Internet DRAFT - draft-choi-gmpls-label-framework
draft-choi-gmpls-label-framework
Internet Draft Jun Kyun Choi
Document: draft-choi-gmpls-label-framework-01.txt Min Ho Kang
Expiration Date: August 2003 Gyu Myoung Lee
ICU
Joo Uk Um
Yong Jae Lee
KT(Korea Telecom)
Jeong Yun Kim
ETRI
March 2003
Framework for GMPLS Label Encoding
Status of this Memo
This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC-2026.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that other
groups may also distribute working documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsolete 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."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
Abstract
Generalized Multiprotocol Label Switching (GMPLS) extends the MPLS
control plane to encompass packet switching, time-division, lambda
and fiber switching. The new forms of label which used in GMPLS to
deal with the widening scope of MPLS into the optical and time domain
are collectively referred to as a "Generalized Label". In this draft
for extending MPLS label specification [5], we describe the concept
and characteristics of Generalized Label for GMPLS. We also discuss
the format and considerations for label encoding. Particularly we
present the necessity of mapping rule at ingress and egress switching
interface where data flows with label of a different granularity are
merged into the aggregated data flow of large bandwidth.
Choi et al Expires - August 2003 [Page 1]
Framework for GMPLS Label Encoding March 2003
Conventions
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.
Table of Contents
1. Introduction.....................................................3
2. Generalized Label................................................4
2.1. The definition of Generalized Label.........................4
2.2. The Classification of Generalized Label.....................4
2.2.1. label for packet switch capable (PSC)...................4
2.2.2. label for Time Division Multiplex Capable (TDM).........5
2.2.3. label for Lambda Switch Capable(LSC) and Fiber Switch
Capable(FSC)...................................................5
2.3. The relationship of label and switching interfaces..........6
2.4. Generalized Label Hierarchy.................................6
3. GMPLS label encoding.............................................8
3.1. Generalized Label Format....................................8
3.2. Label Encoding for Packet Switching Capable (PSC)...........8
3.3. Label Encoding for TDM time slot............................8
3.4. Label Encoding for Lambda Switch Capable (LSC) and Fiber
Switch Capable (FSC).............................................8
3.4.1. lambda and port label format............................8
3.4.2. lambda label encoding...................................9
3.4.3. waveband label encoding.................................9
3.4.4. port label encoding....................................10
4. Considerations for implementation...............................10
5. Security Considerations.........................................11
Appendix. Summary of GMPLS label encoding specifications...........12
References.........................................................14
Acknowledgments....................................................15
Author's Addresses.................................................15
Choi et al Expires - August 2003 [Page 2]
Framework for GMPLS Label Encoding March 2003
1. Introduction
Generalized Multiprotocol Label Switching (GMPLS) extends MPLS from
supporting 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 Capable (TDM),
Lambda Switch Capable (LSC) and Fiber Switch Capable (FSC) [1]. GMPLS
signaling specification [1] presents a functional description of the
extensions to MPLS signaling needed to support these new classes of
interfaces and switching. GMPLS Signaling such as RSVP-TE extensions
[2] and CR-LDP extensions [3] includes the specific formats and
mechanisms to support four classes of interfaces.
In MPLS, a label is a short, fixed length, locally significant
identifier which is used to identify a FEC. The label which is put on
a particular packet represents the Forwarding Equivalence Class (FEC)
to which that packet is assigned [4]. This label value does not
necessarily imply a relationship to bandwidth or characteristics
(e.g., frequency band, time slot information, etc) data flows. On the
other hand, in GMPLS, to deal with the widening scope of MPLS into
the optical and time domain, several new forms of "label" are
required. These new forms of label are collectively referred to as a
"Generalized Label".
In GMPLS, the meanings of label are different from each other and
MUST be identify data flows with several switching type. Therefore,
the specific label encoding rule for each interface MUST be specified.
At present, the encoding rules for MPLS label and TDM label are
defined in related specifications [5],[6],[7]. In GMPLS-based optical
network, we SHOULD consider the multiple granularities that label
represents. So in GMPLS label hierarchy, data flows with small
bandwidth need to be merged and aggregated in fiber and/or wavelength
with large bandwidth. In this case, a Label Switched Path (LSP) such
as lambda LSP and fiber LSP includes several kinds of labels. However,
label format for optical interface such as wavelength and fiber is
defined but the specific encoding and mapping rule doesn't be defined.
