Internet DRAFT - draft-ietf-ccamp-rsvp-te-sdh-otn-oam-ext
draft-ietf-ccamp-rsvp-te-sdh-otn-oam-ext
Network Working Group A. Kern
Internet-Draft A. Takacs
Intended status: Standards Track Ericsson
Expires: May 14, 2014 November 10, 2013
GMPLS RSVP-TE Extensions for SONET/SDH and OTN OAM Configuration
draft-ietf-ccamp-rsvp-te-sdh-otn-oam-ext-06
Abstract
GMPLS has been extended to support connection establishment in both
SONET/SDH and OTN networks. However support for the configuration of
the OAM functions is not specified. Both SONET/SDH and OTN implement
OAM functions to monitor the transported signals. This document
defines extensions to RSVP-TE for SONET/SDH and OTN OAM configuration
based on the OAM Configuration Framework defined in a separate
document. This document supports, but does not modify, ITU-T OAM
mechanisms.
Requirements Language
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].
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 http://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 May 14, 2014.
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Copyright Notice
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document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Overview of SONET/SDH and OTN OAM related functions . . . . . 3
2.1. Continuity supervision . . . . . . . . . . . . . . . . . 3
2.2. Connectivity supervision . . . . . . . . . . . . . . . . 3
2.2.1. SONET/SDH . . . . . . . . . . . . . . . . . . . . . . 4
2.2.2. OTN . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.3. Signal quality supervision . . . . . . . . . . . . . . . 4
2.3.1. SONET/SDH . . . . . . . . . . . . . . . . . . . . . . 4
2.3.2. OTN . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.4. Delay measurement . . . . . . . . . . . . . . . . . . . . 5
3. RSVP-TE signaling extensions . . . . . . . . . . . . . . . . 5
3.1. Operation overview . . . . . . . . . . . . . . . . . . . 5
3.1.1. Continuity Check supervision . . . . . . . . . . . . 6
3.1.2. Connectivity Monitoring supervision . . . . . . . . . 6
3.1.2.1. SDH/SONET . . . . . . . . . . . . . . . . . . . . 6
3.1.2.2. OTN . . . . . . . . . . . . . . . . . . . . . . . 6
3.1.3. Signal quality supervision . . . . . . . . . . . . . 7
3.2. Signaling support of Virtual Concatenation Groups (VCG) . 8
3.3. OAM types and functions . . . . . . . . . . . . . . . . . 8
3.4. SONET/SDH OAM Configuration Sub-TLV . . . . . . . . . . . 9
3.5. OTN OAM Configuration Sub-TLV . . . . . . . . . . . . . . 9
3.6. SDH TTI Configuration Sub-TLV . . . . . . . . . . . . . . 9
3.7. OTN TTI Configuration Sub-TLV . . . . . . . . . . . . . . 10
3.8. Degraded Signal Thresholds Sub-TLV . . . . . . . . . . . 12
4. Error handling . . . . . . . . . . . . . . . . . . . . . . . 13
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
6. Security Considerations . . . . . . . . . . . . . . . . . . . 14
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
8.1. Normative References . . . . . . . . . . . . . . . . . . 15
8.2. Informative References . . . . . . . . . . . . . . . . . 15
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Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16
1. Introduction
Both SONET/SDH and OTN implement OAM functions to monitor the
transported signals. Supervision functions include continuity,
connectivity, signal quality, alignment and payload supervision. The
ITU-T G.806 [G.806] recommendation defines the generic framework of
the supervision functions, which are then further specified for SONET
/SDH and OTN in technology specific documents.
GMPLS has been extended to support connection establishment in SONET/
SDH [RFC4606], and in OTN [RFC4328] [RFC6344] networks. These
documents however do not support the configuration of the respective
OAM supervision functions.
