 1. Introduction
• 2. Terminology
• 3. Approach
• 3.1. Originating VTEP Procedure
• 3.2. Terminating VTEP Procedure
• 4. Management Considerations
• 5. Security Considerations
• 6. Acknowledgements
• 7. IANA Considerations
• 8. References
• 8.1. Normative References
• 8.2. Informative References
• Authors' Addresses

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC2119 [RFC2119].

When used in lower case, these words convey their typical use in common language, and are not to be interpreted as described in RFC2119 [RFC2119].

1. Introduction

VXLAN [I-D.draft-mahalingam-dutt-dcops-vxlan]is a tunneling mechanism to overlay Layer 2 networks on top of Layer 3 networks. In most cases the end point of the tunnel (VTEP) is intended to be at the edge of the network, typically connecting an access switch to an IP transport network. The access switch could be a physical or a virtual switch located within the hypervisor on the server which is connected to End System which is a VM.

VXLAN segment encapsulates End System data at Originating VTEP and carries it over L3 network to the Terminating VTEP, where VXLAN header is interpreted, removed and data is passed on to the End System.

There could be some scenarios like for case of OAM, where the network element at originating VTEP needs to encapsulate some control information for a given VXLAN segment, and this control information needs to be analyzed and processed at the terminating VTEP for that VXLAN segment.

This document defines a mechanism whereby Originating VTEP can add additional information to the VXLAN header, based upon which the Terminating VTEP can decide to analyze the payload under VXLAN packet, rather then forwarding it to the destination End System.

2. Terminology

Terminology used in this document:

VXLAN: Virtual eXtensible Local Area Network.

VTEP: VXLAN Tunnel End Point.

VM: Virtual Machine.

End System: Could be VM etc. - System whose data is expected to go over VXLAN Segment.

OAM: Operations, Administration, and Maintenance

Other terminologies are as defined in [I-D.draft-mahalingam-dutt-dcops-vxlan].

3. Approach

If the Originating VTEP decides to generate control informtaion, which needs to go over a given VXLAN segment and if the Terminating VTEP needs to analyze and process it, then following procedures have to be followed at Originating and Terminating VTEP(s):-

3.1. Originating VTEP Procedure

When creating the VXLAN header for a given VXLAN segment, the Originating VTEP MUST set Router Alert Bit in the Flag bits in VXLAN header. The VNI for this frame MUST be the same as for the given VXLAN segment which carries the data traffic of the End System.

    VXLAN Header:
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |R|R|R|R|I|R|R|RA|           Reserved                           |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                VXLAN Network Identifier (VNI) |   Reserved    |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+           
		
    RA: Router Alter Bit (Proposed)
	 

3.2. Terminating VTEP Procedure

On receiving VXLAN frame, the Terminating VTEP would do the usual VXLAN processing as defined in [I-D.draft-mahalingam-dutt-dcops-vxlan], but if the RA Bit in Flags is Set it MUST send the rest of the inner frame for further processing to the above application. The details of the applications and how it would process the inner frame is outside the scope of this document. This frame MUST not be sent to the target End System.

4. Management Considerations

None

5. Security Considerations

TBD

6. Acknowledgements

The authors want to thank Diego Garcia Del Rio and Suresh Boddapati of Nuage Networksfor significant contribution and feedback.

7. IANA Considerations

Router Alter Bit (RA): IANA is request to assing 1 Bit in Flags field of VXLAN Header to communicate VXLAN Router Alert information.

8. References

8.1. Normative References

8.2. Informative References

Authors' Addresses