NVO3 Working Group G. Fioccola
Internet-Draft Telecom Italia
Intended status: Standards Track G. Mirsky
Expires: September 3, 2018 ZTE Corp.
T. Mizrahi
Marvell
March 2, 2018
Performance Measurement (PM) with Alternate Marking in Network
Virtualization Overlays (NVO3)
draft-fmm-nvo3-pm-alt-mark-01
Abstract
This document describes how the alternate marking method can be used
for performance measurement method in a Network Virtualization
Overlays (NVO3) Domain. The description aims to be general for NVO3
encapsulations, but is focused to Geneve, recommended by the NVO3
design team [I-D.ietf-nvo3-encap].
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 https://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 September 3, 2018.
Copyright Notice
Copyright (c) 2018 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
(https://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
Fioccola, et al. Expires September 3, 2018 [Page 1]
Internet-Draft PM with Alternate Marking in NVO3 March 2018
to this document. Code Components extracted from this document must
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 . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions used in this document . . . . . . . . . . . . . . 2
2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2.2. Requirements Language . . . . . . . . . . . . . . . . . . 3
3. OAM Performance Measurement in a NVO3 Domain . . . . . . . . 3
4. The Mark Field in the NVO3 Header . . . . . . . . . . . . . . 5
5. Theory of Operation . . . . . . . . . . . . . . . . . . . . . 6
5.1. Single Mark Enabled Measurement . . . . . . . . . . . . . 6
5.2. Double Mark Enabled Measurement . . . . . . . . . . . . . 7
6. Multipoint Measurement Considerations . . . . . . . . . . . . 8
7. The Mark Field in Geneve . . . . . . . . . . . . . . . . . . 8
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
8.1. Mark Field in Geneve Header . . . . . . . . . . . . . . . 8
9. Security Considerations . . . . . . . . . . . . . . . . . . . 9
10. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 9
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
11.1. Normative References . . . . . . . . . . . . . . . . . . 9
11.2. Informative References . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction
[RFC7365] provides a framework for Data Center (DC) Network
Virtualization over Layer 3 (NVO3) tunnels. It is intended to aid in
standardizing protocols and mechanisms to support large-scale network
virtualization for data centers.
[RFC8321] describes a performance measurement method, which can be
used to measure packet loss, latency and jitter on live traffic.
Since this method is based on marking consecutive batches of packets
the method often referred to as the Alternate Marking Method (AMM).
This document defines how the alternate marking method can be used to
measure packet loss and delay metrics of an NVO3 Domain.
2. Conventions used in this document
Fioccola, et al. Expires September 3, 2018 [Page 2]
Internet-Draft PM with Alternate Marking in NVO3 March 2018
2.1. Terminology
AMM: Alternate Marking Method
OAM: Operations, Administration and Maintenance
NVO3: Network Virtualization Overlays
NVE: Network Virtualization Edge
VNI: Virtual Network Instance
DC: Data Center
NVA: Network Virtualization Authority
Geneve: Generic Network Virtualization Encapsulation
VXLAN: Virtual Extensible LAN
GUE: Generic UDP Encapsulation
2.2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. OAM Performance Measurement in a NVO3 Domain
Figure 1 shows the generic reference model for a DC network
virtualization over an L3 infrastructure while Figure 2 shows the
generic reference model for the Network Virtualization Edge (NVE).
Both Figures are taken from [RFC7365] and [RFC8014].
Fioccola, et al. Expires September 3, 2018 [Page 3]
Internet-Draft PM with Alternate Marking in NVO3 March 2018
+--------+ +--------+
| Tenant +--+ +----| Tenant |
| System | | (') | System |
+--------+ | ................. ( ) +--------+
| +---+ +---+ (_)
+--|NVE|---+ +---|NVE|-----+
+---+ | | +---+
/ . +-----+ .
/ . +--| NVA |--+ .
/ . | +-----+ \ .
| . | \ .
| . | Overlay +--+--++--------+
+--------+ | . | Network | NVE || Tenant |
| Tenant +--+ . | | || System |
| System | . \ +---+ +--+--++--------+
+--------+ .....|NVE|.........
