One document matched: draft-xia-nvo3-vxlan-qosmarking-01.txt
Differences from draft-xia-nvo3-vxlan-qosmarking-00.txt
Network Working Group F. Xia
Internet-Draft B. Sarikaya
Expires: May 14, 2015 Huawei Technologies Co., Ltd.
November 10, 2014
Quality of Service Marking in Virtual eXtensible Local Area Network
draft-xia-nvo3-vxlan-qosmarking-01.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, six 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
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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 May 14, 2015.
Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
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include Simplified BSD License text as described in Section 4.e of
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 3
4. QoS Bits in VXLAN Header . . . . . . . . . . . . . . . . . . 3
5. Quality of Service Operation at VXLAN Decapsulation Point . . 6
6. Quality of Service Operation at VXLAN encapsulation point . . 6
7. QoS processing for VXLAN outer IP header . . . . . . . . . . 7
8. Security Considerations . . . . . . . . . . . . . . . . . . . 7
9. IANA considerations . . . . . . . . . . . . . . . . . . . . . 8
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
11.1. Normative References . . . . . . . . . . . . . . . . . . 8
11.2. Informative References . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
Data center networks are being increasingly used by telecom operators
as well as by enterprises. An important requirement in data center
networks is multitenancy, i.e. multiple tenants each with their own
isolated network domain. Virtual eXtensible Local Area Network
(VXLAN) is a solution that is gaining polularity in industry
[RFC7348]. VXLAN overlays a Layer 2 network over a Layer 3 network.
Each overlay is identified by the VXLAN Network Identifier (VNI).
VXLAN tunnel end point (VTEP) can be hosted at the the hypervisor on
the server or higher above in the network. VXLAN encapsulation with
a UDP header is only known to the VTEP, the Virtual Machines (VM)
never sees it.
It should be noted that in this document, VTEP plays the role of the
Network Virtualization Edge (NVE) according to NVO3 architecture for
overlay networks like VXLAN or NVGRE defined in [I-D.ietf-nvo3-arch].
NVE interfaces the tenant system underneath with the L3 network
called the Virtual Network (VN).
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
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done using deep packet inspection (DPI) in order to detect the type
of application in each packet.
In this document, we develop Quality of Service marking solution for
VXLAN. The solution is compatible with IP level Differentiated
Services model or diffserv described in [RFC2474] and [RFC2475].
Configuration guidelines are described in [RFC4594]. Diffserv
interconnection classes and interconnection practice are described in
[I-D.geib-tsvwg-diffserv-intercon].
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
[RFC7348].
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 Network Virtualization Edge (NVE) when the frames are
introduced by the virtual machines.
4. QoS Bits in VXLAN Header
Six bits are reserved in VXLAN header flags field shown as QoS-flag
in Figure 1.
6 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 made
adopting IP level Differentiated Services model, diff serv bits or DS
field, see Section 7.
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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| QoS | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| VXLAN Network Identifier (VNI) | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: QoS Flag in VXLAN Header
The first three bits (bits 5-7) are precedence bits. They are
assigned according to [RFC0791]. Precedence values '110' and '111'
are selected for routing traffic.
The last three bits (bits 8-10) are class selector bits. Thet are
assigned as follows:
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 5,6 and 7 previously reserved are used to assign precedence.
Bits 8, 9 and 10 previously reserved are used to assign the class
selector 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
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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 class selector QoS field.
The first one is based on application priorities. NVE uses some
mechanism such as Deep Packet Inspection (DPI) to identify
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
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111 - Reserved
5. Quality of Service Operation at VXLAN Decapsulation Point
There are two types of VXLAN packets receivers, that is, a VXLAN
enabled NVE or a VXLAN gateway [I-D.sarikaya-nvo3-proxy-vxlan].
When the VXLAN enabled NVE receives the packet, it decapsulates the
packet and delivers it downstream 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 class selector QoS bits. The switch SHOULD copy the
class selector 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 VXLAN enabled
NVE or a VXLAN gateway.
For a VXLAN enabled NVE, the upstream procedure is:
Reception of Frames
The VXLAN enabled NVE receives an Ethernet packet from a hosting
VM.
Lookup
Making use of the destination of the Ethernet packet, the VXLAN
enabled NVE looks up MAC-NVE mapping table, and retrieves IP
address of destination NVE.
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 VXLAN
enabled NVE has Deep Packet Inspection (DPI) capability and can
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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 NVE 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.
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. VXLAN
outer IP header's DSCP field SHOULD be copied from VXLAN header QoS
bits.
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 [RFC7348] are applicable.
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9. IANA considerations
IANA is requested to assign the Q-Flags bits in VXLAN reserved bits
in the header.
10. Acknowledgements
The authors are grateful to David Black and Brian Carpenter for their
constructive comments on our work.
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.
[RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791, September
1981.
[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.
[RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.,
and W. Weiss, "An Architecture for Differentiated
Services", RFC 2475, December 1998.
[RFC2597] Heinanen, J., Baker, F., Weiss, W., and J. Wroclawski,
"Assured Forwarding PHB Group", RFC 2597, June 1999.
[RFC4594] Babiarz, J., Chan, K., and F. Baker, "Configuration
Guidelines for DiffServ Service Classes", RFC 4594, August
2006.
[I-D.ietf-nvo3-arch]
Black, D., Hudson, J., Kreeger, L., Lasserre, M., and T.
Narten, "An Architecture for Overlay Networks (NVO3)",
draft-ietf-nvo3-arch-02 (work in progress), October 2014.
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[IEEE802.1D]
IEEE, "Virtual Bridged Local Area Networks", IEEE Std
802.1D-2005, May 2006.
11.2. Informative References
[RFC7348] Mahalingam, M., Dutt, D., Duda, K., Agarwal, P., Kreeger,
L., Sridhar, T., Bursell, M., and C. Wright, "Virtual
eXtensible Local Area Network (VXLAN): A Framework for
Overlaying Virtualized Layer 2 Networks over Layer 3
Networks", RFC 7348, August 2014.
[I-D.geib-tsvwg-diffserv-intercon]
Geib, R. and D. Black, "DiffServ interconnection classes
and practice", draft-geib-tsvwg-diffserv-intercon-07 (work
in progress), October 2014.
[I-D.sarikaya-nvo3-proxy-vxlan]
Sarikaya, B. and F. Xia, "Virtual eXtensible Local Area
Network over IEEE 802.1Qbg", draft-sarikaya-nvo3-proxy-
vxlan-00 (work in progress), October 2014.
Authors' Addresses
Frank Xia
Huawei Technologies Co., Ltd.
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012, China
Phone: ++86-25-56625443
Email: xiayangsong@huawei.com
Behcet Sarikaya
Huawei Technologies Co., Ltd.
5340 Legacy Dr. Building 3
Plano, TX 75024
Phone: +1 972-509-5599
Email: sarikaya@ieee.org
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