Internet DRAFT - draft-king-opsawg-time-multi-layer-oam-use-case
draft-king-opsawg-time-multi-layer-oam-use-case
Operations and Management Area Working Group D. King
Internet-Draft Old Dog Consulting
Intended status: Informational M. Boucadair
Expires: January 5, 2015 France Telecom
S. Aldrin
Huawei USA
G. Mirsky
Ericsson
Q. Wu
Huawei
July 4, 2014
Use Cases and Requirements for Transport-Independent Multiple Layer OAM
draft-king-opsawg-time-multi-layer-oam-use-case-01
Abstract
This document identifies and discusses use-cases and high level
requirements for transport technology independent OAM that need to
interface multi-layer or multi-domain transport networks to cover
heterogeneous networking technologies. As providers face multi-layer
networks and diverse transport technologies, generic and integrated
OAM is desirable for simplifying network operations and maintenance.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on January 5, 2015.
Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Conventions used in this document . . . . . . . . . . . . 3
2.2. Acronyms and Abbreviations . . . . . . . . . . . . . . . 3
3. Multi-Layer OAM use cases illustration . . . . . . . . . . . 4
3.1. Multi-layer multi-domain OAM Consolidated in the Data
Plane and Management Plane . . . . . . . . . . . . . . . 4
3.2. OAM at Top of Layer 3 . . . . . . . . . . . . . . . . . . 5
3.3. Overlay OAM . . . . . . . . . . . . . . . . . . . . . . . 7
4. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 8
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
6. Security Considerations . . . . . . . . . . . . . . . . . . . 9
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
7.1. Normative References . . . . . . . . . . . . . . . . . . 9
7.2. Informative References . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction
This document discusses use-cases for transport-independent OAM that
need to interface multi-layer or multi-domain transport networks to
cover heterogeneous networking technologies. As providers (e.g.,
network providers, data center providers, etc.) face multi-layer
networks and diverse transport technologies, generic and integrated
OAM is desirable for keeping network complexity down and simplifying
O&M (OAM and O&M are used as specified in [RFC6291]).
This document is part of Transport Independent OAM in Multi-Layer
Environment (TIME) effort which is meant to:
o Understand and discuss situations where an OAM protocol can be
tuned and optimized for a specific data plane.
o OAM consolidations in the data plane:
* Exchange OAM information at the service layer atop of layer 3.
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* Deployed over various encapsulating protocols, and in various
medium types.
o OAM consolidations in the management plane:
* Abstract OAM information common to different layers.
* Expose OAM information via unified interface to management
entities, independently of the layer they belong to.
* Discuss how information gathered from various layers can be
correlated for the sake of network operations optimization
purposes.
* Propose means to help during service diagnosis; these means may
rely on filtering information to be leaked to other layers so
that time recovery can be optimized. A typical example would
be efficient root cause analysis that is fed with input from
various layers.
* Propose means that would help to optimize a network as a whole
instead of the monolithic approach that is specific to a given
layer. For example, investigate means that would help in
computing diverse and completely disjoint paths, not only at
layer 3 but also at the physical layer.
These objectives are not frozen; further discussion is required to
target key issues and scope the work to be conducted within IETF
accordingly.
The problem statement and architecture is discussed in [TIME-PS].
2. Terminology
2.1. Conventions used in this document
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].
2.2. Acronyms and Abbreviations
TIME - Transport Independent OAM in Multi-Layer Environment
OAM - Operations, Administration, and Maintenance
O&M - OAM and Management
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3. Multi-Layer OAM use cases illustration
3.1. Multi-layer multi-domain OAM Consolidated in the Data Plane and
Management Plane
Figure 1 illustrates a multi-layer network in which IP traffic
between two customer edges is transported over both an IP/MPLS
provider network and an Ethernet/MPLS provider network and multiple
layers OAM are used. Ethernet OAM is used at the customer level for
monitoring the end-to-end connection between the two customer edges,
while IP OAM and MPLS OAM is used at the provider level for
monitoring the connection between any two provider edges in each
network. In addition to Ethernet OAM, transport independent OAM is
also used for monitor end to end connection between the two customer
edges at the abstract level.
