Internet DRAFT - draft-sarikaya-vxlan-qosmarking
draft-sarikaya-vxlan-qosmarking
Network Working Group B. Sarikaya
Internet-Draft Huawei USA
Expires: August 14, 2014 F. Xia
Huawei Technologies Co., Ltd.
February 10, 2014
Quality of Service Marking in Virtual eXtensible Local Area Network
draft-sarikaya-vxlan-qosmarking-00.txt
Abstract
The Virtual eXtensible Local Area Network enables multiple tenants to
operate in a data center. Each tenant needs to be assigned a
priority group to prioritize their traffic. Cloud carriers wish to
use quality of service to differentiate different applications. For
these purposes, three bits are assigned in the eXtensible Local Area
Network header. How these bits are assigned and are processed in the
network are explained in detail.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on August 14, 2014.
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
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
Sarikaya & Xia Expires August 14, 2014 [Page 1]
Internet-Draft Quality of Service Marking February 2014
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 4
4. QoS Bits in VXLAN Header . . . . . . . . . . . . . . . . . . . 4
5. Quality of Service Operation at VXLAN decapsulation point . . 6
6. Quality of Service Operation at VXLAN encapsulation point . . 7
7. QoS processing for VXLAN outer IP header . . . . . . . . . . . 8
8. Security Considerations . . . . . . . . . . . . . . . . . . . 8
9. IANA considerations . . . . . . . . . . . . . . . . . . . . . 8
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 8
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9
11.1. Normative References . . . . . . . . . . . . . . . . . . 9
11.2. Informative References . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 10
Sarikaya & Xia Expires August 14, 2014 [Page 2]
Internet-Draft Quality of Service Marking February 2014
1. Introduction
Data center networks are being increasingly used by telecom operators
as well as by enterprises. Currently these networks are organized as
one large Layer 2 network in a single building. In some cases such a
network is extended geographically using virtual Local Area Network
(VLAN) technologies still as an even larger Layer 2 network
connecting the virtual machines (VM), each with its own MAC address.
Another important requirement was growing demand for multitenancy,
i.e. multiple tenants each with their own isolated network domain.
In a data center hosting multiple tenants, each tenant may
independently assign MAC addresses and VLAN IDs and this may lead to
potential duplication.
What we need is IP based tunneling scheme based overlay network
called Virtual eXtensible Local Area Network (VXLAN). VXLAN overlays
a Layer 2 network over a Layer 3 network. Each overlay is identified
by the VXLAN Network Identifier (VNI). This allows up to 16M VXLAN
segments to coexist within the same administrative domain
[I-D.mahalingam-dutt-dcops-vxlan]. In VXLAN, each MAC frame is
transmitted after encapsulation, i.e. an outer Ethernet header, an
IPv4/IPv6 header, UDP header and VXLAN header are added. Outer
Ethernet header indicates an IPv4 or IPv6 payload. VXLAN header
contains 24-bit VNI.
VXLAN tunnel end point (VTEP) is the hypervisor on the server which
houses the VM. VXLAN encapsulation is only known to the VTEP, the VM
never sees it. Also the tunneling is stateless, each MAC frame is
encapsulated independent on any other MAC frame.
Instead of using UDP header, Generic Routing Encapsulation (GRE)
encapsulation can be used. A 24-bit Virtual Subnet Identifier (VSID)
is placed in the GRE key field. The resulting encapsulation is
called Network Virtualization using Generic Routing Encapsulation
(NVGRE) [I-D.sridharan-virtualization-nvgre]. Note that VSID is
similar to VNI. Although VXLAN terminology is used throughout, the
protocol defined in this document applies to VXLAN as well as NVGRE.
Since VXLAN allows multiple tenants to operate data center operators
are facing the problem of treating their traffic. There is interest
to provide different quality of service to the tenants based on their
service level agreements.
Cloud carriers have interest in different quality of service to
different applications such as voice, video, network control
applications, etc. In this case, quality of service marking can be
done using deep packet inspection (DPI) in order to detect the type
Sarikaya & Xia Expires August 14, 2014 [Page 3]
Internet-Draft Quality of Service Marking February 2014
of application in each packet.
In this document, we develop Quality of Service marking solution for
VXLAN.
2. Terminology
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]. The
terminology in this document is based on the definitions in
[I-D.mahalingam-dutt-dcops-vxlan]
3. Problem Statement
In a VXLAN network multiple tenants are supported. There is interest
in assigning different priority to each tenant's traffic based on the
premium that tenant paies, etc. In another words, cloud carriers
would like to categorize tenants into different traffic classes such
as diamond, gold, silver and bronze classes.
