CCAMP Working Group Ashok Kunjidhapatham
Internet-Draft Rajan Rao
Intended status: Proposed Standard Biao Lu
Expires: September 15, 2011 Snigdho Bardalai
Khuzema Pithewan
Infinera Corp
John E Drake
Juniper Networks
Steve Balls
Metswitch Networks
March 14, 2011
OSPF TE Extensions for Generalized MPLS (GMPLS) Control of
G.709 Optical Transport Networks
draft-ashok-ccamp-gmpls-ospf-g709-03.txt
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Abstract
As OTN network capabilities continue to evolve, there is an increased
need to support GMPLS control for the same. [RFC4328] introduced
GMPLS signaling extensions for supporting the early version of G.709
[G.709-v1]. The basic routing considerations from signaling
perspective is also specified in [RFC4328].
The recent revision of ITU-T Recommendation G.709 [G.709-v3] and
[GSUP.43] have introduced new ODU containers (both fixed and
flexible) and additional ODU multiplexing capabilities, enabling
support for optimal service aggregation.
This document describes OSPF protocol extensions to support
Generalized MPLS (GMPLS) control for routing services over the
standardized OTU/ODU containers in support of ODU based TDM
switching. Routing support for Optical Channel Layer switching
(Lambda switching) is not covered in this document.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Conventions used in this document . . . . . . . . . . . . . . . 5
3. OTU/ODU Link Representation . . . . . . . . . . . . . . . . . . 5
3.1. OTUk TE-Link . . . . . . . . . . . . . . . . . . . . . . . 5
3.2. ODUk TE-Link . . . . . . . . . . . . . . . . . . . . . . . 6
3.3. ODUj TE-Link . . . . . . . . . . . . . . . . . . . . . . . 6
3.4. Bundled TE-Link . . . . . . . . . . . . . . . . . . . . . . 7
3.5. OTU/ODU Link Property Agreement . . . . . . . . . . . . . . 7
4. OTU/ODU Link Bandwidth Model . . . . . . . . . . . . . . . . . . 8
5. OSPF TE-LSA Extension . . . . . . . . . . . . . . . . . . . . . 9
5.1. Maximum Bandwidth . . . . . . . . . . . . . . . . . . . . . 9
5.2. Maximum Reservable Bandwidth . . . . . . . . . . . . . . . 9
5.3. Unreserved Bandwidth . . . . . . . . . . . . . . . . . . . 9
5.4. Interface Switch Capability Descriptor . . . . . . . . . . 9
5.4.1 ODU Switching . . . . . . . . . . . . . . . . . . . . 11
5.4.2. ODUk Switch Capability Specific Information . . . . 11
5.4.2.1 Bandwidth sub TLV for fixed ODUj . . . . . . . . 12
5.4.2.2 Bandwidth sub-TLV for ODUflex . . . . . . . . . 13
5.5. Interface Multiplexing Capability Descriptor . . . . . . 13
5.5.1 Multiplex Layers and Hierarchical LSP . . . . . . . . 14
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5.5.2 IMCD format . . . . . . . . . . . . . . . . . . . . . 15
5.5.2.1 G-PID . . . . . . . . . . . . . . . . . . . . . 16
5.5.2.2 Available Bandwidth . . . . . . . . . . . . . . 17
5.5.3 Controlling IMCD advertisement . . . . . . . . . . . 17
5.5.4 How to use IMCDs for FA creation . . . . . . . . . . 18
5.5.5 IMCD and non OTN services . . . . . . . . . . . . . . 18
6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
6.1. Network with no IMCD advertisement (no FA support) . . . 19
6.2. Network with IMCD advertisement for FA support . . . . . 20
6.3. Link bundle with similar muxing capabilities . . . . . . 22
6.4. Link bundle with dissimilar muxing capabilities: Layer
relation . . . . . . . . . . . . . . . . . . . . . . . . 23
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 25
10.1. Normative References . . . . . . . . . . . . . . . . . 25
10.2. Informative References . . . . . . . . . . . . . . . . 25
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 26
Author's Addresses . . . . . . . . . . . . . . . . . . . . . . . 26
Appendix A: Abbreviations & Terminology . . . . . . . . . . . . 28
A.1 Abbreviations: . . . . . . . . . . . . . . . . . . . . . . 28
A.2 Terminology . . . . . . . . . . . . . . . . . . . . . . . 28
Appendix B : Optimization Techniques . . . . . . . . . . . . . . 30
B.1 Multiple ISCDs Vs. Single ISCD . . . . . . . . . . . . . . 30
B.1 Multiple IMCDs Vs. Single IMCD . . . . . . . . . . . . . . 30
B.1 Eight priorities Vs. restricted number of priorities . . . 30
Appendix C: Relation with MLN & MRN . . . . . . . . . . . . . . . 30
Appendix D : AMP, BMP & GMP Mapping . . . . . . . . . . . . . . . 30
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1. Introduction
Generalized Multi-Protocol Label Switching (GMPLS) [RFC3945] extends
MPLS from supporting Packet Switching Capable (PSC) interfaces and
switching to include support of four new classes of interfaces and
switching: Layer-2 Switching (L2SC), Time-Division Multiplex (TDM),
Lambda Switch (LSC), and Fiber-Switch (FSC) Capable. A functional
description of the extensions to MPLS signaling that are needed to
support these new classes of interfaces and switching is provided in
[RFC3471]. OSPF extensions for supporting GMPLS are defined in
[RFC4203].