Domain A Domain B
---------- ----------
//-IP/MPLS -\\ //Ethernet/MPLS
// \\ // \\
/ \ / \
|| || || ||
| | | |
+---+ +----+ +----+ +-------+ +----+ +----+ +---+
|CE |--| PE |------| P +---- | PE | ---- | P |-----| PE |--|CE |
+-+-+ +--+-+ +--+-+ +---+---+ +--+-+ +-+--+ +-+-+
| | | | | | | | | | |
| ||| | || | || | ||| |
| | | | | | | | |
| |\\ | // | \\ | //| |
| | \\- | -// | \\- | -// | |
| | ------+--- | -----+---- | |
L1 | |Ethernet OAM(CC,CV,etc.) | | |
o-------D-----------+--------+---o---+----------+---------D-------o
| | | | | | |
L2| | |IP OAM(Ping,|Traceroute, etc.) | |
o-------o-----------D-------- ---o--- ----------D---------o-------o
| | | | | | |
L?| Transport Independent OAM(Integrated Ethernet with IP OAM |
o-------o-----------D-------- ---o--- ----------D---------o-------o
| | | | | | |
| | | | | | |
o Maintenance Endpoint(MEP)
D Maintenance Intermediary point (MIP)
Figure 1: Multi-Domain Multi-Layer OAM
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With transport independent OAM in the data plane, a user who wishes
to issue a IP Ping Command or use connectivity verification command
can do so in the same manner regardless of the underlying protocol or
transport technology. Consider a scenario where both Ethernet OAM
and IP OAM can be decomposed into a set of various OAM functions and
an Ethernet OAM can be integrated with IP OAM in one protocol. When
one OAM function is invoked, it will be invoked in the same way as
the other OAM function regardless of the underlying protocol.
Alternatively, when Ethernet OAM and IP OAM can be consolidated
through uniformed interface at the management plane, A user who
wishes to issue a IP Ping command or a IP Traceroute or initiate a
session monitoring can also do so in the same manner regardless of
the underlying protocol or technology.
Consider a scenario where an IP ping to PE B from CE A failed.
Between CE A and PE B there are IEEE 802.1 [IEEE-802.1Q] bridges a,b
and c. Let's assume a,b and c are using [IEEE-802.1ag] CFM. Upon
detecting IP layer ping failure, the user may wish to "go down" to
the Ethernet layer and issue the corresponding fault verification
(LBM/LBR) and fault isolation (LTM/LTR) tools, using the same API.
3.2. OAM at Top of Layer 3
In Service Function Chain ([I-D.ietf-sfc-problem-statement]), the
service packets are steered through a set of Service Function Nodes
distributed in the network. Overlay technologies (or tunneling
techniques in general) can be used to stitch these Service Function
Nodes in order to form end to end path (see Figure 2).
