Network Working Group E. Mannie

Network Working Group E. Mannie
Request for Comments: 3946 Consultant
Category: Standards Track D. Papadimitriou
Alcatel
October 2004

Generalized Multi-Protocol Label Switching (GMPLS) Extensions for
Synchronous Optical Network (SONET) and
Synchronous Digital Hierarchy (SDH) Control

Status of this Memo

This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.

Copyright Notice

Copyright (C) The Internet Society (2004).

Abstract

This document is a companion to the Generalized Multi-Protocol Label
Switching (GMPLS) signaling. It defines the Synchronous Optical
Network (SONET)/Synchronous Digital Hierarchy (SDH) technology
specific information needed when using GMPLS signaling.

Table of Contents

1. Introduction ................................................. 2
2. SONET and SDH Traffic Parameters ............................. 2
2.1. SONET/SDH Traffic Parameters ........................... 3
2.2. RSVP-TE Details ........................................ 9
2.3. CR-LDP Details ......................................... 9
3. SONET and SDH Labels ......................................... 10
4. Acknowledgments .............................................. 15
5. Security Considerations ...................................... 16
6. IANA Considerations .......................................... 16
7. References ................................................... 16
7.1. Normative References ................................... 16
Appendix 1 - Signal Type Values Extension for VC-3 ............... 18
Annex 1 - Examples ............................................... 18
Contributors ..................................................... 21
Authors' Addresses ............................................... 25
Full Copyright Statement ......................................... 26

Mannie & Papadimitriou Standards Track [Page 1]

RFC 3946 GMPLS Extensions for SONET/SDH Control October 2004

1. Introduction

As described in [RFC3945], Generalized MPLS (GMPLS) extends MPLS from
supporting packet (Packet Switching Capable - PSC) interfaces and
switching to include support of four new classes of interfaces and
switching: Layer-2 Switch Capable (L2SC), Time-Division Multiplex
(TDM), Lambda Switch Capable (LSC) and Fiber-Switch Capable (FSC). A
functional description of the extensions to MPLS signaling needed to
support the new classes of interfaces and switching is provided in
[RFC3471]. [RFC3473] describes RSVP-TE specific formats and
mechanisms needed to support all five classes of interfaces, and CR-
LDP extensions can be found in [RFC3472]. This document presents
details that are specific to Synchronous Optical Network
(SONET)/Synchronous Digital Hierarchy (SDH). Per [RFC3471],
SONET/SDH specific parameters are carried in the signaling protocol
in traffic parameter specific objects.

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].

Moreover, the reader is assumed to be familiar with the terminology
in ANSI [T1.105], ITU-T [G.707] as well as [RFC3471], [RFC3472], and
[RFC3473]. The following abbreviations are used in this document:

DCC: Data Communications Channel.
LOVC: Lower Order Virtual Container
HOVC: Higher Order Virtual Container
MS: Multiplex Section.
MSOH: Multiplex Section overhead.
POH: Path overhead.
RS: Regenerator Section.
RSOH: Regenerator section overhead.
SDH: Synchronous digital hierarchy.
SOH: Section overhead.
SONET: Synchronous Optical Network.
SPE: Synchronous Payload Envelope.
STM(-N): Synchronous Transport Module (-N) (SDH).
STS(-N): Synchronous Transport Signal-Level N (SONET).
VC-n: Virtual Container-n (SDH).
VTn: Virtual Tributary-n (SONET).

2. SONET and SDH Traffic Parameters

This section defines the GMPLS traffic parameters for SONET/SDH. The
protocol specific formats, for the SONET/SDH-specific RSVP-TE objects
and CR-LDP TLVs are described in sections 2.2 and 2.3 respectively.

Mannie & Papadimitriou Standards Track [Page 2]

RFC 3946 GMPLS Extensions for SONET/SDH Control October 2004

These traffic parameters specify indeed a base set of capabilities
for SONET ANSI [T1.105] and SDH ITU-T [G.707] such as concatenation
and transparency. Other documents may further enhance this set of
capabilities in the future. For instance, signaling for SDH over PDH
ITU-T G.832 or sub-STM-0 ITU-T G.708 interfaces could be defined.

The traffic parameters defined hereafter (see Section 2.1) MUST be
used when the label is encoded as SUKLM as defined in this memo (see
Section 3). They MUST also be used when requesting one of Section/RS
or Line/MS overhead transparent STS-1/STM-0, STS-3*N/STM-N (N=1, 4,
16, 64, 256) signals.

The traffic parameters and label encoding defined in [RFC3471],
Section 3.2, MUST be used for fully transparent STS-1/STM-0,
STS-3*N/STM-N (N=1, 4, 16, 64, 256) signal requests. A fully
transparent signal is one for which all overhead is left unmodified
by intermediate nodes, i.e., when all defined Transparency (T) bits
would be set if the traffic parameters defined in section 2.1 were
used.

2.1. SONET/SDH Traffic Parameters

The traffic parameters for SONET/SDH are organized as follows:

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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Signal Type | RCC | NCC |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NVC | Multiplier (MT) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Transparency (T) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Profile (P) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Annex 1 lists examples of SONET and SDH signal coding.

Signal Type (ST): 8 bits

This field indicates the type of Elementary Signal that comprises the
requested LSP. Several transforms can be applied successively on the
Elementary Signal to build the Final Signal being actually requested
for the LSP.

Each transform application is optional and must be ignored if zero,
except the Multiplier (MT) that cannot be zero and is ignored if
equal to one.