[I-D.ietf-ccamp-oam-configuration-fwk] defines a technology-agnostic
framework for GMPLS to support the establishment and configuration of
the pro-active OAM functions of signaled connections. The properties
of the OAM functions are exchanged during connection establishment
and may be modified during the life of the connection. The
technology specific parameters to be exchanged are to be described in
accompanying documents. This document defines the extensions for
SONET/SDH and OTN OAM configuration for end-to-end monitoring.
2. Overview of SONET/SDH and OTN OAM related functions
SONET/SDH [G.707] and OTN [G.709] provide a variety of supervision
functions. Among these functions we consider continuity,
connectivity and signal quality supervision functions, as these are
the candidates for GMPLS based configuration. We also consider delay
measurement functionality for OTN. The reader should refer to the
ITU-T documents for additional information. Familiarity with GMPLS,
SONET/SDH and OTN terminology is assumed.
2.1. Continuity supervision
Continuity supervision provides methods for monitoring the health of
a connection (trail).
2.2. Connectivity supervision
The connectivity supervision function provides a method to detect
misconnections. The detection procedure is based on a Trace Trail
Identifier (TTI) known by both endpoints. The TTI is included by the
source node as an overhead signal for each connection. The receiver
node then compares the received TTI with the expected value and
determines if a mis-connection occurred.
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2.2.1. SONET/SDH
In case of SONET/SDH, connectivity supervision is implemented in the
Regeneration Section (RS) and in the lower and higher order path
layers (LOVC and HOVC). In all layers the TTI encodes only the
Access Point Identifier (API) of the source node. In the various
layers, the lengths of these TTIs are different. In RS, the TTI
(encoded in J0 byte) is either 1 or 16 bytes long. In higher order
paths the TTI (encoded in J1), is either 16 or 64 bytes long. In
lower order paths, the TTI is transmitted in the J2 byte and is 16
bytes long.
2.2.2. OTN
In case of OTN, connectivity supervision is supported by the OTUk and
ODUk digital hierarchy layers. In both layers, the length of the TTI
is 64 bytes, but only the first 32 bytes are considered for
connectivity supervision. This first part is further divided into a
Source Access Point Identifier (SAPI) and a Destination Access Point
Identifier (DAPI). Connectivity supervision may consider either the
SAPI or DAPI only or both. The structure of the SAPI and DAPI is
specified in [G.709].
2.3. Signal quality supervision
The quality of the transmitted signal is monitored as a ratio of bad
frames. If the number of such frames reaches a threshold, a defect
state is declared. To detect the correctness of the frames, an Error
Detection Code (EDC), such as Bit Interleaved Parity (BIP), is used.
The distribution of the errors is assumed to follow either Poisson or
a bursty distribution. For Poisson distribution, an EDC violation
ratio is defined as the threshold; while for the bursty model, the
threshold is defined as a number of consecutive 1-second time
intervals in which the EDC violation exceeds a predefined ratio. In
case of Poisson error distribution, two defect state levels are
defined: the Excessive Error and Degraded Signal defect. In the case
of the bursty model, only the Degraded Signal defect level is
considered.
2.3.1. SONET/SDH
SONET/SDH supports both Excessive Error and Degraded Signal defect
levels and supports both Poisson and bursty error distribution
models. These signal quality parameters are configured for the
Multiplexing Section (MS) and the LOVC and HOVC path layers.
2.3.2. OTN
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For OTN, in the digital transport layers (OTUk and ODUk), only the
bursty error distribution model with the Degraded Signal defect level
is supported. Two parameters are defined: Ratio of the bad frames in
a one second interval (0% to 100% or 0 to number of frames per
1-second interval) and Number of consecutive intervals (between 2 and
10). Signal quality supervision in the optical transport layers is
not specified by [G.798], it is indicated to be for further study.
2.4. Delay measurement
[G.709] introduced a tool for measuring round-trip delay of a
bidirectional ODU path or tandem connection. For implementing delay
measurement, a one-bit delay measurement (DM) signal is defined in
the ODUk header. That signal bit is a constant value (either 0 or
1). One endpoint initiates a delay measurement by inverting the bit
emitted in the DM signal. The remote endpoint loops back the DM
signal; therefore, the delay measurement initiating node will receive
the inverted signal from the remote endpoint. This way the
initiating endpoint will determine the round trip delay.