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+--------+
|Unified |
+---------------------------+OSS/NMS +---------------------------+
| +--------+ |
| SFC-enabled Domain A SFC-enabled Domain B |
| ---------- ---------- |
| // IP/MPLS -\\ //- IP/MPLS -\\ |
+----+ // \\ // \\ |
|SF- | SN1 SN2 SN3 SN4 SN5 SN6 +-+--+
| |+++--+ +----| +--+++ +++--+ +----+ +--+++-|SF- |
|Ingr||SF1 | | | |SF4|| || | |SF7 | | || |Egr |
| ++ +------| +----+ +-+ +-----| +-----| +-+ |
|ess ||SF2 | | SF3| |SF5 | |SF6 | |SF8 | |SF9 | |ess |
+-+-+|+--+-+ +--+-+ +-+--+ +--+-+ +--+-+ +-+--+ |+-+-+
| | | | | | | | | | | |
| ||| | ||| ||| | ||| |
| | | | | | | |
| |\\ | //| |\\ | //| |
| | \\- | -// | | \\- | -// | |
| | ------+--- | | -----+---- | |
L1 | |Ethernet OAM(CC,CV, etc.) | | |
o-------D-----------+--------+-------+----------+---------D-------o
| | | | | | | |
L2 | |IP OAM(Ping, Traceroute, etc.) | |
o-------o-----------D--------o-------o----------D---------o-------o
| | | | | | | |
L3 Transport Independent OAM(Integrated Ethernet with IP OAM |
o-------o-----------D--------o-------o----------D---------o-------o
| | | | | | | |
| | | | | | | |
o Maintenance Endpoint(MEP)
D Maintenance Intermediary point (MIP)
Layer7- SF1 --------------------- SF6 ------- SF7-------------
Layer6------------------------F4 --------------------------------
Layer5------------ SF3-------SF5------------------------- SF9----
Layer4---SF2 ---------------------------------- SF8--------------
Figure 2: OAM at Top of Layer 3
When the service packet enters into the network, OAM information
needs to be imposed by ingress node of the network into the packet
(e.g., packet header extension or TLV extension in the overlay
header) and pass through the network in the same path as the service
traffic and processed by a set of Service Functions that are hosted
in Service Nodes and located in different layers at the top of layer
3.
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When any Service Nodes or any service segment between two Service
Nodes fails to deliver user traffic, there is a need to provide a
tool that would enable users to detect such failures, and a mechanism
to isolate faults.
In case of several SFs co-located in the same Service Node, the
packet is processed by all SFs in the Service Node, Once the packet
is successfully handled by one SF, the packet is forwarded to the
next SF that is in the same Service Node.
When the packet leaves the network, the OAM information needs to be
stripped out from the packet.
To provide unified view of OAM information common to different layers
and different domains, these OAM information needs to gathered from
various layer using different encapsulation and tunneling techniques
and abstracted and provided to the management application via the
unified management interface.
As indicated in [I-D.boucadair-sfc-requirements], the following OAM
functions are to be supported:
o Support means to verify the completion of the forwarding actions
until the SFC Border Node is reached (see Section 3.4.1 of
[RFC5706]).
o Support means to ensure coherent classification rules are
installed in and enforced by all the Classifiers of the SFC-
enabled domain.
o Support means to correlate classification policies with observed
forwarding actions.
o Support in-band liveliness and functionality checking mechanisms
for the instantiated Service Function Chains and the Service
Functions that belong to these chains.
Other service diagnosis and troubleshooting requirements are
discussed in [I-D.boucadair-sfc-requirements].
3.3. Overlay OAM
Overlay network is referred to a network that is built on top of
another underlying network and provides various services to tenant
system. With the growth of network virtualization technology, the
needs for inter-connection between various overlay technologies/
networks (e.g., VXLAN or NVGRE) in the Wide Area Network (WAN) become
important since it can provide end-to-end connectivity.
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Domain A Domain B
---------- ----------
//- IP/MPLS -\\ //- IP/MPLS -\\
// \\ // \\
/ \ / \
|| || || ||
| | | |
+---+ +----+ +----+ +----+ +----+ +----+ +----+ +---+
|CE |--| PE +------| P +----| PE +-+ PE +-----+ P +-----+ PE +--|CE |
+-+-+ +--+-+ +--+-+ +-+--+ +--+-+ +--+-+ +-+--+ +-+-+
| | | | | | | | | | | |
| ||| | ||| ||| | ||| |
| | | | | | | |
| |\\ | //| |\\ | //| |
| | \\- | -// | | \\- | -// | |
| | ------+--- | | -----+---- | |
L1 | |Ethernet OAM(CC,CV,etc) | | |
o-------D-----------+--------+-------+----------+---------D-------o
| | | | | | | |
| L2 | |IP OAM(Ping, Traceroute, etc.) |
o-----------D--------o-------o----------D---------o-
| | | | | |
o Maintenance Endpoint(MEP)
D Maintenance Intermediary point (MIP)
Figure 3: Overlay OAM
When a packet traverses a set of overlay networks in the data path,
each overlay network will comprise an overlay segment used to connect
overlay nodes in the same network and these overlay segment are
stitched together to form end to end data path (Figure 3).