Mannie & Papadimitriou Standards Track [Page 3]

RFC 3946 GMPLS Extensions for SONET/SDH Control October 2004

Transforms must be applied strictly in the following order:

- First, contiguous concatenation (by using the RCC and NCC fields)
can be optionally applied on the Elementary Signal, resulting in a
contiguously concatenated signal.

- Second, virtual concatenation (by using the NVC field) can be
optionally applied on the Elementary Signal resulting in a
virtually concatenated signal.

- Third, some transparency (by using the Transparency field) can be
optionally specified when requesting a frame as signal rather than
an SPE or VC based signal.

- Fourth, a multiplication (by using the Multiplier field) can be
optionally applied either directly on the Elementary Signal, or on
the contiguously concatenated signal obtained from the first
phase, or on the virtually concatenated signal obtained from the
second phase, or on these signals combined with some transparency.

Permitted Signal Type values for SONET/SDH are:

Value Type (Elementary Signal)
----- ------------------------
1 VT1.5 SPE / VC-11
2 VT2 SPE / VC-12
3 VT3 SPE
4 VT6 SPE / VC-2
5 STS-1 SPE / VC-3
6 STS-3c SPE / VC-4
7 STS-1 / STM-0 (only when requesting transparency)
8 STS-3 / STM-1 (only when requesting transparency)
9 STS-12 / STM-4 (only when requesting transparency)
10 STS-48 / STM-16 (only when requesting transparency)
11 STS-192 / STM-64 (only when requesting transparency)
12 STS-768 / STM-256 (only when requesting transparency)

A dedicated signal type is assigned to a SONET STS-3c SPE instead of
coding it as a contiguous concatenation of three STS-1 SPEs. This is
done in order to provide easy interworking between SONET and SDH
signaling.

Appendix 1 adds one signal type (optional) to the above values.

Requested Contiguous Concatenation (RCC): 8 bits

This field is used to request the optional SONET/SDH contiguous
concatenation of the Elementary Signal.

Mannie & Papadimitriou Standards Track [Page 4]

RFC 3946 GMPLS Extensions for SONET/SDH Control October 2004

This field is a vector of flags. Each flag indicates the support of
a particular type of contiguous concatenation. Several flags can be
set at the same time to indicate a choice.

These flags allow an upstream node to indicate to a downstream node
the different types of contiguous concatenation that it supports.
However, the downstream node decides which one to use according to
its own rules.

A downstream node receiving simultaneously more than one flag chooses
a particular type of contiguous concatenation, if any supported, and
based on criteria that are out of this document scope. A downstream
node that doesn't support any of the concatenation types indicated by
the field must refuse the LSP request. In particular, it must refuse
the LSP request if it doesn't support contiguous concatenation at
all.

When several flags have been set, the upstream node retrieves the
(single) type of contiguous concatenation the downstream node has
selected by looking at the position indicated by the first label and
the number of label(s) as returned by the downstream node (see also
Section 3).

The entire field is set to zero to indicate that no contiguous
concatenation is requested at all (default value). A non-zero field
indicates that some contiguous concatenation is requested.

The following flag is defined:

Flag 1 (bit 1): Standard contiguous concatenation.

Flag 1 indicates that the standard SONET/SDH contiguous concatenation
as defined in [T1.105]/[G.707] is supported. Note that bit 1 is the
low order bit. Other flags are reserved for extensions, if not used
they must be set to zero when sent, and should be ignored when
received.

See note 1 hereafter in the section on the NCC about the SONET
contiguous concatenation of STS-1 SPEs when the number of components
is a multiple of three.

Number of Contiguous Components (NCC): 16 bits

This field indicates the number of identical SONET SPEs/SDH VCs
(i.e., Elementary Signal) that are requested to be concatenated, as
specified in the RCC field.

Mannie & Papadimitriou Standards Track [Page 5]

RFC 3946 GMPLS Extensions for SONET/SDH Control October 2004

Note 1: when requesting a SONET STS-Nc SPE with N=3*X, the
Elementary Signal to use must always be an STS-3c_SPE signal type
and the value of NCC must always be equal to X. This allows also
facilitating the interworking between SONET and SDH. In
particular, it means that the contiguous concatenation of three
STS-1 SPEs can not be requested because according to this
specification, this type of signal must be coded using the STS-3c
SPE signal type.

Note 2: when requesting a transparent STS-N/STM-N signal
limited to a single contiguously concatenated STS-Nc_SPE/VC-4-Nc,
the signal type must be STS-N/STM-N, RCC with flag 1 and NCC set
to 1.

The NCC value must be consistent with the type of contiguous
concatenation being requested in the RCC field. In particular, this
field is irrelevant if no contiguous concatenation is requested (RCC
= 0), in that case it must be set to zero when sent, and should be
ignored when received. A RCC value different from 0 must imply a
number of contiguous components greater than 1.

Number of Virtual Components (NVC): 16 bits

This field indicates the number of signals that are requested to be
virtually concatenated. These signals are all of the same type by
definition. They are Elementary Signal SPEs/VCs for which signal
types are defined in this document, i.e., VT1.5_SPE/VC-11,
VT2_SPE/VC-12, VT3_SPE, VT6_SPE/VC-2, STS-1_SPE/VC-3 or
STS-3c_SPE/VC-4.

This field is set to 0 (default value) to indicate that no virtual
concatenation is requested.

Multiplier (MT): 16 bits

This field indicates the number of identical signals that are
requested for the LSP, i.e., that form the Final Signal. These
signals can be either identical Elementary Signals, or identical
contiguously concatenated signals, or identical virtually
concatenated signals. Note that all these signals belong thus to the
same LSP.