Therefore, it is very important to specify the label allocation rule
that is taken optical characteristic into consideration and manage
the label with a different granularity.
To support GMPLS, we SHOULD extend label encoding rule defined the
existing MPLS label specification [5]. Therefore, in this draft, we
describe the concept and characteristics of Generalized Label for
GMPLS. We also discuss the format and considerations for label
encoding. Particularly we present the necessity of mapping rule at
ingress and egress switching interface where data flows with label of
a different granularity are merged into the aggregated data flow of
large bandwidth. Using this rule, we can control and manage data
flows with several labels inside GMPLS control domain.
Choi et al Expires - August 2003 [Page 3]
Framework for GMPLS Label Encoding March 2003
2. Generalized Label
2.1. The definition of Generalized Label
The Generalized Label extends the traditional label by allowing the
representation of not only labels which travel in-band with
associated data packets, but also labels which identify time-slots,
wavelengths, or space division multiplexed positions [1]. Therefore,
the Generalized Label includes the various meanings according to
different switching interfaces and implies the available bandwidth
for the corresponding data flow. In the followings, we summarize the
characteristics of Generalized Label in GMPLS signaling specification
[1].
- Values used in Generalized Label field only have significance
between two neighbors, and the receiver may need to convert the
received value into a value that has local significance.
- A Generalized Label does not identify the "class" to which the
label belongs. This is implicit in the multiplexing
capabilities of the link on which the label is used.
- A Generalized Label only carries a single level of label, i.e.,
it is non-hierarchical. When multiple levels of label (LSPs
within LSPs) are required, each LSP MUST be established
separately.
- Each Generalized Label object carries a variable length label
parameter.
In the following section, we describe various kinds of label.
2.2. The Classification of Generalized Label
2.2.1. label for packet switch capable (PSC)
Packet Switch Capable (PSC) interface can switch the received data on
a packet-by-packet basis. This interface recognizes packet/cell
boundaries and can forward data based on the content of the
packet/cell header. The label carried in the "shim" header [5] is
used in this interface. We define all kinds of label used in PSC
interface as "MPLS label".
- MPLS label
This label represents a generic MPLS label, a Frame Relay label,
or an ATM label. Generic MPLS labels and Frame Relay labels are
encoded right justified aligned in 32 bits (4 octets). ATM labels
are encoded with the VPI right justified in bits 0-15 and the VCI
right justified in bits 16-31 [1].
Choi et al Expires - August 2003 [Page 4]
Framework for GMPLS Label Encoding March 2003
2.2.2. label for Time Division Multiplex Capable (TDM)
Time Division Multiplex Capable (TDM) interface forwards data based
on the data's time slot in a repeating cycle. TDM interface can
multiplex or demultiplex channels within a frame such as SDH payload.
The followings are the descriptions of label for TDM.
- SONET/SDH label
This label identifies the exact position (i.e. first time-slot) of
a particular VTx SPE, STS-x SPE or VC-x signal in a multiplexing
structure [6]. Multiplexing structure for SONET/SDH is based on
ANSI [8]/ITU-T G.707 [9] recommendations.
- G.709 label
In G.709 optical transport network, this label identifies the
exact position of a particular ODUj signal in an ODUk multiplexing
structure. To the support of ODUk mapping into OTUk, this label
supports the sub-levels of ODUk multiplexing. ODUk multiplexing
refers to multiplexing of ODUj (j = 1, 2) into an ODUk (k > j).
These multiplexing structures are based on ITU-T G.709 [10]
recommendation [7].
2.2.3. label for Lambda Switch Capable(LSC) and Fiber Switch
Capable(FSC)
Lambda Switch Capable (LSC) interface forwards data based on the
wavelength on which the data is received. Therefore, this interface
can recognize and switch individual lambdas within the interface. An
example of such an interface is an Optical Cross-Connect (OXC) switch
that can operate at the level of an individual wavelength. The
followings are the descriptions of label for Lambda Switch Capable
(LSC).
- lambda label
This label represents a single wavelength within a waveband (or
fiber).
- waveband label
Waveband represents a set of contiguous wavelengths which can be
switched together to a new waveband. So, this label represents a
single wavelength within a waveband (or fiber).