3. RSVP-TE signaling extensions
3.1. Operation overview
RFC 4328, RFC 4606 and RFC6344 defined the GMPLS RSVP-TE extensions
necessary to manage SONET/SDH and OTN optical and digital hierarchy
connections. The monitoring functions associated to these
connections MAY be configured when configuring the connections.
The LSP Attribute Flag "OAM MEP entities desired"
[I-D.ietf-ccamp-oam-configuration-fwk] MUST be used to signal that
the monitoring functions at the endpoints MUST be established. The
"OAM MIP entities desired" flag MUST be set to 0 and MUST be ignored.
To configure OAM parameters, the OAM Configuration TLV MAY be
included in the LSP_ATTRIBUTES object. The TLV identifies which OAM
technology ("OAM Type" field) to be used as well as which OAM
functions are to be enabled (OAM Function Flags Sub-TLV). For SONET/
SDH and OTN, the "Continuity Check" and "Connectivity Verification"
flags control the Continuity and Connectivity supervision functions,
while the "Performance Monitoring/Loss" flag enables the Signal
Quality supervision function.
The recent revision of OTN [G.709] introduced delay measurement
capability for paths. A node MAY enable delay measurement by setting
the "Performance Monitoring/Delay" flag. By setting that flag, the
node also indicates that it will initiate the delay measurement;
therefore, the remote endpoint node SHOULD NOT initiate delay
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measurement over the configured connection. Equipment designed to
earlier versions of G709 MUST clear the "Performance Monitoring/Loss"
flag and upon receiving an OAM configuration message with
"Performance Monitoring/Delay" flag set MUST generate "OAM Problem/
Unsupported OAM Function" error. The "Performance Monitoring/Delay"
flag MUST be cleared for SONET/SDH as it is not supported by SONET/
SDH.
For additional details, the appropriate technology specific sub-TLV
MAY be carried in the OAM Configuration TLV.
3.1.1. Continuity Check supervision
In case of both SONET/SDN and OTN technologies, setting up the
continuity supervision function for a connection does not need
further configuration besides enabling it. Therefore, by setting the
"Connectivity Monitoring" Flag of OAM Function implicitly enables the
continuity supervision function as well.
3.1.2. Connectivity Monitoring supervision
3.1.2.1. SDH/SONET
[G.707] defines three TTI overhead bytes (signals) for connectivity
supervision: the J0 byte in RS layer, the J1 byte in the HOVC layer
and the J2 byte in the LOVC layer. The source node transmits the TTI
and the destination node matches it with the expected one. When the
destination detects mismatch, a defect state will be declared.
Since these bytes encode a TTI identifier defined for the source
node, different stream will be emitted in the upstream and downstream
directions for bidirectional connections. During the configuration
the downstream (destination) node has to be configured with the TTI
value to be expected in the downstream direction and the TTI value to
be emitted in the upstream direction. Therefore, the SONET/SDH OAM
Configuration TLV carries two Connectivity Supervision TLVs.
3.1.2.2. OTN
[G.709] defines a 64 byte long TTI format, where the first 32 bytes
have a generic structure: a zero byte, a 15 bytes long SAPI, a second
zero byte and finally the 15 bytes long DAPI format.
For a unidirectional connection, a single Connection Supervision TLV
encodes elements of the TTI to be emitted. This TLV also specifies
which parts of the TTI are compared to the expected values (only
SAPI, only DAPI, both SAPI and DAPI).
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In case of a bidirectional connection an endpoint can use a common
API value for SAPI (for transmitted signal) and DAPI (for received
signal). (See Figure 1.) The TTI values used in downstream and
upstream directions are derived from the two API values: the
downstream TTI will have the form of [0, API_a, 0, API_z] while the
upstream TTI will use the form of [0, API_z, 0 API_a].
