TRILL Working Group Tissa Senevirathne
Internet Draft CISCO
Intended status: Informational David Bond
IBM
Sam Aldrin
Yizhou Li
Huawei
Rohit Watve
CISCO
November 5, 2012
Expires: May 2013
Requirements for Operations, Administration and Maintenance (OAM) in
TRILL
draft-ietf-trill-oam-req-03
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Abstract
OAM (Operations, Administration and Maintenance) is a general term
used to identify functions and toolsets to troubleshoot and monitor
networks. This document presents, OAM Requirements applicable to
TRILL.
Table of Contents
1. Introduction...................................................3
1.1. Scope.....................................................3
2. Conventions used in this document..............................3
3. Terminology....................................................3
4. OAM Requirements...............................................4
4.1. Data Plane................................................4
4.2. Connectivity Verification.................................5
4.2.1. Unicast..............................................5
4.2.2. Multicast............................................5
4.3. Continuity Check..........................................6
4.4. Path Tracing..............................................6
4.5. General Requirements......................................6
4.6. Performance Monitoring....................................7
4.6.1. Packet Loss..........................................7
4.6.2. Packet Delay.........................................8
4.7. ECMP Utilization..........................................8
4.8. Security and Operational considerations...................8
4.9. Fault Indications.........................................9
4.10. Defect Indications.......................................9
4.11. Live Traffic monitoring..................................9
5. Security Considerations.......................................10
6. IANA Considerations...........................................10
7. References....................................................10
7.1. Normative References.....................................10
7.2. Informative References...................................10
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8. Acknowledgments...............................................11
9. Contributing Authors..........................................11
1. Introduction
OAM (Operations, Administration and Maintenance) generally covers
various production aspects of a network. In this document we use the
term OAM as defined in [RFC6291].
Success of any mission critical network depends on the ability to
proactively monitor networks for faults, performance, etc. as well
as its ability to efficiently and quickly troubleshoot defects and
failures. A well-defined OAM toolset is a vital requirement for
wider adoption of TRILL as the next generation data forwarding
technology in larger networks such as data centers.
In this document we define the Requirements for TRILL OAM. It is
assumed that the readers are familiar with the OAM concepts and
terminologies defined in other OAM standards such as [8021ag]and
[RFC5860]. This document does not attempt to redefine the terms and
concepts specified elsewhere.
1.1. Scope
The scope of this document is OAM between RBridges of a TRILL campus
over links selected by TRILL routing.
2. 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 RFC-2119 [RFC2119].
Although this document is not a protocol specification, the use of
this language clarifies the instructions to protocol designers
producing solutions that satisfy the requirements set out in this
document.
3. Terminology
Section: The term Section refers to a partial segment of a path
between any two given RBridges. As an example, consider the case
where RB1 is connected to RBx via RB2,RB3 and RB4. The segment
between RB2 to RB4 is referred to as a Section of the path RB1 to
RBx.
Flow: The term Flow indicates a set of packets that share the same
path and per-hop behavior (such as priority). A flow is typically
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identified by a portion of the inner payload that affects the hop-by
hop forwarding decisions. This may contain Layer 2 through Layer 4
information.
All Selectable Least Cost Paths: The term "all selectable least cost
paths" refers to a subset of all potentially available least cost
paths to a specified destination RBridge that are available (and
usable) for forwarding of frames. It is important to note, in
practice, due to limitations in implementations, not all available
least cost paths may be selectable for forwarding.
Connectivity: The term connectivity indicates reachability between
an arbitrary RBridge RB1 and any other RBridge RB2. The specific
path can be either explicit (i.e. associated with a specific flow)
or unspecified. Unspecified means that messages used for
connectivity verification take whatever path the RBs happen to
select.
Continuity Verification: Continuity Verification refers to proactive
verification of Connectivity between two RBridges at periodic
intervals and generation of explicit notification when Connectivity
failures occur.
Fault: The term Fault refers to an inability to perform a required
action, e.g., an unsuccessful attempt to deliver a packet.
Defect: The term Defect refers to an interruption in the normal
operation, such that over a period of time no packets are delivered
successfully.
Failure: The term Failure refers to the termination of the required
function over a longer period of time. Persistence of a defect for a
period of time is interpreted as a failure.