The distinction between the components of multiple virtually
concatenated signals is done via the order of the labels that are
specified in the signaling. The first set of labels must describe
the first component (set of individual signals belonging to the first

Mannie & Papadimitriou Standards Track [Page 6]

RFC 3946 GMPLS Extensions for SONET/SDH Control October 2004

virtual concatenated signal), the second set must describe the second
component (set of individual signals belonging to the second virtual
concatenated signal) and so on.

This field is set to one (default value) to indicate that exactly one
instance of a signal is being requested. Intermediate and egress
nodes MUST verify that the node itself and the interfaces on which
the LSP will be established can support the requested multiplier
value. If the requested values can not be supported, the receiver
node MUST generate a PathErr/NOTIFICATION message (see Section
2.2/2.3, respectively).

Zero is an invalid value. If received, the node MUST generate a
PathErr/NOTIFICATION message (see Section 2.2/2.3, respectively).

Note 1: when requesting a transparent STS-N/STM-N signal limited to a
single contiguously concatenated STS-Nc-SPE/VC-4-Nc, the multiplier
field MUST be equal to 1 (only valid value).

Transparency (T): 32 bits

This field is a vector of flags that indicates the type of
transparency being requested. Several flags can be combined to
provide different types of transparency. Not all combinations are
necessarily valid. The default value for this field is zero, i.e.,
no transparency requested.

Transparency, as defined from the point of view of this signaling
specification, is only applicable to the fields in the SONET/SDH
frame overheads. In the SONET case, these are the fields in the
Section Overhead (SOH), and the Line Overhead (LOH). In the SDH
case, these are the fields in the Regenerator Section Overhead
(RSOH), the Multiplex Section overhead (MSOH), and the pointer fields
between the two. With SONET, the pointer fields are part of the LOH.

Note as well that transparency is only applicable when using the
following Signal Types: STS-1/STM-0, STS-3/STM-1, STS-12/STM-4,
STS-48/STM-16, STS-192/STM-64 and STS-768/STM-256. At least one
transparency type must be specified when requesting such a signal
type.

Transparency indicates precisely which fields in these overheads must
be delivered unmodified at the other end of the LSP. An ingress LSR
requesting transparency will pass these overhead fields that must be
delivered to the egress LSR without any change. From the ingress and
egress LSRs point of views, these fields must be seen as unmodified.

Mannie & Papadimitriou Standards Track [Page 7]

RFC 3946 GMPLS Extensions for SONET/SDH Control October 2004

Transparency is not applied at the interfaces with the initiating and
terminating LSRs, but is only applied between intermediate LSRs.

The transparency field is used to request an LSP that supports the
requested transparency type; it may also be used to setup the
transparency process to be applied at each intermediate LSR.

The different transparency flags are the following:

Flag 1 (bit 1): Section/Regenerator Section layer.
Flag 2 (bit 2): Line/Multiplex Section layer.

Where bit 1 is the low order bit. Other flags are reserved, they
should be set to zero when sent, and should be ignored when received.
A flag is set to one to indicate that the corresponding transparency
is requested.

Intermediate and egress nodes MUST verify that the node itself and
the interfaces on which the LSP will be established can support the
requested transparency. If the requested flags can not be supported,
the receiver node MUST generate a PathErr/NOTIFICATION message (see
Section 2.2/2.3, respectively).

Section/Regenerator Section layer transparency means that the entire
frames must be delivered unmodified. This implies that pointers
cannot be adjusted. When using Section/Regenerator Section layer
transparency all other flags MUST be ignored.

Line/Multiplex Section layer transparency means that the LOH/MSOH
must be delivered unmodified. This implies that pointers cannot be
adjusted.

Profile (P): 32 bits

This field is intended to indicate particular capabilities that must
be supported for the LSP, for example monitoring capabilities.

No standard profile is currently defined and this field SHOULD be set
to zero when transmitted and SHOULD be ignored when received.

In the future TLV based extensions may be created.

Mannie & Papadimitriou Standards Track [Page 8]

RFC 3946 GMPLS Extensions for SONET/SDH Control October 2004

2.2. RSVP-TE Details

For RSVP-TE, the SONET/SDH traffic parameters are carried in the
SONET/SDH SENDER_TSPEC and FLOWSPEC objects. The same format is used
both for SENDER_TSPEC object and FLOWSPEC objects. The content of
the objects is defined above in Section 2.1. The objects have the
following class and type:

For SONET ANSI T1.105 and SDH ITU-T G.707:

SONET/SDH SENDER_TSPEC object: Class = 12, C-Type = 4
SONET/SDH FLOWSPEC object: Class = 9, C-Type = 4

There is no Adspec associated with the SONET/SDH SENDER_TSPEC.
Either the Adspec is omitted or an int-serv Adspec with the Default
General Characterization Parameters and Guaranteed Service fragment
is used, see [RFC2210].

For a particular sender in a session the contents of the FLOWSPEC
object received in a Resv message SHOULD be identical to the contents
of the SENDER_TSPEC object received in the corresponding Path
message. If the objects do not match, a ResvErr message with a
"Traffic Control Error/Bad Flowspec value" error SHOULD be generated.

Intermediate and egress nodes MUST verify that the node itself and
the interfaces on which the LSP will be established can support the
requested Signal Type, RCC, NCC, NVC and Multiplier (as defined in
Section 2.1). If the requested value(s) can not be supported, the
receiver node MUST generate a PathErr message with a "Traffic Control
Error/ Service unsupported" indication (see [RFC2205]).