Note: in waveband switching, the switching interface can recognize
and switch individual waveband within the link (without
distinguishing lambda, channels or packets).
Fiber Switch Capable (FSC) interface forward data based on a position
of the data in the real world physical spaces. Therefore, this
interface can switch the entire contents to another interface
(without distinguishing lambdas, channels or packets). Fiber
Choi et al Expires - August 2003 [Page 5]
Framework for GMPLS Label Encoding March 2003
switching system switches at the granularity of an entire interface,
and can not exact individual lambdas within the interface. This
interface uses port label.
- port label
This label represents a single fiber in a bundle
2.3. The relationship of label and switching interfaces
Carrying label information on a given link depends on the switching
capability of interface between the ends of the link [11]. The
relationship of labels and switching interfaces is shown in Figure 1.
+-----+ "Shim" header +-----+ +-----+ Lambda +-----+
| PSC |----------------| PSC | | PSC |----------------| LSC |
+-----+ +-----+ +-----+ (waveband) +-----+
+-----+ TDM time slot +-----+ +-----+ port +-----+
| TDM |----------------| TDM | | PSC |----------------| FSC |
+-----+ +-----+ +-----+ +-----+
+-----+ Lambda +-----+ +-----+ Lambda +-----+
| LSC |----------------| LSC | | TDM |----------------| LSC |
+-----+ (waveband) +-----+ +-----+ (waveband) +-----+
+-----+ Port +-----+ +-----+ Port +-----+
| FSC |----------------| FSC | | TDM |----------------| FSC |
+-----+ +-----+ +-----+ +-----+
+-----+ TDM time slot +-----+ +-----+ Port +-----+
| PSC |----------------| TDM | | LSC |----------------| FSC |
+-----+ +-----+ +-----+ +-----+
Figure 1. The relationship of labels and switching interfaces
2.4. Generalized Label Hierarchy
In GMPLS-based optical network, the functionality to simultaneously
switch different levels of granularity inside a given network can be
supported. Therefore, GMPLS label makes a hierarchical architecture.
The label hierarchy of GMPLS is shown in Figure 2. At the top of the
hierarchy are nodes that do fiber switching using port label of Fiber
Switch Capable (FSC) interfaces. Underneath are nodes that do OXC
switching using lambda (waveband) label of Lambda Switch Capable
(LSC) interfaces, followed by TDM time slot switching such as SONET,
SDH and ADM using SONET/SDH label of Time Division Multiplex Capable
(TDM) interfaces, and finally, nodes that do packet switching using
Choi et al Expires - August 2003 [Page 6]
Framework for GMPLS Label Encoding March 2003
MPLS label of Packet Switch Capable (PSC) interfaces. See [12] for
more information on the concept of GMPLS hierarchies.
"shim" header
+-----++ +------+
+-----++ ----->|SONET | +-----++-----++
| SDH |\ +-----++-----++
+-----++ ----->| ADM | \ TDM Multiplexing
+-----++ +------+ \
| SONET/SDH \
MPLS Label | Label \ +---------+
| \ | OXC | LSC
| -->|Switching|\
| +---------+ \
| | Lambda \
| | (waveband) \ +---------+
| | Label \ | Fiber |
| | ---->|Switching|
| | +---------+
| | | |FSC
| | | +-------->
| | | Port Label
---------------------------------------------------------------------
MPLS Label | MPLS Label | MPLS Label | MPLS Label
| SONET/SDH Label | SONET/SDH Label | SONET/SDH Label
| | Lambda Label | Lambda Label
| | | Port Label
---------------------------------------------------------------------
| | | Fiber LSP
| | |<------------------
| | Lambda LSP
| |<-------------------------------------
| TDM time slot (TDM) LSP
|<--------------------------------------------------------
Packet LSP
<--------------------------------------------------------------------
Figure 2. GMPLS label hierarchy
The data flows that have MPLS shim header are transferred through a
packet LSP that originates between two packet switches. The data
flows are aggregated in TDM switch such as SONET and SDH. The
aggregated data flows with new SONET/SDH label are multiplexed inside
a TDM time slot LSP between two TDM switches. Similarly, the
multiplexed data flows with new lambda (waveband) label can be
transferred inside a lambda LSP that originates between two lambda
switches. Finally the data flows with new port label can be
transferred inside a fiber LSP that originates between two fiber
switches. Reversely, these data flows MUST be recovered in lower
switching interface using label information. Therefore, using GMPLS
signaling each switching interface determines the label value to use
Choi et al Expires - August 2003 [Page 7]
Framework for GMPLS Label Encoding March 2003
and keeps the mapping information between label and data flow. In
particular, when each data flow with small bandwidth is merged into a
data flow with large bandwidth, ingress and egress switching
interface SHOULD know the information that data flows are multiplexed
and demultiplexed in a synchronous and/or asynchronous manner for
sharing resource (i.e., wavelength etc), see Section 4.