Simulated Flow: The term simulated flow refers to a sequence of OAM
generated packets designed to follow a specific path. The fields of
the packets in the simulated flow may or may not be identical to the
fields of data packets of an actual flow being simulated. However,
the purpose of the simulated flow is to have OAM packets of the
simulated flow follow a specific path.
4. OAM Requirements
4.1. Data Plane
OAM frames, utilized for connectivity verification, continuity
checks, performance measurements, etc., will by default take
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whatever path TRILL chooses based on the current topology and per-
hop equal cost path choices. In some cases, it may be required that
the OAM frames utilize specific paths. Thus, it MUST be possible to
arrange that OAM frames follow the path taken by a specific flow.
RBridges MUST have the ability to identify OAM frames destined for
them or which require processing by the OAM plane from normal data
frames.
TRILL OAM frames MUST remain within a TRILL campus and MUST NOT be
egressed from a TRILL network as native frames.
OAM MUST have ability to include all Ethernet traffic types carried
by TRILL.
4.2. Connectivity Verification
4.2.1. Unicast
From an arbitrary RBridge RB1, OAM MUST have the ability to verify
connectivity to any other RBridge RB2.
From an arbitrary RBridge RB1, OAM MUST have the ability to verify
connectivity to any other RBridge RB2 for a specific flow via the
path associated with the specified flow.
An RBridge SHOULD have the ability to verify the above connectivity
tests on sections. As an example, assume RB1 is connected to RB5 via
RB2, RB3 and RB4. An operator SHOULD be able to verify the RB1 to
RB5 connectivity on the section from RB3 to RB5. The difference is
that the ingress and egress TRILL nicknames in this case are RB1 and
RB5 as opposed to RB3 and RB5, even though the message itself may
originate at RB3.
4.2.2. Multicast
OAM MUST have the ability to verify connectivity, from an arbitrary
RBridge RB1, to either a specific set of RBridges or all member
RBridges, for a specified multicast tree. This functionality is
referred to as verification of the un-pruned multicast tree.
OAM MUST have the ability to verify connectivity, from an arbitrary
RBridge RB1, to either a specific set of RBridges or all member
RBridges, for a specified multicast tree and for a specified flow.
This functionality is referred to as verification of the pruned
tree.
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4.3. Continuity Check
OAM MUST provide functions that allow any arbitrary RBridge RB1 to
perform a Continuity Check to any other RBridge.
OAM MUST provide functions that allow any arbitrary RBridge RB1 to
perform a Continuity Check to any other RBridge using a path
associated with a specified flow.
OAM SHOULD provide functions that allow any arbitrary RBridge to
perform a Continuity Check to any other RBridge over all selectable
least cost paths.
OAM SHOULD provide the ability to perform a Continuity Check on
sections of any selectable path within the network.
OAM SHOULD provide the ability to perform a multicast Continuity
Check for specified multi-destination tree(s) as well as specified
multi-destination tree and flow combinations. The former is referred
to as an un-pruned multi-destination tree Continuity Check and the
latter is referred to as a pruned tree Continuity Check.
4.4. Path Tracing
OAM MUST provide the ability to trace a path between any two
RBridges per specified unicast flow.
OAM SHOULD provide the ability to trace all selectable least cost
paths between any two RBridges.
OAM SHOULD provide functionality to trace all branches of a
specified multi-destination tree (un-pruned tree)
OAM SHOULD provide functionality to trace all branches of a
specified multi-destination tree for a specified flow (pruned tree).
4.5. General Requirements
OAM MUST provide the ability to initiate and maintain multiple
concurrent sessions for multiple OAM functions between any arbitrary
RBridge RB1 to any other RBridge. In general, multiple OAM
operations will run concurrently. For example, proactive continuity
checks may take place between RB1 and RB2 at the same time an
operator decides to test connectivity between the same two RBs.
Multiple OAM functions and instances of those functions MUST be able
to run concurrently without interfering with each other.
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OAM MUST provide a single OAM framework for all TRILL OAM functions
within the scope of this document.
OAM, as practical and as possible, SHOULD provide a single framework
between TRILL and other similar standards.
OAM MUST maintain related error and operational counters. Such
counters MUST be accessible via network management applications
(e.g. SNMP).