Ingress Node Egress Node
( API_a ) TTI_upstream = [0, API_z, 0, API_a ] ( API_z )
| Rx port | -- < -- < -- < -- < -- < -- < -- < -- < -- | Tx Port |
| Tx port | -- > -- > -- > -- > -- > -- > -- > -- > -- | Rx Port |
TTI_downstream = [0, API_a, 0, API_z ]
Figure 1: TTI construction when a single API identifies the receiver
and transmitter interfaces
Then, a single Connectivity Supervision TLV is defined. The SAPI
field carries the API of the ingress node (API_a) that initiates the
signaling, while the DAPI carries the API of the egress node (API_z).
On the other hand, it is possible that the endpoints use different
values as SAPI and DAPI to identify the transmitter and receiver
ports of a bidirectional connection (See Figure 2). In this case the
TTIs to be used in the two directions are independent, thus, they
must be explicitly configured. Therefore, two Connectivity
Supervision TLVs are added to the OTN OAM Configuration TLV. Each
TLV encodes whether it defines the downstream or the upstream TTI.
Ingress Node Egress Node
( API_a1 ) TTI_upstream = [0, API_z1, 0, API_a1 ] ( API_z1 )
| Rx port | -- < -- < -- < -- < -- < -- < -- < -- < -- | Tx Port |
| Tx port | -- > -- > -- > -- > -- > -- > -- > -- > -- | Rx Port |
( API_a2 ) TTI_downstream = [0, API_a2, 0, API_z2 ] ( API_z2 )
Figure 2: TTI construction when dedicated APIs identify the receiver
and transmitter interfaces
3.1.3. Signal quality supervision
Signal quality supervision function is implemented in the MS, HOVC,
LOVC layers of SONET/SDH. All three layers support exceeded error
level with Poisson error distribution model and degraded signal
defect level with both of the Poisson and bursty error distribution
models. Dedicated Signal quality supervision TLVs encode each level,
therefore when the "Performance Monitoring/Loss" flag is set; several
such TLVs MAY be added to the SONET/SDH OAM Configuration TLV. If a
configuration TLV for a particular level is missing, the default
parameters for that level SHOULD be applied.
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OTN supports only Degraded Signal defect with bursty error model in
OTUk and ODUk layers. Thus, the only parameters to be encoded are:
the threshold for bad frames in a 1-second interval and the number of
consecutive 1-second intervals with excessive bad frames.
Furthermore, as only one level is allowed, a single Signal quality
supervision TLV MAY be added to the OTN OAM Configuration TLV.
3.2. Signaling support of Virtual Concatenation Groups (VCG)
A capability of both SONET/SDH and OTN is the support of virtual
concatenation. This inverse multiplexing method uses multiplicity of
parallel individual signals. The supervision function parameters of
these basic signals can be different.
[RFC6344] describes GMPLS signaling capabilities to support virtual
concatenation. A Virtual Concatenated Group (VCG) is constructed
from several individual data plane signals. The co-routed signals of
a VCG may be provisioned together using a single RSVP-TE session (co-
signaled). As different OAM configuration may be applied to each of
these individual signals, the OAM configuration extension is applied
as follows.
We assume that the same OAM type and the same set of OAM functions
apply to each individual signal of the VCG. A single OAM
Configuration TLV MUST be carried in the LSP_ATTRIBUTES Object, while
multiple instances of technology specific OAM configuration sub-TLVs
MAY be added: one instance per individual signal. The order of these
TLVs references the logical order of the individual signals (as they
are listed in the Label Object).
[RFC6344] allows extension/pruning of a VCG. To achieve it, the
traffic descriptor, which encodes how the VCG is structured, in the
RSVP-TE session is updated. If the VCG is updated, the contents of
the OAM Configuration TLV MUST be updated accordingly.
3.3. OAM types and functions
This document defines two new code points for the "OAM Type" field of
the OAM Configuration TLV, defined in
[I-D.ietf-ccamp-oam-configuration-fwk]: SONET/SDH OAM and OTN Digital
Hierarchy OAM.
