Internet DRAFT - draft-tissa-trill-oam-req
draft-tissa-trill-oam-req
TRILL Working Group Tissa Senevirathne
Internet Draft CISCO
Intended status: Informational David Bond
IBM
Sam Aldrin
Yizhou Li
Huawei
Rohit Watve
CISCO
Anoop Ghanwani
DELL
Jon Hudson
Brocade
Naveen Nimmu
Broadcom
Radia Perlman
Intel
Tal Mizrahi
Marvell
June 29, 2012
Expires: December 2012
Requirements for Operations, Administration and Maintenance (OAM) in
TRILL
draft-tissa-trill-oam-req-02.txt
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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. Also presented in this document is the proposed frame
structure for TRILL OAM messages.
Table of Contents
1. Introduction...................................................3
1.1. Contributors..............................................4
2. Conventions used in this document..............................4
3. Terminology....................................................4
4. OAM Requirements...............................................5
4.1. Data Plane................................................5
4.2. Connectivity Verification.................................6
4.2.1. Unicast..............................................6
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4.2.2. Multicast............................................6
4.3. Continuity Check..........................................6
4.4. Path Tracing..............................................7
4.5. General Requirements......................................7
4.6. Performance Monitoring....................................8
4.6.1. Packet Loss..........................................8
4.6.2. Packet Delay.........................................9
4.7. ECMP Utilization..........................................9
4.8. Security and Operational considerations...................9
4.9. Fault Indications........................................10
4.10. Defect Indications......................................10
4.11. Live Traffic monitoring.................................11
5. General Format of TRILL OAM Messages..........................11
5.1. Requirements of OAM Message channel......................12
6. Security Considerations.......................................12
7. IANA Considerations...........................................12
8. References....................................................13
8.1. Normative References.....................................13
8.2. Informative References...................................13
9. Acknowledgments...............................................14
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. Also the
proposed format for OAM frames is presented.
It is assumed that the readers are familiar with the OAM concepts
and terminologies defined in other OAM standards such as [802.1ag],
[RFC5860]. This document does not attempt to redefine the terms and
concepts specified elsewhere.
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1.1. Contributors
The following members were part of the design team that produced
this document. Their names are listed below in alphabetical order.
Anoop Ghanwani, David Bond, Donald Eastlake 3rd, Jon Hudson, Naveen
Nimmu, Radia Perlman, Rohit Watve, Sam Aldrin, Shivakumar Sundaram,
Tal Mizrahi, Thomas Narten, Tissa Senevirathne, Yizhou Li.
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
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 Least Cost Paths: The term "all least cost paths" refers to all
potentially available least cost paths from a given source to a
specified destination RBridge as determined by the TRILL network
topology learned from IS-IS. ECMP: Equal Cost Multi Path.
Connectivity: The term connectivity indicates reachability between
an arbitrary RBridge RB1 and any other RBridge RB2. The specific
path can be either explicit (e.g. specific flow) or unspecified.
Unspecified means taking whatever the path connectivity verification
message happen to take.
Continuity Verification: Continuity Verification refers to proactive
verification of Connectivity between two RBridges at periodic
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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.
4. OAM Requirements
4.1. Data Plane
OAM frames, utilized for connectivity verification, continuity
checks, performance measurements, etc., MUST follow the same path as
the specified flow.
OAM frames, utilized for connectivity verification, continuity
checks, performance measurements, etc., when a specific flow is not
specified MUST follow whatever the path TRILL choose based on
current topology, per-hop forwarding behavior and default flow
entropy.
RBridges MUST have the ability to identify OAM frames destined for
them or which require processing by the OAM plane from normal data
frames.
RBridges MUST have the ability to differentiate between OAM frames
and data frames experiencing errors.
TRILL OAM frames MUST be confined to the TRILL domain and MUST NOT
be forwarded out of the TRILL domain. E.g. they must not be sent as
native frames on an end station service enabled port
OAM MUST have the capability to provide services for both IP and
non-IP flows.
OAM MUST be able to function in IP and non-IP infrastructure.
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4.2. Connectivity Verification
4.2.1. Unicast
OAM MUST have the ability to verify connectivity from an arbitrary
RBridge RB1 to any other RBridge RB2.
OAM MUST have the ability to verify connectivity from an arbitrary
RBridge RB1 to any other RBridge RB2 for a specific 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.
OAM MUST have the ability to invoke the above functions on-demand.
4.2.2. Multicast
OAM MUST have the ability to verify connectivity, from an arbitrary
RBridge RB1, to either to 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 to 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.
OAM MUST have the ability to invoke the above functions on-demand.
4.3. Continuity Check
[RFC5860] defines Continuity Check as the ability of end points to
monitor liveliness of a path or a section of a path [RFC5860]. We
use similar semantics in this document where end points are the
ingress or egress RBridges.
OAM MUST provide functions that allow any arbitrary RBridge RB1 to
perform a Continuity Check to any other RBridge.