In addition, if the MT field is received with a zero value, the node
MUST generate a PathErr message with a "Traffic Control Error/Bad
Tspec value" indication (see [RFC2205]).

Intermediate nodes MUST also verify that the node itself and the
interfaces on which the LSP will be established can support the
requested Transparency (as defined in Section 2.1). If the requested
value(s) can not be supported, the receiver node MUST generate a
PathErr message with a "Traffic Control Error/Service unsupported"
indication (see [RFC2205]).

2.3. CR-LDP Details

For CR-LDP, the SONET/SDH traffic parameters are carried in the
SONET/SDH Traffic Parameters TLV. The content of the TLV is defined
above in Section 2.1. The header of the TLV has the following
format:

Mannie & Papadimitriou Standards Track [Page 9]

RFC 3946 GMPLS Extensions for SONET/SDH Control October 2004

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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

The type field for the SONET/SDH Traffic Parameters TLV is: 0x0838.

Intermediate and egress nodes MUST verify that the node itself and
the interfaces on which the LSP will be established can support the
requested Signal Type, RCC, NCC, NVC and Multiplier (as defined in
Section 2.1). If the requested value(s) can not be supported, the
receiver node MUST generate a NOTIFICATION message with a "Resource
Unavailable" status code (see [RFC3212]).

In addition, if the MT field is received with a zero value, the node
MUST generate a NOTIFICATION message with a "Resource Unavailable"
status code (see [RFC3212]).

Intermediate nodes MUST also verify that the node itself and the
interfaces on which the LSP will be established can support the
requested Transparency (as defined in Section 2.1). If the requested
value(s) can not be supported, the receiver node MUST generate a
NOTIFICATION message with a "Resource Unavailable" status code (see
[RFC3212]).

3. SONET and SDH Labels

SONET and SDH each define a multiplexing structure. Both structures
are trees whose roots are respectively an STS-N or an STM-N; and
whose leaves are the signals that can be transported via the time-
slots and switched between time-slots within an ingress port and
time-slots within an egress port, i.e., a VTx SPE, an STS-x SPE or a
VC-x. A SONET/SDH label will identify the exact position (i.e.,
first time-slot) of a particular VTx SPE, STS-x SPE or VC-x signal in
a multiplexing structure. SONET and SDH labels are carried in the
Generalized Label per [RFC3473] and [RFC3472].

Note that by time-slots we mean the time-slots as they appear
logically and sequentially in the multiplex, not as they appear after
any possible interleaving.

These multiplexing structures will be used as naming trees to create
unique multiplex entry names or labels. The same format of label is
used for SONET and SDH. As explained in [RFC3471], a label does not
identify the "class" to which the label belongs. This is implicitly
determined by the link on which the label is used.

Mannie & Papadimitriou Standards Track [Page 10]

RFC 3946 GMPLS Extensions for SONET/SDH Control October 2004

In case of signal concatenation or multiplication, a list of labels
can appear in the Label field of a Generalized Label.

In case of contiguous concatenation, only one label appears in the
Label field. This label identifies the lowest time-slot occupied by
the contiguously concatenated signal. By lowest time-slot we mean
the one having the lowest label (value) when compared as integer
values, i.e., the time-slot occupied by the first component signal of
the concatenated signal encountered when descending the tree.

In case of virtual concatenation, the explicit ordered list of all
labels in the concatenation is given. Each label indicates the first
time-slot occupied by a component of the virtually concatenated
signal. The order of the labels must reflect the order of the
payloads to concatenate (not the physical order of time-slots). The
above representation limits virtual concatenation to remain within a
single (component) link; it imposes as such a restriction compared to
the ANSI [T1.105]/ITU-T [G.707] recommendations.

The standard definition for virtual concatenation allows each virtual
concatenation components to travel over diverse paths. Within GMPLS,
virtual concatenation components must travel over the same
(component) link if they are part of the same LSP. This is due to
the way that labels are bound to a (component) link. Note however,
that the routing of components on different paths is indeed
equivalent to establishing different LSPs, each one having its own
route. Several LSPs can be initiated and terminated between the same
nodes and their corresponding components can then be associated
together (i.e., virtually concatenated).

In case of multiplication (i.e., using the multiplier transform), the
explicit ordered list of all labels that take part in the Final
Signal is given. In case of multiplication of virtually concatenated
signals, the first set of labels indicates the time-slots occupied by
the first virtually concatenated signal, the second set of labels
indicates the time-slots occupied by the second virtually
concatenated signal, and so on. The above representation limits
multiplication to remain within a single (component) link.

The format of the label for SONET and/or SDH TDM-LSR link is:

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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| S | U | K | L | M |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Mannie & Papadimitriou Standards Track [Page 11]

RFC 3946 GMPLS Extensions for SONET/SDH Control October 2004

This is an extension of the numbering scheme defined in [G.707]
sections 7.3.7 to 7.3.13, i.e., the (K, L, M) numbering. Note that
the higher order numbering scheme defined in [G.707] sections 7.3.1
to 7.3.6 is not used here.

Each letter indicates a possible branch number starting at the parent
node in the multiplex structure. Branches are considered as numbered
in increasing order, starting from the top of the multiplexing
structure. The numbering starts at 1, zero is used to indicate a
non-significant or ignored field.

When a field is not significant or ignored in a particular context it
MUST be set to zero when transmitted, and MUST be ignored when
received.