+---+
|
|
=====================
| |
+--------+ +--------+
| Tenant | | Tenant |
| System | | System |
+--------+ +--------+
Figure 1: Generic Reference Model for DC Network Virtualization
Overlays (RFC7365)
+-------- L3 Network -------+
| |
| Tunnel Overlay |
+------------+---------+ +---------+------------+
| +----------+-------+ | | +---------+--------+ |
| | Overlay Module | | | | Overlay Module | |
| +---------+--------+ | | +---------+--------+ |
| |VN Context| | VN Context| |
| | | | | |
| +--------+-------+ | | +--------+-------+ |
| | |VNI| . |VNI| | | | |VNI| . |VNI| |
NVE1 | +-+------------+-+ | | +-+-----------+--+ | NVE2
| | VAPs | | | | VAPs | |
+----+------------+----+ +----+-----------+-----+
| | | |
| | | |
Tenant Systems Tenant Systems
Figure 2: Generic NVE Reference Model (RFC7365)
Fioccola, et al. Expires September 3, 2018 [Page 4]
Internet-Draft PM with Alternate Marking in NVO3 March 2018
L3 networks provide transport for an emulated Layer 2 created by NVE
devices. The connectivity between the NVE devices is achieved with
unicast and multicast tunneling methods. Then, the NVE devices
present an emulated Layer 2 network to the Tenant End Systems at a
Virtual Network Instance (VNI) through Virtual Access Points (VAPs).
The NVE devices map Layer 2 unicast to Layer 3 unicast point-to-point
tunnels and may either map Layer 2 multicast to Layer 3 multicast
tunnels or may replicate packets onto multiple Layer 3 unicast
tunnels.
The emulated Layer 2 network is provided by the NVE devices to which
the Tenant End Systems are connected. This network of NVE can be
operated by a single service provider or can span across multiple
administrative domains. Likewise, the L3 Overlay Network can be
operated by a single service provider or span across multiple
administrative domains.
Each of the layers is responsible for its own OAM. Complex OAM
relationships exist as a result of the hierarchical layering, but
this is out of scope here.
When we refer to an OAM domain considered in this document we refer
to a set of NVEs and the tunnels which interconnect them.
It is commonly agreed that NVO3 OAM Performance Management supports
measurements (packet loss, delay and jitter) per VNI between two NVE
devices that support the same VNI within a given NVO3 domain.
4. The Mark Field in the NVO3 Header
This document defines a two-bit long field, referred to as Mark field
(M), as part of the NVO3 Header and designated for the alternate
marking performance measurement method [RFC8321]. The Mark field
MUST NOT be used in defining forwarding and/or quality of service
treatment of a NVO3 packet. The Mark field MUST be used only for the
performance measurement of data traffic in the NVO3 layer. Since the
field does not affect forwarding and/or quality of service treatment
of packets, the alternate marking method in the NVO3 layer can be
viewed as nearly-passive performance measurement method.
The Figure 3 displays the format of the Mark field.
Fioccola, et al. Expires September 3, 2018 [Page 5]
Internet-Draft PM with Alternate Marking in NVO3 March 2018
0
0 1
+-+-+-+-+
| L | D |
+-+-+-+-+
Figure 3: Mark field (M) format
where:
o L - Loss bit;
o D - Delay bit.
5. Theory of Operation
The marking method can be used in NVO3. For example, one can
consider the NVO3 reference model presented in Figure 1. AMM can be
applied at either ingress or egress NVE to detect performance
degradation defect and localize it efficiently.
Using AMM, NVE1 creates distinct sub-flows. Each sub-flow consists
of consecutive blocks that are unambiguously recognizable by a
monitoring point at any component of the NVO3, e.g. NVE2 or NVE3,
and can be measured to calculate packet loss and/or packet delay
metrics.
Every NVO3 Header [I-D.ietf-nvo3-geneve], [I-D.ietf-nvo3-vxlan-gpe]
and [I-D.ietf-nvo3-gue] can be considered for the application of AMM.