3. GMPLS label encoding
3.1. Generalized Label Format
As currently proposed in GMPLS signaling specification [1], the
Generalized Label has the following format.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label |
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Label: Variable
Generalized Label carries label information of variable length. The
interpretation of this field depends on the type of the link over
which the label is used. Therefore, according to classes of interface
and switching, the rule for label encoding MUST be specified. In the
following section, we discuss the details of label encoding for each
switching capable interface.
3.2. Label Encoding for Packet Switching Capable (PSC)
See Appendix.1 for information on MPLS label encoding
3.3. Label Encoding for TDM time slot
See Appendix.2 for information on TDM time slot label encoding
3.4. Label Encoding for Lambda Switch Capable (LSC) and Fiber Switch
Capable (FSC)
3.4.1. lambda and port label format
As currently proposed in GMPLS signaling specification [1], lambda
label and port label has the 32bit label space as shown the following
format.
Choi et al Expires - August 2003 [Page 8]
Framework for GMPLS Label Encoding March 2003
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Label: 32 bits
This label information indicates port/fiber or lambda to be used,
from the perspective of the sender of the object/TLV in GMPLS
signaling [2], [3].
3.4.2. lambda label encoding
Lambda label encoding SHOULD consider the following attributes that
represent lambda characteristics.
- The wavelength of the selected lambda (Frequency band): This value
can imply bandwidth for the corresponding data flow.
- Modulation (WDM, SCM)
- Additional information
We will define the concrete flag and field for lambda label encoding
in the next time.
3.4.3. waveband label encoding
As currently defined in [1], the waveband label space definition is
suitable and does not require any modification or extension. In the
context of waveband switching, the generalized label has the
following format:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Waveband Id |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Start Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| End Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Waveband Id: 32 bits
A waveband identifier. The value is selected by the sender
and reused in all subsequent related messages.
Start Label: 32 bits
Indicates the channel identifier of the lowest value
wavelength making up the waveband, from the object/TLV
sender's perspective.
Choi et al Expires - August 2003 [Page 9]
Framework for GMPLS Label Encoding March 2003
End Label: 32 bits
Indicates the channel identifier of the highest value
wavelength making up the waveband, from the object/TLV
sender's perspective.
Channel identifiers of start label and end label use the same label
parameter that will be defined in lambda label encoding (section
3.4.2).
3.4.4. port label encoding
Similar to lambda label encoding, port label encoding SHOULD consider
attributes that represent fiber characteristics.
We will define the concrete flag and field for lambda label encoding
in the next time.
4. Considerations for implementation
- Multiplexing in optical switching interface
Let consider the case that data flows with label of a different
granularity are merged into the aggregated data flow of large
bandwidth in optical switching interface such as LSC and FSC. Figure
3 represents a simple example of multiplexing in OXC with LSC. Each
switch performs multiplexing and demultiplexing for the purpose of
sharing optical resource. These flows may be merged in a synchronous
or/and synchronous manner of time domain according to switching
schemes. Similar to label stacking, several flows with label are
stacked. For TDM, label can represent the allocated time slot of the
TDM hierarchy in use. Otherwise, each switching interface SHOULD have
mapping information that each flow is located at a certain point of
optical resource (e.g., wavelength etc). Therefore, mapping rule for
implementation SHOULD be defined.