When a hierarchy of SONET/SDH LSPs is used, a higher order LSP with a
given bandwidth can be used to carry lower order LSPs. Remember here
that a higher order LSP is established through a SONET/SDH higher
order path layer network and a lower order LSP, through a SONET/SDH
lower order path layer network (see also ITU-T G.803, Section 3 for
the corresponding definitions). In this context, the higher order
SONET/SDH LSP behaves as a "virtual link" with a given bandwidth
(e.g., VC-3), it may also be used as a Forwarding Adjacency. A lower
order SONET/SDH LSP can be established through that higher order LSP.
Since a label is local to a (virtual) link, the highest part of that
label (i.e., the S, U and K fields) is non-significant and is set to
zero, i.e., the label is "0,0,0,L,M". Similarly, if the structure of
the lower order LSP is unknown or not relevant, the lowest part of
that label (i.e., the L and M fields) is non-significant and is set
to zero, i.e., the label is "S,U,K,0,0".

For instance, a VC-3 LSP can be used to carry lower order LSPs. In
that case the labels allocated between the two ends of the VC-3 LSP
for the lower order LSPs will have S, U and K set to zero, i.e.,
non-significant, while L and M will be used to indicate the signal
allocated in that VC-3.

In case of tunneling such as VC-4 containing VC-3 containing
VC-12/VC-11 where the SUKLM structure is not adequate to represent
the full signal structure, a hierarchical approach must be used,
i.e., per layer network signaling.

The possible values of S, U, K, L and M are defined as follows:

1. S=1->N is the index of a particular STS-3/AUG-1 inside an
STS-N/STM-N multiplex. S is only significant for SONET STS-N
(N>1) and SDH STM-N (N>0). S must be 0 and ignored for STS-1 and
STM-0.

Mannie & Papadimitriou Standards Track [Page 12]

RFC 3946 GMPLS Extensions for SONET/SDH Control October 2004

2. U=1->3 is the index of a particular STS-1_SPE/VC-3 within an
STS-3/AUG-1. U is only significant for SONET STS-N (N>1) and SDH
STM-N (N>0). U must be 0 and ignored for STS-1 and STM-0.

3. K=1->3 is the index of a particular TUG-3 within a VC-4. K is
only significant for an SDH VC-4 structured in TUG-3s. K must be
0 and ignored in all other cases.

4. L=1->7 is the index of a particular VT_Group/TUG-2 within an
STS-1_SPE/TUG-3 or VC-3. L must be 0 and ignored in all other
cases.

5. M is the index of a particular VT1.5_SPE/VC-11, VT2_SPE/VC-12 or
VT3_SPE within a VT_Group/TUG-2. M=1->2 indicates a specific VT3
SPE inside the corresponding VT Group, these values MUST NOT be
used for SDH since there is no equivalent of VT3 with SDH. M=3->5
indicates a specific VT2_SPE/VC-12 inside the corresponding
VT_Group/TUG-2. M=6->9 indicates a specific VT1.5_SPE/VC-11
inside the corresponding VT_Group/TUG-2.

Note that a label always has to be interpreted according the
SONET/SDH traffic parameters, i.e., a label by itself does not allow
knowing which signal is being requested (a label is context
sensitive).

The label format defined in this section, referred to as SUKLM, MUST
be used for any SONET/SDH signal requests that are not transparent
i.e., when all Transparency (T) bits defined in section 2.1 are set
to zero. Any transparent STS-1/STM-0/STS-3*N/STM-N (N=1, 4, 16, 64,
256) signal request MUST use a label format as defined in [RFC3471].

The S encoding is summarized in the following table:

S SDH SONET
------------------------------------------------
0 other other
1 1st AUG-1 1st STS-3
2 2nd AUG-1 2nd STS-3
3 3rd AUG-1 3rd STS-3
4 4rd AUG-1 4rd STS-3
: : :
N Nth AUG-1 Nth STS-3

Mannie & Papadimitriou Standards Track [Page 13]

RFC 3946 GMPLS Extensions for SONET/SDH Control October 2004

The U encoding is summarized in the following table:

U SDH AUG-1 SONET STS-3
-------------------------------------------------
0 other other
1 1st VC-3 1st STS-1 SPE
2 2nd VC-3 2nd STS-1 SPE
3 3rd VC-3 3rd STS-1 SPE

The K encoding is summarized in the following table:

K SDH VC-4
---------------
0 other
1 1st TUG-3
2 2nd TUG-3
3 3rd TUG-3

The L encoding is summarized in the following table:

L SDH TUG-3 SDH VC-3 SONET STS-1 SPE
-------------------------------------------------
0 other other other
1 1st TUG-2 1st TUG-2 1st VTG
2 2nd TUG-2 2nd TUG-2 2nd VTG
3 3rd TUG-2 3rd TUG-2 3rd VTG
4 4th TUG-2 4th TUG-2 4th VTG
5 5th TUG-2 5th TUG-2 5th VTG
6 6th TUG-2 6th TUG-2 6th VTG
7 7th TUG-2 7th TUG-2 7th VTG

The M encoding is summarized in the following table:

M SDH TUG-2 SONET VTG
-------------------------------------------------
0 other other
1 - 1st VT3 SPE
2 - 2nd VT3 SPE
3 1st VC-12 1st VT2 SPE
4 2nd VC-12 2nd VT2 SPE
5 3rd VC-12 3rd VT2 SPE
6 1st VC-11 1st VT1.5 SPE
7 2nd VC-11 2nd VT1.5 SPE
8 3rd VC-11 3rd VT1.5 SPE
9 4th VC-11 4th VT1.5 SPE

Mannie & Papadimitriou Standards Track [Page 14]

RFC 3946 GMPLS Extensions for SONET/SDH Control October 2004

Examples of labels:

Example 1: the label for the STS-3c_SPE/VC-4 in the Sth STS-3/AUG-1
is: S>0, U=0, K=0, L=0, M=0.