5.1. Single Mark Enabled Measurement
As explained in the [RFC8321], marking can be applied to delineate
blocks of packets based either on equal number of packets in a block
or based on equal time interval. The latter method offers better
control as it allows better account for capabilities of downstream
nodes to report statistics related to batches of packets and, at the
same time, time resolution that affects defect detection interval.
If the Single Mark measurement used, then the D flag MUST be set to
zero on transmit and ignored by monitoring point.
The L flag is used to create alternate flows to measure the packet
loss by switching value of the L flag every N-th packet or at certain
time intervals. Delay metrics MAY be calculated with the alternate
flow using any of the following methods:
Fioccola, et al. Expires September 3, 2018 [Page 6]
Internet-Draft PM with Alternate Marking in NVO3 March 2018
o First/Last Packet Delay calculation: whenever the marking, i.e.
value of L flag, changes a component of the NVO3 can store the
timestamp of the first/last packet of the block. The timestamp
can be compared with the timestamp of the packet that arrived in
the same order through a monitoring point at downstream component
of the NVO3 to compute packet delay. Because timestamps collected
based on order of arrival this method is sensitive to packet loss
and re-ordering of packets
o Average Packet Delay calculation: an average delay is calculated
by considering the average arrival time of the packets within a
single block. A component of the NVO3 may collect timestamps for
each packet received within a single block. Average of the
timestamp is the sum of all the timestamps divided by the total
number of packets received. Then difference between averages
calculated at two monitoring points is the average packet delay on
that segment. This method is robust to out of order packets and
also to packet loss (only a small error is introduced). This
method only provides single metric for the duration of the block
and it doesn't give the minimum and maximum delay values. This
limitation could be overcome by reducing the duration of the block
by means of an highly optimized implementation of the method.
5.2. Double Mark Enabled Measurement
Double Mark method allows measurement of minimum and maximum delays
for the monitored flow but it requires more nodal and network
resources. If the Double Mark method used, then the L flag MUST be
used to create the alternate flow, i.e. mark larger batches of
packets. The D flag MUST be used to mark single packets to measure
delay jitter.
The first marking (L flag alternation) is needed for packet loss and
also for average delay measurement. The second marking (D flag is
put to one) creates a new set of marked packets that are fully
identified over NVO3, so that a component can store the timestamps of
these packets; these timestamps can be compared with the timestamps
of the same packets on another component of the NVO3 to compute
packet delay values for each packet. The number of measurements can
be easily increased by changing the frequency of the second marking.
But the frequency of the second marking must be not too high in order
to avoid out of order issues. This method is useful to have not only
the average delay but also the minimum and maximum delay values and,
in wider terms, to know more about the statistic distribution of
delay values.
Fioccola, et al. Expires September 3, 2018 [Page 7]
Internet-Draft PM with Alternate Marking in NVO3 March 2018
6. Multipoint Measurement Considerations
The Multipoint characteristics of the traffic within a given NVO3
Domain could be considered a valuable Use Case of
[I-D.fioccola-ippm-multipoint-alt-mark].
7. The Mark Field in Geneve
[I-D.ietf-nvo3-geneve] defines format of the Geneve Header.
The design team recommendations in [I-D.ietf-nvo3-encap] section 7
concluded that Geneve is most suitable as a starting point for
proposed standard for network virtualization.
In addition, the design team recommended to address requirements for
OAM considerations for alternate marking and for performance
measurements that need 2 bits in the header. This document clarifies
the need of the current OAM bit in the Geneve Header.
Geneve Header:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Ver| Opt Len |O|C| M | Rsvd. | Protocol Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Virtual Network Identifier (VNI) | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Variable Length Options |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Geneve Header
This document defines a two-bit long field, referred to as the Mark
field (M in Figure 4, as part of Geneve and designated for the
alternate marking performance measurement method [RFC8321]. The Mark
field MUST NOT be used in defining forwarding and/or quality of
service treatment of a NVO3 packet. The Mark field MUST be used only
for the performance measurement of data traffic in NVO3 layer. Since
the field does not affect forwarding and/or quality of service
treatment of packets, the alternate marking method in the NVO3 layer
can be viewed as nearly-passive performance measurement method.