The "OAM Function Flags Sub-TLV" is defined in
[I-D.ietf-ccamp-oam-configuration-fwk]. SONET/SDH and OTN
supervision functions are defined in this document for the following
flags: "Continuity Check", "Connectivity Verification", "Performance
Monitoring/Loss" and "Performance Monitoring/Delay".
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3.4. SONET/SDH OAM Configuration Sub-TLV
SONET/SDH OAM Configuration Sub-TLV is defined to encode the
parameters of continuity, connectivity and signal quality supervision
functions for SONET/SDH networks.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type (34) (IANA) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ sub TLVs ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: indicates a new type: the SONET/SDH OAM Configuration TLV (IANA
to define).
Length: indicates the total length including sub-TLVs
3.5. OTN OAM Configuration Sub-TLV
OTN OAM Configuration TLV is defined to encode the parameters of
continuity, connectivity and signal quality supervision functions for
OTN.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type (35) (IANA) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ sub TLVs ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: indicates a new type: the OTN OAM Configuration TLV (IANA to
define).
Length: indicates the total length including sub-TLVs
3.6. SDH TTI Configuration Sub-TLV
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This sub-TLV is carried in the SONET/SDH OAM Configuration Sub-TLV,
if the Connectivity Verification OAM Function Flag is set. In each
supporting layer, the TTI identifies the source interface (SAPI);
however, the length of this identifier varies layer-by-layer (see
Section 2.2.1). Therefore, a generic TLV is defined supporting
various TTI lengths.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type (IANA) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A|U| Reserved | TTI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ TTI cont ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Flag "A", when set enables the AIS insertion when detecting a TTI
mismatch.
Flag "U" encodes if the TTI refers to the downstream node's source
TTI (U=0) or the upstream node's TTI (U=1) (expected TTI).
The TTI field carries the TTI to be transmitted by the source node
and to be expected by the sink. The TLV is padded to 4 bytes.
If the specified length and format of the TTI carried in this TLV is
not supported by the referenced SONET/SDH layer, an error must be
generated: "OAM Problem/TTI Length Mismatch".
3.7. OTN TTI Configuration Sub-TLV
This sub-TLV is carried in the OTN OAM Configuration Sub-TLV, if the
Connectivity Verification OAM Function Flag is set.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type (IANA) | Length = 32 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A|S|D|APP| Reserved | SAPI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SAPI cont |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SAPI cont |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SAPI cont |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SAPI | DAPI |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DAPI cont |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DAPI cont |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DAPI cont |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Three control flags are defined. Flag "A" indicates that AIS
insertion when detecting a TTI mismatch (failing the connectivity
verification) is required (A=1) or not (A=0). The next two flags
define which parts of the received TTI are compared to the expected
one. If flag "S" is set, the TTI bytes 1 to 15 are matched to the
expected SAPI value. If the flag "D" is set, the TTI bytes 17 to 31
are matched to the expected DAPI value. If both "S" and "D" are set,
both parts of TTI are compared to SAPI and DAPI values. Setting both
"S" and "D" bits to 0 is invalid, and if encountered, an error must
be generated: "OAM Problem/Invalid CC/CV configuration".
The next two bits "APP" encode the applicability of the TTI
configuration and the following code points are defined:
0 - Single TTI configuration: the TTI configuration is done
according only to this TLV and no further TTI configuration TLVs
are expected. This code point is used for unidirectional
connections and for bidirectional connections with common APIs
(See Figure 1)
1 - Downstream TTI for double TTI configuration: the current TLV
instructs the configuration of the TTI to be used in downstream
direction (See Figure 2).
2 - Upstream TTI for double TTI configuration: the current TLV
instructs the configuration of the TTI to be used in upstream
direction (See Figure 2).
3 - Invalid.
If the APP is set to 1 and the next or the previous sub-TLV is not an
OTN TTI Configuration TLV with APP code point 2, then an error must
be generated "OAM Problem/Invalid OTN TTI Configuration - Missing
Upstream TTI configuration".