Example 2: the label for the VC-3 within the Kth-1 TUG-3 within
the VC-4 in the Sth AUG-1 is: S>0, U=0, K>0, L=0, M=0.

Example 3: the label for the Uth-1 STS-1_SPE/VC-3 within the Sth
STS-3/AUG-1 is: S>0, U>0, K=0, L=0, M=0.

Example 4: the label for the VT6/VC-2 in the Lth-1 VT Group/TUG-2
in the Uth-1 STS-1_SPE/VC-3 within the Sth STS-3/AUG-1 is: S>0,
U>0, K=0, L>0, M=0.

Example 5: the label for the 3rd VT1.5_SPE/VC-11 in the Lth-1 VT
Group/TUG-2 within the Uth-1 STS-1_SPE/VC-3 within the Sth STS-
3/AUG-1 is: S>0, U>0, K=0, L>0, M=8.

Example 6: the label for the STS-12c/VC-4-4c which uses the 9th
STS-3/AUG-1 as its first timeslot is: S=9, U=0, K=0, L=0, M=0.

In case of contiguous concatenation, the label that is used is the
lowest label (value) of the contiguously concatenated signal as
explained before. The higher part of the label indicates where the
signal starts and the lowest part is not significant.

In case of STM-0/STS-1, the values of S, U and K must be equal to
zero according to the field coding rules. For instance, when
requesting a VC-3 in an STM-0 the label is S=0, U=0, K=0, L=0, M=0.
When requesting a VC-11 in a VC-3 in an STM-0 the label is S=0, U=0,
K=0, L>0, M=6..9.

Note: when a Section/RS or Line/MS transparent STS-1/STM-0/STS-
3*N/STM-N (N=1, 4, 16, 64, 256) signal is requested, the SUKLM label
format and encoding is not applicable and the label encoding MUST
follow the rules defined in [RFC3471] Section 3.2.

4. Acknowledgments

Valuable comments and input were received from the CCAMP mailing list
where outstanding discussions took place.

Mannie & Papadimitriou Standards Track [Page 15]

RFC 3946 GMPLS Extensions for SONET/SDH Control October 2004

5. Security Considerations

This document introduces no new security considerations to either
[RFC3473] or [RFC3472]. GMPLS security is described in section 11 of
[RFC3471] and refers to [RFC3209] for RSVP-TE and to [RFC3212] for
CR-LDP.

6. IANA Considerations

Three values have been defined by IANA for this document:

Two RSVP C-Types in registry:
http://www.iana.org/assignments/rsvp-parameters

- A SONET/SDH SENDER_TSPEC object: Class = 12, C-Type = 4 (see
section 2.2).

- A SONET/SDH FLOWSPEC object: Class = 9, C-Type = 4 (see section
2.2).

One LDP TLV Type in registry:
http://www.iana.org/assignments/ldp-namespaces

- A type field for the SONET/SDH Traffic Parameters TLV (see section
2.3).

7. References

7.1. Normative References

[G.707] ITU-T Recommendation G.707, "Network Node Interface for
the Synchronous Digital Hierarchy", October 2000.

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.

[RFC2205] Braden, R., Zhang, L., Berson, S., Herzog, S., and S.
Jamin, "Resource ReSerVation Protocol (RSVP) -- Version
1 Functional Specification", RFC 2205, September 1997.

[RFC2210] Wroclawski, J., "The Use of RSVP with IETF Integrated
Services", RFC 2210, September 1997.

[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan,
V., and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, December 2001.

Mannie & Papadimitriou Standards Track [Page 16]

RFC 3946 GMPLS Extensions for SONET/SDH Control October 2004

[RFC3212] Jamoussi, B., Andersson, L., Callon, R., Dantu, R., Wu,
L., Doolan, P., Worster, T., Feldman, N., Fredette, A.,
Girish, M., Gray, E., Heinanen, J., Kilty, T., and A.
Malis, "Constraint-Based LSP Setup using LDP", RFC 3212,
January 2002.

[RFC3471] Berger, L., "Generalized Multi-Protocol Label Switching
(MPLS) Signaling Functional Description", RFC 3471,
January 2003.

[RFC3472] Ashwood-Smith, P. and L. Berger, "Generalized
Multi-Protocol Label Switching (MPLS) Signaling
- Constraint-based Routed Label Distribution Protocol
(CR-LDP) Extensions", RFC 3472, January 2003.

[RFC3473] Berger, L., "Generalized Multi-Protocol Label Switching
(MPLS) Signaling - Resource ReserVation Protocol Traffic
Engineering (RSVP-TE) Extensions", RFC 3473, January
2003.

[RFC3945] Mannie, E., Ed., "Generalized Multiprotocol Label
Switching (GMPLS) Architecture", RFC 3945, October 2004.

[T1.105] "Synchronous Optical Network (SONET): Basic Description
Including Multiplex Structure, Rates, and Formats", ANSI
T1.105, October 2000.

Mannie & Papadimitriou Standards Track [Page 17]

RFC 3946 GMPLS Extensions for SONET/SDH Control October 2004

Appendix 1 - Signal Type Values Extension for VC-3

This appendix defines the following optional additional Signal Type
value for the Signal Type field of section 2.1:

Value Type
----- ---------------------
20 "VC-3 via AU-3 at the end"

According to the ITU-T [G.707] recommendation a VC-3 in the TU-
3/TUG-3/VC-4/AU-4 branch of the SDH multiplex cannot be structured in
TUG-2s, however a VC-3 in the AU-3 branch can be. In addition, a VC-3
could be switched between the two branches if required.