Cloud carriers wish to categorize the traffic based on the
application such as voice, video, etc. Based on the type of the
application different traffic classes may be identified and different
priority levels can be assigned to each.
In order to do these, quality of service marking is needed in VXLAN.
The solution proposed in this document is based on using VXLAN header
to mark by VXLAN tunnel end point (VTEP) when the frames are
introduced by the virtual machines.
4. QoS Bits in VXLAN Header
Three bits are reserved in VXLAN header flags field shown as QoS-flag
in Figure 1.
3 bits called QoS-flag are reserved to indicate the quality of
service class that this packet belongs. These bits will be assigned
according to the type of traffic carried in this flow, e.g. video,
voice, critical application, etc. These assignments will be
considered in assigning IP level Differentiated Services Field (DS
field), especially diff serv bits, see Section 7.
Sarikaya & Xia Expires August 14, 2014 [Page 4]
Internet-Draft Quality of Service Marking February 2014
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R|R|R|R|I|R|R|R| QoS | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VXLAN Network Identifier (VNI) | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: QoS Flag in VXLAN Header
001 - BK or background traffic
000 - BE or best effort traffic
010 - EE or Excellent Effort
011 - CA or Critical Applications
100 - VI or Video
101 - VO or Voice
110 - IC or Internetwork Control
111 - NC or Network Control
'111' has the highest priority while '001' has the lowest, for
example, video traffic has higher priority than web surfing which is
best effort traffic.
As can be seen the markings are the same as in IEEE 802.1p
[IEEE802.1D] which is supported by most switches currently deployed
that have the QoS capabilities.
Bits 8, 9 and 10 previously reserved are used to assign the quality
of service bits. The sender SHOULD assign bits 8-10 with bits
assigned values as above if the quality of service treatment is
needed on this packet. The sender should assign the same bit pattern
to all the packets of the same flow. The sender MUST assign all
other reserved bits to zero.
In real deployment, there are two different mappings to make use of
the QoS field.
The first one is based on application priorities. A VTEP uses some
mechanism such as Deep Packet Inspection (DPI) to identify
Sarikaya & Xia Expires August 14, 2014 [Page 5]
Internet-Draft Quality of Service Marking February 2014
application types, and fills in the QoS field of VXLAN encapsulation
based on the identified application types. The below is a possible
mapping.
001 - Reserved
000 - ftp/email
010 - web surfing
011 - instant Message
100 - video
101 - voice
110 - High Performance computation
111 - Reserved
The second one is based on tenancy priorities. A cloud carrier could
exploit the QoS bits in another different way. The cloud carrier
categorizes its tenants into different groups such as diamond, gold,
silver, bronze, standard and so on. All traffic for a diamond tenant
has a high priority to be forwarded regardless of application types.
The below is a possible mapping option.
001 - Reserved
000 - Standard
010 - Bronze
011 - Silver
100 - Gold
101 - Diamond
110 - Emergency
111 - Reserved
5. Quality of Service Operation at VXLAN decapsulation point
There are two types of VXLAN packets receivers, that is, a server or
a VXLAN gateway.
Sarikaya & Xia Expires August 14, 2014 [Page 6]
Internet-Draft Quality of Service Marking February 2014
When the server receives the packet, the server decapsulates the
packet and delivers it to a corresponding VM. If there are multiple
packets to be processed, packets with high priority (that is higher
QoS value) should be processed first.
The QoS operation is different for the VXLAN gateway processing. The
gateway which provides VXLAN tunnel termination functions could be
ToR/access switches or switches higher up in the data center network
topology. For incoming frames on the VXLAN connected interface, the
gateway strips out the VXLAN header and forwards to a physical port
based on the destination MAC address of the inner Ethernet frame. If
inner VLAN is included in the VXLAN frame or a VLAN is supposed to be
added based on configuration, the VXLAN gateway decapsulates the
VXLAN packet and remarks the QoS field of the outgoing Ethernet frame
based on VXLAN QoS bits. The switch SHOULD copy the Q-Flags of VXLAN
encapsulation into IEEE 802.1p Priory Code Point (PCP) field in VLAN
tag.
6. Quality of Service Operation at VXLAN encapsulation point
There are two types of VXLAN packet senders, that is, a server
hosting VMs or a VXLAN gateway.
For a server, the upstream procedure is:
Reception of Frames
The server receives an Ethernet packet from a hosting VM.