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If the APP is set to 2 and the next or the previous sub-TLV is not an
OTN TTI Configuration TLV with APP code point 1, then an error must
be generated "OAM Problem/Invalid OTN TTI Configuration - Missing
Downstream TTI configuration".
If the APP is set to either 1 or 2 and the unidirectional LSP is
signaled (no UPSTREAM_LABEL is added to the message) or the APP is
set to 3, an error must be generated "OAM Problem/Invalid OTN TTI
Configuration - Invalid applicability code".
3.8. Degraded Signal Thresholds Sub-TLV
The Degraded Signal Thresholds Sub-TLV instructs the configuration of
the signal quality supervision function. This sub-TLV is applicable
in both SONET/SDH and OTN cases. This sub-TLV can be carried in both
the SONET/SDH OAM Configuration Sub-TLV or OTN OAM Configuration Sub-
TLV, if the PerformanceMonitoring/Loss OAM Function Flag is set.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type (IANA) | Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|B|L| Reserved | DEG_THR | DEG_M |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Two flags are defined to encode the signal quality measurement. The
bit "B" encodes if distribution of errors is either Poisson (B=0) or
Bursty (B=1). In case of Poisson distribution of errors, two levels
of defects are defined and encoded with bit "L": excessive error
(L=0) and degraded signal (L=1). Since in case of Bursty
distribution of errors, only degraded signal defect is to be
detected, therefore, in this latter case (B=1), the "L" bit must be
set. Otherwise, an error must be generated: "OAM Problem/Invalid
Performance Monitoring/Loss configuration".
The field "DEG_THR" defines the threshold for the bad frames (BIP-8
violations) in both Poisson and bursty distributions of errors. In
the first case (B=0), this field encodes the quotient of the
threshold 10e-X. The possible values for excessive error are 3,4 and
5, while for degraded signal defect, the values are 6,7,8 and 9.
In the second case (B=1), it encodes the ratio of the bad frames in a
1-second period and can be set between 0 and 100, interpreted as
ratios in percentage.
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The field "DEG_M" defines the monitoring time-frame in 1 second
periods assuming bursty distribution of errors. The valid values are
2 to 10 periods.
4. Error handling
In addition to error values specified in
[I-D.ietf-ccamp-oam-configuration-fwk] this document defines the
following values for the "OAM Problem" Error Code.
If in the OTN TTI Configuration Sub-TLV both the "S" and "D" bits are
set to 0, an error must be generated: "OAM Problem/Invalid CC/CV
Configuration".
If the specified length and format of the TTI carried in the SONET/
SDH TTI Configuration Sub-TLV is not supported by the SONET/SDH
layer, an error must be generated: "OAM Problem/TTI Length Mismatch"
If in the OTN TTI Configuration Sub-TLV the "APP" field is set to 1
and the next or the previous sub-TLV is not an OTN TTI Configuration
TLV with "APP" code point 2, then an error must be generated "OAM
Problem/Invalid OTN TTI Configuration - Missing Upstream TTI
Configuration".
If in the OTN TTI Configuration Sub-TLV the "APP" field is set to 2
and the next or the previous sub-TLV is not an OTN TTI Configuration
TLV with APP code point 1, then an error must be generated "OAM
Problem/Invalid OTN TTI Configuration - Missing Downstream TTI
Configuration".
If in the OTN TTI Configuration Sub-TLV the "APP" field is set to
either 1 or 2 and an unidirectional LSP is signaled (no
UPSTREAM_LABEL) or the "APP" field is set to 3, an error must be
generated "OAM Problem/Invalid OTN TTI Configuration - Invalid
Applicability Code".
If flag "B" in Degraded Signal Thresholds Sub-TLV is set to 1 and
flag "L" in the same sub-TLV is set to 0, an error must be generated
"OAM Problem/Invalid Performance Monitoring/Loss Configuration".