+-----+--+ +-----+--+-----+--+--+ +-----+--+
|flow1|M1|\ +-----+ |flow2|M2|flow1|M1|L1| +-----+ /|flow1|M1|
+-----+--+ \| OXC | +-----+--+-----+--+--+ | OXC |/ +-----+--+
+-----+--+ /|(LSC)|--------------------------|(LSC)|\ +-----+--+
|flow2|M2|/ +-----+ +-----+ \|flow2|M2|
+-----+--+ Multiplexing Demultiplexing +-----+--+
M1,M2: MPLS label L1: lambda label
Figure 3. Example of multiplexing in optical switching interface
- Unnumbered link and link bundling
Choi et al Expires - August 2003 [Page 10]
Framework for GMPLS Label Encoding March 2003
Support of unnumbered link [13] has been introduced to address the
scalability issues of assigning IP address to earn link of an optical
switch. This is because the link of an optical switch may correspond
to a fiber, lambda, or even TDM channel, depending on the switching
granularity of the link. This reduces the management effort in
configuring IP addresses and tracking allocated IP addresses,
especially with optical network having large numbers of links.
Link bundling [14] can be used to aggregate multiple parallel links
into a single "bundled link" for IGP scaling purposes. This is
important for optical networks, as hundreds of parallel fibers will
be developed between switches and each fiber may obtain hundreds of
wavelengths.
In GMPLS label encoding, we MAY consider to represent unnumbered link
and link bundling as "label".
- Label stacking
The traditional MPLS supports label stacking that is a more general
model in which a labeled packet carries a number of labels, organized
as a last-in, first-out stack [4]. This concept can be applied to the
GMPLS LSP hierarchy.
5. Security Considerations
This document does not have any security concerns. The security
requirements using this document are described in the referenced
documents.
Choi et al Expires - August 2003 [Page 11]
Framework for GMPLS Label Encoding March 2003
Appendix. Summary of GMPLS label encoding specifications
1. label encoding for packet switching capable (PSC) link [5]
The label stack is represented as a sequence of "label stack
entries". Each label stack entry is represented by 4 octets. The
format of the label for packet switching capable (PSC) 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Label
| Label | Exp |S| TTL | Stack
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Entry
Label: Label Value, 20 bits
Exp: Experimental Use, 3 bits
S: Bottom of Stack, 1 bit
TTL: Time to Live, 8 bits
The label stack entries appear AFTER the data link layer headers, but
BEFORE any network layer headers. The top of the label stack appears
earliest in the packet, and the bottom appears latest. The network
layer packet immediately follows the label stack entry which has the
S bit set.
The details of each label entry are shown in [5].
2. label encoding for TDM time slot
2.1 label encoding for SONET/SDH [6]
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This is an extension of the (K, L, M) numbering scheme defined in
[15]. The higher order numbering scheme defined in [15] is not used.
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.
Choi et al Expires - August 2003 [Page 12]
Framework for GMPLS Label Encoding March 2003
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".
2.2 label encoding for G.709 optical transport network [7]
The format of the label for the G.709 Digital Path Layer label or
ODUk label 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+
| Reserved | t3 | t2 |t1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+
The specification of the three fields t1, t2 and t3 self-consistently
characterizes the ODUk label space. The value space of the t1, t2 and
t3 fields is defined as follows:
1. t1 (1-bit):
- t1=1 indicates an ODU1 signal.
- t1 is not significant for the other ODUk signal types(t1=0).
2. t2 (3-bit):
- t2=1 indicates a not further sub-divided ODU2 signal.
- t2=2->5 indicates the tributary slot (t2th-2) used by the
ODU1 in an ODTUG2 mapped into an ODU2 (via OPU2).
- t2 is not significant for an ODU3 (t2=0).
3. t3 (6-bit):
- t3=1 indicates a not further sub-divided ODU3 signal.
- t3=2->17 indicates the tributary slot (t3th-1) used by the
ODU1 in an ODTUG3 mapped into an ODU3 (via OPU3).
- t3=18->33 indicates the tributary slot (t3th-17) used by
the ODU2 in an ODTUG3 mapped into an ODU3 (via OPU3).
Note: in case of ODU2 into ODU3 multiplexing, 4 labels are
required to identify the 4 tributary slots used by the ODU2; these
tributary time slots have to be allocated in ascending order.
Choi et al Expires - August 2003 [Page 13]
Framework for GMPLS Label Encoding March 2003
References
[1] Lou Berger, et al. "Generalized MPLS - Signaling Functional
Description", RFC3471, January 2003.
[2] Lou Berger, et al. "Generalized MPLS Signaling - RSVP-TE
Extensions", RFC3473, January 2003.