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OAM MUST provide functions that allow any arbitrary RBridge RB1 to
perform a Continuity Check to any other RBridge for a specified
flow.
OAM SHOULD provide functions that allow any arbitrary RBridge to
perform a Continuity Check to any other RBridge over all available
least cost paths.
OAM SHOULD provide the ability to perform a Continuity Check on
sections of any 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.
OAM implementations SHOULD support at least a minimum frequency of 1
second of Continuity check.
OAM implementations SHOULD support multiple concurrent Continuity
sessions from and/or to the same RBridge.
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 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.
OAM MUST NOT require extensions to or modifications of the TRILL
header.
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OAM MUST provide a single OAM framework for all TRILL OAM functions
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).
Operations of OAM MUST NOT result in errors on end devices.
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, term loss of a packet is used as defined in
[RFC2680] (see Section 2.4 of RFC2680).
NOTE: Term simulated flow below indicates a flow that is generated
by an RBRidge RB1 for OAM purposes. The fields of the simulated flow
may or may not be identical to the actual data. However, simulated
flow is required to follow the intended path.
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.
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An RBridge SHOULD be able to perform the above packet loss
measurement functions either proactively or on-demand.
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 is defined
similar to [RFC2681]; i.e. 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 same RBridge.
OAM SHOULD provide functions to measure two-way delay between two
RBridges for a specified flow.
OAM SHOULD provide functions to measure two-way delay between two
RBridges for a specified flow over a specific section.
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
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high frequencies may lead to congestion, hence methods such as
shaping or rate limiting SHOULD be utilized.
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 flow 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 MUST provide
methods to selectively enable or disable Defect Detection per defect
type.
OAM implementations that provide Defect Indication MUST provide
methods to configure Defect Detection thresholds per different types
of defects.
OAM implementations that provide Defect Indication facilities MUST
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.
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4.11. Live Traffic monitoring
OAM implementations MAY provide methods to utilize live traffic for
troubleshooting and performance monitoring.
Implementations MAY leverage Data Driven CFM [802.1Q] or IPFIX
[RFC5101] for the purpose of performance monitoring.
5. General Format of TRILL OAM Messages
The TRILL forwarding paradigm allows an implementation to select a
path from a set of equal cost paths to forward a packet. Selection
of the path of choice is implementation dependent. However, it is a
common practice to utilize Layer 2 through Layer 4 information in
the inner payload for path selection.
As specified above, OAM Messages are required to follow the exact
path as the data packets.
The proposed frame format for TRILL OAM messages is as follows.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. Outer Header . (variable)
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ TRILL Header + 8 bytes
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. Flow Entropy . 128 bytes
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. OAM Message Channel . Variable
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1 Frame format of OAM Messages
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Outer Header: Media dependent header. For Ethernet this included
Destination MAC, Source MAC, VLAN (optional) and EtherType fields.
TRILL Header: Minimum of 8 bytes when the Extended Header is not
included [RFC6325]
Flow Entropy: This is a 128 byte Fixed size opaque field. The field
MUST be padded with zeros when the flow entropy is less than 128
bytes. Flow entropy emulates the forwarding behavior of the desired
data packets.
OAM Message Channel: This is a variable size section that carries
OAM related information. Reusing existing OAM message definitions
such as [RFC4379] and [802.1ag] will be explored.
5.1. Requirements of OAM Message channel
The OAM Message channel header MUST contain a version number
The OAM Message channel header MUST contain flags that facilitate
hardware level processing. (e.g. indicate this is two-way delay
measurement probe)
The OAM Message channel MUST contain time stamping in fixed
locations to facilitate hardware level performance monitoring. (e.g.
delay measurements).
The OAM Message channel MUST have the ability to be extensible to
include future capabilities without requiring a change to the
version of the message header. (e.g. include TLV structures)
The OAM Message header MUST contain a unique marker that allows for
identifying the presence of the OAM channel. This marker MUST
provide equal or better uniqueness compared to the IP checksum
define in [RFC791]
The OAM Message SHOULD provide methods to include arbitrary data to
test functions such as MTU testing.
6. Security Considerations
Security Requirements are specified in section 4.8.
7. IANA Considerations
<TBD>
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8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[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.
[RFC4377] Nadeau, T., et.al., "Operations and Management (OAM)
Requirements for Multi-Protocol Label Switched (MPLS)
Networks", RFC 4377, February 2006.
8.2. 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 31st , 2011.
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[RFC791] "Internet Protocol", RFC 791, September 1981.
9. 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 Loir and
others.
This document was prepared using 2-Word-v2.0.template.dot.
Authors' Addresses
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
Sam Aldrin
Huawei Technologies
2330 Central Express Way
Santa Clara, CA 95951
USA
Email: aldrin.ietf@gmail.com
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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
Anoop Ghanwani
DELL
350 Holger Way
San Jose, CA 95134
USA.
Phone: +1-408-571-3500
Email: Anoop@duke.alumni.duke.edu
John 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
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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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