OAM functions related to continuity and connectivity checks MUST be
able to be invoked either proactively or on-demand.
OAM MAY be required to provide the ability to specify a desired
response mode for a specific OAM message. The desired response mode
can be either in-band, out-of band or none.
The OAM Framework MUST be extensible to future needs of TRILL and
the needs of other standard organizations.
OAM MAY provide methods to verify control plane and forwarding plane
alignments.
OAM SHOULD leverage existing OAM technologies, where practical.
4.6. Performance Monitoring
4.6.1. Packet Loss
In this document, the term loss of a packet is used as defined in
[RFC2680] (see Section 2.4 of RFC2680).
OAM SHOULD provide the ability to measure packet loss statistics for
a simulated flow from any arbitrary RBridge RB1 to any other
RBridge.
OAM SHOULD provide the ability to measure packet loss statistics
over a segment, for a simulated flow between any arbitrary RBridge
RB1 to any other RBridge.
OAM SHOULD provide the ability to measure simulated packet loss
statistics between any two RBridges over all least cost paths.
An RBridge SHOULD be able to perform the above packet loss
measurement functions either proactively or on-demand.
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4.6.2. Packet Delay
There are two types of packet delays -- one-way delay and two-way
delay (Round Trip Delay).
One-way delay is defined in [RFC2679] as the time elapsed from the
start of transmission of the first bit of a packet by an RBridge
until the reception of the last bit of the packet by the destination
RBridge.
Two-way delay is also referred to as Round Trip Delay and is defined
similar to [RFC2681]; i.e. the time elapsed from the start of
transmission of the first bit of a packet from RB1, receipt of the
packet at RB2, RB2 sending a response packet back to RB1 and RB1
receiving the last bit of that response packet.
OAM SHOULD provide functions to measure two-way delay between two
RBridges.
OAM MAY provide functions to measure one-way delay between two
RBridges for a specified flow.
OAM MAY provide functions to measure one-way delay between two
RBridges for a specified flow over a specific section.
4.7. ECMP Utilization
OAM MAY provide functionality to monitor the effectiveness of per-
hop ECMP hashing. For example, individual RBridges could maintain
counters that show how packets are being distributed across equal
cost next hops for a specified destination RBridge or RBridges as a
result of ECMP hashing.
4.8. Security and Operational considerations
Methods MUST be provided to protect against exploitation of OAM
framework for security and denial of service attacks.
Methods SHOULD be provided to prevent OAM messages causing
congestion in the networks. Periodically generated messages with
high frequencies may lead to congestion, hence methods such as
shaping or rate limiting SHOULD be utilized.
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4.9. Fault Indications
The term Fault refers to an inability to perform a required action,
e.g., an unsuccessful attempt to deliver a packet [OAMOVER]. The
unsuccessful attempt may be due to Hop Count expiry, invalid
nickname, etc.
OAM MUST provide a Fault Indication framework to notify faults to
the ingress RBRidge of the packet or other interested parties (such
as syslog servers).
OAM MUST provide functions to selectively enable or disable
different types of Fault Indications.
4.10. Defect Indications
[OAMOVER] defines "The term Defect refers to an interruption in the
normal operation, such as a consecutive period of time where no
packets are delivered successfully."
OAM SHOULD provide a framework for Defect Detection and Indication.
OAM implementations that provide Defect Indication SHOULD provide
methods to selectively enable or disable Defect Detection per defect
type.
OAM implementations that provide Defect Indication SHOULD provide
methods to configure Defect Detection thresholds per different types
of defects.
OAM implementations that provide Defect Indication facilities SHOULD
provide methods to log defect indications to a locally defined
archive such as log buffer or SNMP traps.
OAM implementations that provide Defect Indication facilities SHOULD
provide a Remote Defect Indication framework that facilitates
notifying the originator/owner of the flow experiencing the defect,
which is the ingress RBridge.
Remote Defect Indication MAY be either in-band or out-of-band.
4.11. Live Traffic monitoring
OAM implementations MAY provide methods to utilize live traffic for
troubleshooting and performance monitoring.
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Implementations MAY leverage Data Driven CFM [8021Q] or IPFIX
[RFC5101] for the purpose of performance monitoring.