When any Overlay Segment fails to deliver user traffic, there is a
need to provide a tool that would enable users to detect such
failures, and a mechanism to isolate faults. It may also be
desirable to test the data path before mapping user traffic to the
Overlay Segment.
4. Requirements
This section identifies high-level requirements to fulfill transport
independent OAM in Multi-layer Environment to support various use
cases discussed in the previous sections.
o The interfaces between the management entity and each Managed
device in the transport network domain SHOULD support standards-
based abstraction with a common information/data model.
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o The management entity should be able to create a single unified
view of OAM information that is common to various layers, various
domain and various operators.
o The following capability should be supported:
* Support customized service diagnostic.
* Support diagnose the availability of a end-to-end path.
* Support diagnose the availability of a segment Path that is
sub-path of end to end path.
* Support verification on the correct value of Path ID between
any two pair of overlay nodes or any two pair of service nodes.
* Support verifying Overlay Control Plane and Data Plane
consistency at either two overlay nodes or two service nodes.
* Support local diagnostic procedures specific to each Service
Node.
* Support in-band liveliness and functionality checking
mechanisms for the overlay node or service node.
* Support Trace on the underlying network.
5. IANA Considerations
This memo includes no request to IANA.
6. Security Considerations
TBD.
7. References
7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", March 1997.
[TIME-PS] Wu, Q., "Problem Statement and Architecture for Transport-
Independent Multiple Layer OAM", ID draft-ww-opsawg-multi-
layer-oam-01, June 2014.
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7.2. Informative References
[I-D.boucadair-sfc-requirements]
Boucadair, M., Jacquenet, C., Jiang, Y., Parker, R.,
Pignataro, C., and K. Kengo, "Requirements for Service
Function Chaining (SFC)", draft-boucadair-sfc-
requirements-05 (work in progress), July 2014.
[I-D.ietf-sfc-problem-statement]
Quinn, P. and T. Nadeau, "Service Function Chaining
Problem Statement", draft-ietf-sfc-problem-statement-07
(work in progress), June 2014.
[IEEE-802.1Q]
IEEE 802.1Q-2011, "IEEE standard for local and
metropolitan area networks: Media access control (MAC)
bridges and virtual bridged local area networks", August
2011.
[IEEE-802.1ag]
IEEE 802.1ag-2007, "IEEE Standard for Local and
Metropolitan Area Networks Virtual Bridged Local Area
Networks Amendment 5: Connectivity Fault Management",
December 2007.
[RFC5706] Harrington, D., "Guidelines for Considering Operations and
Management of New Protocols and Protocol Extensions", RFC
5706, November 2009.
[RFC6291] Andersson, L., Helvoort, H., Bonica, R., Romascanu, D.,
and S. Mansfield, "Guidelines for the Use of the "OAM"
Acronym in the IETF", RFC 6291, June 2011.
Authors' Addresses
Daniel King
Old Dog Consulting
UK
Email: daniel@olddog.co.uk
Mohamed Boucadair
France Telecom
Rennes 35000
France
Email: mohamed.boucadair@orange.com
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Sam Aldrin
Huawei Technologies USA
2330 Central Expressway
NSanta Clara, CA 95051
USA
Email: aldrin.ietf@gmail.com
Greg Mirsky
Ericsson
Email: gregory.mirsky@ericsson.com
Qin Wu
Huawei
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Email: bill.wu@huawei.com
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