8. IANA Considerations
8.1. Mark Field in Geneve Header
This document requests IANA to allocate Mark field as two bits-long
field from Geneve Header Reserved Bits [I-D.ietf-nvo3-geneve].
Fioccola, et al. Expires September 3, 2018 [Page 8]
Internet-Draft PM with Alternate Marking in NVO3 March 2018
This document requests IANA to register values of the Mark field of
Geneve as the following:
+--------------+---------+--------------------------+---------------+
| Bit Position | Marking | Description | Reference |
+--------------+---------+--------------------------+---------------+
| 0 | L | Single Mark Measurement | This document |
| 1 | D | Double Mark Measurement | This document |
+--------------+---------+--------------------------+---------------+
Table 1: Mark field of Geneve
9. Security Considerations
This document lists the OAM requirement for NVO3 domain and does not
raise any security concerns or issues in addition to ones common to
networking and NVO3.
10. Acknowledgement
TBD
11. References
11.1. Normative References
[I-D.ietf-nvo3-encap]
Boutros, S., Ganga, I., Garg, P., Manur, R., Mizrahi, T.,
Mozes, D., Nordmark, E., Smith, M., Aldrin, S., and I.
Bagdonas, "NVO3 Encapsulation Considerations", draft-ietf-
nvo3-encap-01 (work in progress), October 2017.
[I-D.ietf-nvo3-geneve]
Gross, J., Ganga, I., and T. Sridhar, "Geneve: Generic
Network Virtualization Encapsulation", draft-ietf-
nvo3-geneve-05 (work in progress), September 2017.
[I-D.ietf-nvo3-gue]
Herbert, T., Yong, L., and O. Zia, "Generic UDP
Encapsulation", draft-ietf-nvo3-gue-05 (work in progress),
October 2016.
[I-D.ietf-nvo3-vxlan-gpe]
Maino, F., Kreeger, L., and U. Elzur, "Generic Protocol
Extension for VXLAN", draft-ietf-nvo3-vxlan-gpe-05 (work
in progress), October 2017.
Fioccola, et al. Expires September 3, 2018 [Page 9]
Internet-Draft PM with Alternate Marking in NVO3 March 2018
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
11.2. Informative References
[I-D.fioccola-ippm-multipoint-alt-mark]
Fioccola, G., Cociglio, M., Sapio, A., and R. Sisto,
"Multipoint Alternate Marking method for passive and
hybrid performance monitoring", draft-fioccola-ippm-
multipoint-alt-mark-02 (work in progress), March 2018.
[RFC7365] Lasserre, M., Balus, F., Morin, T., Bitar, N., and Y.
Rekhter, "Framework for Data Center (DC) Network
Virtualization", RFC 7365, DOI 10.17487/RFC7365, October
2014, <https://www.rfc-editor.org/info/rfc7365>.
[RFC8014] Black, D., Hudson, J., Kreeger, L., Lasserre, M., and T.
Narten, "An Architecture for Data-Center Network
Virtualization over Layer 3 (NVO3)", RFC 8014,
DOI 10.17487/RFC8014, December 2016,
<https://www.rfc-editor.org/info/rfc8014>.
[RFC8321] Fioccola, G., Ed., Capello, A., Cociglio, M., Castaldelli,
L., Chen, M., Zheng, L., Mirsky, G., and T. Mizrahi,
"Alternate-Marking Method for Passive and Hybrid
Performance Monitoring", RFC 8321, DOI 10.17487/RFC8321,
January 2018, <https://www.rfc-editor.org/info/rfc8321>.
Authors' Addresses
Giuseppe Fioccola
Telecom Italia
Via Reiss Romoli, 274
Torino 10148
Italy
Email: giuseppe.fioccola@telecomitalia.it
Fioccola, et al. Expires September 3, 2018 [Page 10]
Internet-Draft PM with Alternate Marking in NVO3 March 2018
Greg Mirsky
ZTE Corp.
Email: gregimirsky@gmail.com
Tal Mizrahi
Marvell
6 Hamada St.
Yokneam
Israel
Email: talmi@marvell.com
Fioccola, et al. Expires September 3, 2018 [Page 11]