5. Security Considerations
Security Requirements are specified in section 4.8. For general
TRILL security considerations please refer to [RFC6325]
6. IANA Considerations
None
7. References
7.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
7.2. Informative References
[RFC6325] Perlman, R., et.al., "Routing Bridges (RBridges): Base
Protocol Specification", RFC 6325, July 2011.
[RFC5101] Claise, B., "Specification of the IP Flow Information
Export (IPFIX) Protocol for the Exchange of IP Traffic
Flow Information", RFC5101, January 2008.
[RFC2680] Almes, G., et.al. "A One-way Packet Loss Metric for IPPM",
RFC 2680, September 1999.
[RFC2679] Almes, G., et.al. "A One-way Delay Metric for IPPM", RFC
2679, September 1999.
[RFC2681] Almes, G., et.al. "A Round-trip Delay Metric for IPPM",
RFC 2681, September 1999.
[RFC6291] Anderson, L., et.al. "Guidelines for the Use of the "OAM"
Acronym in the IETF", RFC 6291, June 2011.
[8021ag] IEEE, "Virtual Bridged Local Area Networks Amendment 5:
Connectivity Fault Management", 802.1ag, 2007.
[8021Q] IEEE, "Media Access Control (MAC) Bridges and Virtual
Bridged Local Area Networks", IEEE Std 802.1Q-2011,
August, 2011.
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[RFC4377] Nadeau, T., et.al. "Operations and Management (OAM)
Requirements for Multi-protocol Label Switched
(MPLS)Networks", RFC 4377, February 2006.
[OAMOVER] Mizrahi, T, et.al., "An Overview of Operations,
Administration, and Maintenance (OAM) Mechanisms", draft-
ietf-opsawg-oam-overview-06, Work in Progress, March 2012.
[RFC5860] Vigoureux, M., et.al., "Requirements for Operations,
Administration and Maintenance (OAM) in MPLS Transport
Networks", RFC5860, May 2010.
8. Acknowledgments
Special acknowledgments to IEEE 802.1 chair, Tony Jeffree for
allowing us to solicit comments from IEEE 802.1 group. Also
recognized are the comments received from IEEE group, Ayal Lior and
others.
This document was prepared using 2-Word-v2.0.template.dot.
9. Contributing Authors
Tissa Senevirathne
CISCO Systems
375 East Tasman Drive
San Jose, CA 95134
USA.
Phone: +1-408-853-2291
Email: tsenevir@cisco.com
David Bond
IBM
2051 Mission College Blvd
Santa Clara, CA 95054
USA
Phone: +1-603-339-7575
Email: mokon@mokon.net
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Sam Aldrin
Huawei Technologies
2330 Central Express Way
Santa Clara, CA 95951
USA
Email: aldrin.ietf@gmail.com
Yizhou Li
Huawei Technologies
101 Software Avenue,
Nanjing 210012
China
Phone: +86-25-56625375
Email: liyizhou@huawei.com
Rohit Watve
CISCO Systems
375 East Tasman Drive
San Jose, CA 95134
USA.
Phone: +1-408-424-2091
Email: rwatve@cisco.com
Thomas Narten
IBM Corporation
3039 Cornwallis Avenue,
PO Box 12195
Research Triangle Park, NC 27709
USA
Email:narten@us.ibm.com
Donald Eastlake
Huawei Technologies
155 Beaver Street,
Milford, MAC 01757
USA.
Email: d3e3e3@gmail.com
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Anoop Ghanwani
DELL
350 Holger Way
San Jose, CA 95134
USA.
Phone: +1-408-571-3500
Email: Anoop@alumni.duke.edu
Jon Hudson
Brocade
120 Holger Way
San Jose, CA 95134
USA.
Email: jon.hudson@gmail.com
Naveen Nimmu
Broadcom
9th Floor, Building no 9, Raheja Mind space
Hi-Tec City, Madhapur,
Hyderabad - 500 081, INDIA
Phone: +1-408-218-8893
Email: naveen@broadcom.com
Radia Perlman
Intel Labs
2700 156th Ave NE, Suite 300,
Bellevue, WA 98007
USA.
Phone: +1-425-881-4824
Email: radia.perlman@intel.com
Tal Mizrahi
Marvell
6 Hamada St.
Yokneam, 20692 Israel
Email: talmi@marvell.com
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