A VC-3 circuit could be terminated on an ingress interface of an LSR
(e.g., forming a VC-3 forwarding adjacency). This LSR could then want
to demultiplex this VC-3 and switch internal low order LSPs. For
implementation reasons, this could be only possible if the LSR
receives the VC-3 in the AU-3 branch. E.g., for an LSR not able to
switch internally from a TU-3 branch to an AU-3 branch on its
incoming interface before demultiplexing and then switching the
content with its switch fabric.

In that case it is useful to indicate that the VC-3 LSP must be
terminated at the end in the AU-3 branch instead of the TU-3 branch.

This is achieved by using the "VC-3 via AU-3 at the end" signal type.
This information can be used, for instance, by the penultimate LSR to
switch an incoming VC-3 received in any branch to the AU-3 branch on
the outgoing interface to the destination LSR.

The "VC-3 via AU-3 at the end" signal type does not imply that the
VC-3 must be switched via the AU-3 branch at some other places in the
network. The VC-3 signal type just indicates that a VC-3 in any
branch is suitable.

Annex 1 - Examples

This annex defines examples of SONET and SDH signal coding. Their
objective is to help the reader to understand how works the traffic
parameter coding and not to give examples of typical SONET or SDH
signals.

As stated above, signal types are Elementary Signals to which
successive concatenation, multiplication and transparency transforms
can be applied to obtain Final Signals.

Mannie & Papadimitriou Standards Track [Page 18]

RFC 3946 GMPLS Extensions for SONET/SDH Control October 2004

1. A VC-4 signal is formed by the application of RCC with value 0,
NCC with value 0, NVC with value 0, MT with value 1 and T with
value 0 to a VC-4 Elementary Signal.

2. A VC-4-7v signal is formed by the application of RCC with value
0, NCC with value 0, NVC with value 7 (virtual concatenation of
7 components), MT with value 1 and T with value 0 to a VC-4
Elementary Signal.

3. A VC-4-16c signal is formed by the application of RCC with flag
1 (standard contiguous concatenation), NCC with value 16, NVC
with value 0, MT with value 1 and T with value 0 to a VC-4
Elementary Signal.

4. An STM-16 signal with Multiplex Section layer transparency is
formed by the application of RCC with value 0, NCC with value 0,
NVC with value 0, MT with value 1 and T with flag 2 to an STM-16
Elementary Signal.

5. An STM-4 signal with Multiplex Section layer transparency is
formed by the application of RCC with flag 0, NCC with value 0,
NVC with value 0, MT with value 1 and T with flag 2 applied to
an STM-4 Elementary Signal.

6. An STM-256 signal with Multiplex Section layer transparency is
formed by the application of RCC with flag 0, NCC with value 0,
NVC with value 0, MT with value 1 and T with flag 2 applied to
an STM-256 Elementary Signal.

7. An STS-1 SPE signal is formed by the application of RCC with
value 0, NCC with value 0, NVC with value 0, MT with value 1 and
T with value 0 to an STS-1 SPE Elementary Signal.

8. An STS-3c SPE signal is formed by the application of RCC with
value 1 (standard contiguous concatenation), NCC with value 1,
NVC with value 0, MT with value 1 and T with value 0 to an STS-
3c SPE Elementary Signal.

9. An STS-48c SPE signal is formed by the application of RCC with
flag 1 (standard contiguous concatenation), NCC with value 16,
NVC with value 0, MT with value 1 and T with value 0 to an STS-
3c SPE Elementary Signal.

10. An STS-1-3v SPE signal is formed by the application of RCC with
value 0, NVC with value 3 (virtual concatenation of 3
components), MT with value 1 and T with value 0 to an STS-1 SPE
Elementary Signal.

Mannie & Papadimitriou Standards Track [Page 19]

RFC 3946 GMPLS Extensions for SONET/SDH Control October 2004

11. An STS-3c-9v SPE signal is formed by the application of RCC with
value 1, NCC with value 1, NVC with value 9 (virtual
concatenation of 9 STS-3c), MT with value 1 and T with value 0
to an STS-3c SPE Elementary Signal.

12. An STS-12 signal with Section layer (full) transparency is
formed by the application of RCC with value 0, NVC with value 0,
MT with value 1 and T with flag 1 to an STS-12 Elementary
Signal.

13. 3 x STS-768c SPE signal is formed by the application of RCC with
flag 1, NCC with value 256, NVC with value 0, MT with value 3,
and T with value 0 to an STS-3c SPE Elementary Signal.

14. 5 x VC-4-13v composed signal is formed by the application of RCC
with value 0, NVC with value 13, MT with value 5 and T with
value 0 to a VC-4 Elementary Signal.