5. IANA Considerations
This document specifies two new sub-TLVs to be carried in the OAM
Configuration TLV in the LSP_ATTRIBUTES or LSP_REQUIRED_ATTRIBUTES
Objects in Path and Resv messages. The document defines two new
values of the "OAM Type" field of the OAM Configuration TLV. IANA is
requested to make the following assignments in the RSVP-TE OAM
Configuration Registry.
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RSVP-TE OAM Configuration Registry
OAM Type Description
------------------- -----------------------------------
3 SONET/SDH OAM
4 OTN Digital Hierarchy OAM
Sub-TLV Type Description
------------------- -----------------------------------
34 SONET/SDH OAM Configuration Sub-TLV
35 OTN OAM Configuration Sub-TLV
IANA is requested to maintain the SONET/SDH and OTN TLV Type space in
the "RSVP-TE OAM Configuration Registry" for the sub-TLV types
carried in the SONET/SDH and OTN OAM Configuration Sub-TLVs. This
document defines the following types.
SONET/SDH and OTN TLV Type Description
-------------------------- --------------------------------
0 Reserved
1 SONET/SDH TTI Configuration Sub-TLV
2 OTN TTI Configuration Sub-TLV
3 Degraded Signal Thresholds Sub-TLV
IANA is requested to assigne the following error values under the
"OAM Problem" error code: "TTI Length Mismatch", "Invalid CC/CV
Configuration", "Invalid OTN TTI Configuration - Missing Upstream TTI
Configuration", "Invalid OTN TTI Configuration - Missing Downstream
TTI Configuration", "Invalid OTN TTI Configuration - Invalid
Applicability Code", "Invalid Performance Monitoring/Loss
Configuration".
6. Security Considerations
Security aspects are addressed in the OAM configuration framework
document [I-D.ietf-ccamp-oam-configuration-fwk]. This document does
not introduce any additional security issues to those discussed in
[I-D.ietf-ccamp-oam-configuration-fwk] and the SONET/SDH and OTN
technology-specific RFCs.
7. Acknowledgements
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The authors would like to thank Francesco Fondelli for his useful
comments.
8. References
8.1. Normative References
[I-D.ietf-ccamp-oam-configuration-fwk]
Takacs, A., Fedyk, D., and H. Jia, "GMPLS RSVP-TE
extensions for OAM Configuration", draft-ietf-ccamp-oam-
configuration-fwk-10 (work in progress), June 2013.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
8.2. Informative References
[G.707] International Telecommunications Union, "Network node
interface for the synchronous digital hierarchy (SDH)",
ITU-T Recommendation G.707, 2007.
[G.709] International Telecommunications Union, "Interfaces for
the Optical Transport Network (OTN)", ITU-T Recommendation
G.709, 2012.
[G.798] International Telecommunications Union, "Characteristics
of optical transport network hierarchy equipment
functional blocks ", ITU-T Recommendation G.798, 2006.
[G.806] International Telecommunications Union, "Characteristics
of transport equipment - Description methodology and
generic functionality", ITU-T Recommendation G.806, 2009.
[RFC4328] Papadimitriou, D., "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Extensions for G.709 Optical
Transport Networks Control", RFC 4328, January 2006.
[RFC4606] Mannie, E. and D. Papadimitriou, "Generalized Multi-
Protocol Label Switching (GMPLS) Extensions for
Synchronous Optical Network (SONET) and Synchronous
Digital Hierarchy (SDH) Control", RFC 4606, August 2006.
[RFC6344] Bernstein, G., Caviglia, D., Rabbat, R., and H. van
Helvoort, "Operating Virtual Concatenation (VCAT) and the
Link Capacity Adjustment Scheme (LCAS) with Generalized
Multi-Protocol Label Switching (GMPLS)", RFC 6344, August
2011.
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Authors' Addresses
Andras Kern
Ericsson
Laborc u. 1.
Budapest 1037
Hungary
Email: andras.kern@ericsson.com
Attila Takacs
Ericsson
Laborc u. 1.
Budapest 1037
Hungary
Email: attila.takacs@ericsson.com
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