Lookup
Making use of the destination of the Ethernet packet, the server
looks up MAC-VTEP mapping table, and retrieves IP address of
destination VTEP.
Acquisition of QoS parameters
There are two different ways to acquire QoS parameters for VXLAN
encapsulation. The first is a dynamic one which requires a VTEP
has Deep Packet Inspection (DPI) capability and can identify
different application types. The second is a static one which
requires a VM manager to assign QoS parameters to different VNIs
based on premium that different tenancies pay.
Encapsulation of frames
The VTEP then encapsulates the packet using VXLAN format with
acquired QoS parameters and VNI. The specific format is given in
Section 4. After the frame is encapsulated it is sent out
upstream to the network.
Sarikaya & Xia Expires August 14, 2014 [Page 7]
Internet-Draft Quality of Service Marking February 2014
For a VXLAN gateway, packets are encapsulated using VXLAN format with
QoS field in a similar way. Once the VXLAN gateway receives a packet
from a non-VXLAN domain, it encapsulates the packet with QoS
parameters which are acquired through DPI or priorities of tenancies.
7. QoS processing for VXLAN outer IP header
QoS is user experience of end-to-end network operation. A packet
from VM A to VM B normally traverses such network entities
sequentially as virtual switch A which is co-located with VM A, TOR
switch A, aggregation switch A, a core switch, aggregation switch B,
TOR switch B, virtual switch B. VXLAN processing only takes place in
virtual switches, and all other network entities only execute IP
forwarding. VXLAN QoS mapping to outer IP header at virtual switch A
is needed to achieve end-to-end QoS.
Six bits of the Differentiated Services Field (DS field) are used as
a codepoint (DSCP) to select the per hop behaviour (PHB) a packet
experiences at each node in a Differentiated Services Domain
[RFC2474]. DS field is 8 bits long, 6 bits of it are used as DSCP
and two bits are unused. DS field is carried in both IPv4 and IPv6
packet headers. The first three bits of DS field are used for IP
precedence and the last three are used as diff serv bits. Three diff
serv bits are relevant for the markings in this document.
Similarly, when a packet forwarded from non-VXLAN domain to VXLAN
domain through a VXLAN gateway, DSCP field of outer IP header should
be marked based on VXLAN QoS.
8. Security Considerations
Special security considerations in [I-D.mahalingam-dutt-dcops-vxlan]
are applicable.
9. IANA considerations
IANA is requested to assign the Q-Flags bits in VXLAN reserved bits
in the header.
10. Acknowledgements
TBD.
Sarikaya & Xia Expires August 14, 2014 [Page 8]
Internet-Draft Quality of Service Marking February 2014
11. References
11.1. Normative References
[RFC0826] Plummer, D., "Ethernet Address Resolution Protocol: Or
converting network protocol addresses to 48.bit Ethernet
address for transmission on Ethernet hardware", STD 37,
RFC 826, November 1982.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black,
"Definition of the Differentiated Services Field (DS
Field) in the IPv4 and IPv6 Headers", RFC 2474,
December 1998.
[IEEE802.1D]
IEEE, "Virtual Bridged Local Area Networks", IEEE Std
802.1D-2005, May 2006.
11.2. Informative References
[I-D.mahalingam-dutt-dcops-vxlan]
Mahalingam, M., Dutt, D., Duda, K., Agarwal, P., Kreeger,
L., Sridhar, T., Bursell, M., and C. Wright, "VXLAN: A
Framework for Overlaying Virtualized Layer 2 Networks over
Layer 3 Networks", draft-mahalingam-dutt-dcops-vxlan-08
(work in progress), February 2014.
[I-D.sridharan-virtualization-nvgre]
Sridharan, M., Greenberg, A., Wang, Y., Garg, P.,
Venkataramiah, N., Duda, K., Ganga, I., Lin, G., Pearson,
M., Thaler, P., and C. Tumuluri, "NVGRE: Network
Virtualization using Generic Routing Encapsulation",
draft-sridharan-virtualization-nvgre-04 (work in
progress), February 2014.
Sarikaya & Xia Expires August 14, 2014 [Page 9]
Internet-Draft Quality of Service Marking February 2014
Authors' Addresses
Behcet Sarikaya
Huawei USA
5340 Legacy Dr. Building 3
Plano, TX 75024
Phone: +1 972-509-5599
Email: sarikaya@ieee.org
Frank Xia
Huawei Technologies Co., Ltd.
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012, China
Phone: ++86-25-56625443
Email: xiayangsong@huawei.com
Sarikaya & Xia Expires August 14, 2014 [Page 10]