The encoding of these examples is summarized in the following table:

Signal ST RCC NCC NVC MT T
--------------------------------------------------------
VC-4 6 0 0 0 1 0
VC-4-7v 6 0 0 7 1 0
VC-4-16c 6 1 16 0 1 0
STM-16 MS transparent 10 0 0 0 1 2
STM-4 MS transparent 9 0 0 0 1 2
STM-256 MS transparent 12 0 0 0 1 2
STS-1 SPE 5 0 0 0 1 0
STS-3c SPE 6 1 1 0 1 0
STS-48c SPE 6 1 16 0 1 0
STS-1-3v SPE 5 0 0 3 1 0
STS-3c-9v SPE 6 1 1 9 1 0
STS-12 Section transparent 9 0 0 0 1 1
3 x STS-768c SPE 6 1 256 0 3 0
5 x VC-4-13v 6 0 0 13 5 0

Mannie & Papadimitriou Standards Track [Page 20]

RFC 3946 GMPLS Extensions for SONET/SDH Control October 2004

Contributors

Contributors are listed by alphabetical order:

Stefan Ansorge (Alcatel)
Lorenzstrasse 10
70435 Stuttgart, Germany

EMail: [email protected]

Peter Ashwood-Smith (Nortel)
PO. Box 3511 Station C,
Ottawa, ON K1Y 4H7, Canada

EMail:[email protected]

Ayan Banerjee (Calient)
5853 Rue Ferrari
San Jose, CA 95138, USA

EMail: [email protected]

Lou Berger (Movaz)
7926 Jones Branch Drive
McLean, VA 22102, USA

EMail: [email protected]

Greg Bernstein (Ciena)
10480 Ridgeview Court
Cupertino, CA 94014, USA

EMail: [email protected]

Angela Chiu (Celion)
One Sheila Drive, Suite 2
Tinton Falls, NJ 07724-2658

EMail: [email protected]

Mannie & Papadimitriou Standards Track [Page 21]

RFC 3946 GMPLS Extensions for SONET/SDH Control October 2004

John Drake (Calient)
5853 Rue Ferrari
San Jose, CA 95138, USA

EMail: [email protected]

Yanhe Fan (Axiowave)
100 Nickerson Road
Marlborough, MA 01752, USA

EMail: [email protected]

Michele Fontana (Alcatel)
Via Trento 30,
I-20059 Vimercate, Italy

EMail: [email protected]

Gert Grammel (Alcatel)
Lorenzstrasse, 10
70435 Stuttgart, Germany

EMail: [email protected]

Juergen Heiles (Siemens)
Hofmannstr. 51
D-81379 Munich, Germany

EMail: [email protected]

Suresh Katukam (Cisco)
1450 N. McDowell Blvd,
Petaluma, CA 94954-6515, USA

EMail: [email protected]

Kireeti Kompella (Juniper)
1194 N. Mathilda Ave.
Sunnyvale, CA 94089, USA

EMail: [email protected]

Mannie & Papadimitriou Standards Track [Page 22]

RFC 3946 GMPLS Extensions for SONET/SDH Control October 2004

Jonathan P. Lang (Calient)
25 Castilian
Goleta, CA 93117, USA

EMail: [email protected]

Fong Liaw (Solas Research)

EMail: [email protected]

Zhi-Wei Lin (Lucent)
101 Crawfords Corner Rd
Holmdel, NJ 07733-3030, USA

EMail: [email protected]

Ben Mack-Crane (Tellabs)

EMail: [email protected]

Dimitrios Pendarakis (Tellium)
2 Crescent Place, P.O. Box 901
Oceanport, NJ 07757-0901, USA

EMail: [email protected]

Mike Raftelis (White Rock)
18111 Preston Road
Dallas, TX 75252, USA

Bala Rajagopalan (Tellium)
2 Crescent Place, P.O. Box 901
Oceanport, NJ 07757-0901, USA

EMail: [email protected]

Mannie & Papadimitriou Standards Track [Page 23]

RFC 3946 GMPLS Extensions for SONET/SDH Control October 2004

Yakov Rekhter (Juniper)
1194 N. Mathilda Ave.
Sunnyvale, CA 94089, USA

EMail: [email protected]

Debanjan Saha (Tellium)
2 Crescent Place, P.O. Box 901
Oceanport, NJ 07757-0901, USA

EMail: [email protected]

Vishal Sharma (Metanoia)
335 Elan Village Lane
San Jose, CA 95134, USA

EMail: [email protected]

George Swallow (Cisco)
250 Apollo Drive
Chelmsford, MA 01824, USA

EMail: [email protected]

Z. Bo Tang (Tellium)
2 Crescent Place, P.O. Box 901
Oceanport, NJ 07757-0901, USA

EMail: [email protected]

Eve Varma (Lucent)
101 Crawfords Corner Rd
Holmdel, NJ 07733-3030, USA

EMail: [email protected]

Yangguang Xu (Lucent)
21-2A41, 1600 Osgood Street
North Andover, MA 01845, USA

EMail: [email protected]

Mannie & Papadimitriou Standards Track [Page 24]

RFC 3946 GMPLS Extensions for SONET/SDH Control October 2004

Authors' Addresses

Eric Mannie (Consultant)
Avenue de la Folle Chanson, 2
B-1050 Brussels, Belgium
Phone: +32 2 648-5023
Mobile: +32 (0)495-221775

EMail: [email protected]

Dimitri Papadimitriou (Alcatel)
Francis Wellesplein 1,
B-2018 Antwerpen, Belgium
Phone: +32 3 240-8491

EMail: [email protected]

Mannie & Papadimitriou Standards Track [Page 25]

RFC 3946 GMPLS Extensions for SONET/SDH Control October 2004

Full Copyright Statement

Copyright (C) The Internet Society (2004).

This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.

This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Intellectual Property

The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the IETF's procedures with respect to rights in IETF Documents can
be found in BCP 78 and BCP 79.

Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.

The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at ietf-
[email protected].

Acknowledgement

Funding for the RFC Editor function is currently provided by the
Internet Society.

Mannie & Papadimitriou Standards Track [Page 26]