[3] Peter Ashwood-Smith, et al. "Generalized MPLS Signaling - CR-LDP
Extensions", RFC3472, January 2003.
[4] E. Rosen, "Multiprotocol Label Switching Architecture", RFC3031,
January 2001.
[5] E. Rosen., et al. "MPLS Label Stack Encoding", RFC3032, January
2001.
[6] Eric Mannie., et al. "Generalized Multiprotocol Label Switching
Extensions for SONET and SDH Control", Internet-Draft draft-
ietf-ccamp-gmpls-sonet-sdh-07.txt, work in progress, October
2002.
[7] D. Papadimitriou., et al. "Generalized MPLS Signalling
Extensions for G.709 Optical Transport Networks Control",
Internet-Draft draft-ietf-ccamp-gmpls-g709-03.txt, work in
progress, November 2002.
[8] ANSI T1.105, "Synchronous Optical Network (SONET): Basic
Description Including Multiplex Structure, Rates, and Formats",
October 2000.
[9] ITU-T Recommendation G.707, "Network Node Interface for the
Synchronous Digital Hierarchy", October 2000.
[10] ITU-T Recommendation G.709, version 1.0 (and Amendment 1),
"Interface for the Optical Transport Network(OTN)", February
2001 (and October 2001).
[11] K. Kompella, et al. "Routing Extensions in Support of
Generalized MPLS", Internet-Draft draft-ietf-ccamp-gmpls-
routing-05.txt, work in progress, August 2002.
[12] Kireeti Kompella, et al. "LSP Hierarchy with Generalized MPLS
TE", Internet-Draft draft-ietf-mpls-lsp-hierarchy-08.txt, work
in progress, September 2002.
[13] Eric Mannie, et al. "Generalized Multi-Protocol Label Switching
(GMPLS) Architecture", Internet-Draft draft-ietf-ccamp-gmpls-
architecture-03.txt, work in progress, August 2002.
Choi et al Expires - August 2003 [Page 14]
Framework for GMPLS Label Encoding March 2003
[14] Kireeti Kompella, et al. "Link Bundling in MPLS Traffic
Engineering", Internet-Draft draft-ietf-mpls-bundle-04.txt, work
in progress, July 2002.
[15] ITU-T Recommendation G.707, "Network Node Interface for the
Synchronous Digital Hierarchy", October 2000.
Acknowledgments
This work was supported in part by the Korean Science and Engineering
Foundation (KOSEF) through OIRC project.
Author's Addresses
Jun Kyun Choi
Information and Communications University (ICU)
58-4 Hwa Ahm Dong, Yuseong, Daejeon
Korea 305-732
Phone: +82-42-866-6122
Email: jkchoi@icu.ac.kr
Min Ho Kang
Information and Communications University (ICU)
58-4 Hwa Ahm Dong, Yuseong, Daejeon
Korea 305-732
Phone: +82-42-866-6136
Email: mhkang@icu.ac.kr
Gyu Myoung Lee
Information and Communications University (ICU)
58-4 Hwa Ahm Dong, Yuseong, Daejeon
Korea 305-732
Phone: +82-42-866-6231
Email: gmlee@icu.ac.kr
Joo Uk Um
KT(Korea Telecom)
206 Jungja-dong, Bungdang-gu, Sungnam-City
Kyunggi Province, 463-711, Korea
Phone:+82-31-727-6610
Email: Jooukum@kt.co.kr
Yong Jae Lee
KT(Korea Telecom)
206 Jungja-dong, Bungdang-gu, Sungnam-City
Kyunggi Province, 463-711, Korea
Choi et al Expires - August 2003 [Page 15]
Framework for GMPLS Label Encoding March 2003
Phone:+82-31-727-6610
Email: cruiser@kt.co.kr
Jeong Yun Kim
ETRI (Electronics and Telecommunications Research Institute)
161 KaJong-Dong, Yusong-Gu, Daejeon
Korea 305-309
Phone: +82-42-866-5311
Email: jykim@etri.re.kr
Full Copyright Statement
"Copyright (C) The Internet Society (date). All Rights Reserved.
This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph
are included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than
English.
The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assigns.
This document and the information contained herein is provided on an
"AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
TASK FORCE DISCLAIMS 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."
Document: draft-choi-gmpls-label-framework-01.txt
Expiration Date: August 2003
Choi et al Expires - August 2003 [Page 16]