ITU-T Recommendations G.709 and G.872 provide specifications for OTN
interface and network architecture respectively. As OTN network
capabilities continue to evolve; there is an increased need to
support GMPLS control for the same.
GMPLS signaling extensions to support G.709 OTN interfaces are
specified in [RFC4328]. The basic routing considerations from
signaling perspective is specified. G.709 specifications evolved
rapidly over the last few years. Following are the features added
in OTN since the first version [G.709-v1].
(a) OTU Containers:
Pre-existing Containers: OTU1, OTU2 and OTU3
New Containers introduced in [G.709-v3]: OTU2e and OTU4
New Containers introduced in [GSUP.43]: OTU1e, OTU3e1 and OTU3e2
(b) Fixed ODU Containers:
Pre-existing Containers: ODU1, ODU2 and ODU3
New Containers introduced in [G.709-v3]: ODU0, ODU2e and ODU4
New Containers introduced in [GSUP.43]: ODU1e, ODU3e1 and ODU3e2
(c) Flexible ODU Containers:
ODUflex for CBR and GFP-F mapped services. ODUflex uses 'n'
number of OPU Tributary Slots where 'n' is different from the
number of OPU Tributary Slots used by the Fixed ODU Containers.
(d) Tributary Slot Granularity:
OPU2 and OPU3 support two Tributary Slot Granularities:
(i) 1.25Gbps and (ii) 2.5Gbps.
(e) Multi-stage ODU Multiplexing:
Multi-stage multiplexing of LO-ODUs into HO-ODU is supported.
Also, multiplexing could be heterogeneous (meaning LO-ODUs of
different rates can be multiplexed into a HO-ODU).
OTN networks support switching at two layers: (i) ODU Layer - TDM
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Switching and (ii) OCH Layer - Lambda (LSC) Switching. The nodes on
the network may support one or both the switching types. When
multiple switching types are supported MRN/MLN based routing
[RFC5212] and [RFC6001] is assumed.
This document covers OSPF extensions to support routing over the
standardized OTU/ODU containers in support of ODU Layer based TDM
switching as outlined in the framework document [G.709-FRAME].
The Interface Switch Capability Descriptor extensions for ODU Layer
switching and bandwidth representation for ODU containers are
defined in this document.
Routing support for Optical Channel Layer switching (LSC) is beyond
the scope of this document. Refer to [WSON-FRAME] for further
details.
2. Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document is to be interpreted as described in RFC-2119 [RFC2119].
In addition, the reader is assumed to be familiar with the
terminology used in ITU-T [G.709-v3], [G.872] and [GSUP.43], as
well as [RFC4201] and [RFC4203]. Abbreviations used in this
document is detailed in Appendix A.
3. OTU/ODU Link Representation
G.709 OTU/ODU Links are represented as TE-Links in GMPLS Traffic
Engineering Topology for supporting ODU layer switching. These
TE-Links can be modeled in multiple ways. Some of the prominent
representations are captured below.
3.1. OTUk TE-Link
OTUk Link can be modeled as a TE-Link. Switching at ODUk layer
and ODUj layer (including multi-stage multiplexing) can be managed on
OTUk TE-Link. Figure-1 below provides an illustration of this link
type.
When a LO-ODU layer being switched on an OTUk interface involves
multi-stage multiplexing, all the HO-ODU layer(s) should
necessarily terminate between the same pair of nodes as the OTUk
layer in this case. For example, if ODU1 layer switching is
configured on a OTU3 link via multiplexing hierarchy
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ODU3<-ODU2<-ODU1, HO-ODUs (namely ODU3 & ODU2) should terminate
between the same pair of nodes as OTU3 layer.
+-------+ +-------+ +-------+
| OTN | | OTN | | OTN |
|Switch |<- OTUk Link ->|Switch |<- OTUk Link ->|Switch |
| A | | B | | C |
+-------+ +-------+ +-------+
|<-- TE-Link -->| |<-- TE-Link -->|
Figure-1: OTUk TE-Link
3.2. ODUk TE-Link
When ODUk layer does not terminate on the same pair of nodes
as OTUk layer, ODUk link should be modeled as a TE-Link. As
bandwidth is directly managed on the ODUk link, associated OTUk
links are not significant in this case. Switching at ODUj layer
(including multi-stage multiplexing) can be managed on ODUk TE-Link.
Figure-2 below provides an illustration of this link type.
When a LO-ODU layer being switched on the ODUk interface involves
multi-stage multiplexing, all the HO-ODU layer(s) should necessarily
terminate between the same pair of nodes as ODUk in this case. For
example, if ODU1 layer switching is configured on an ODU3 link via
multiplexing hierarchy ODU3<-ODU2<-ODU1, HO-ODU (namely ODU2)
should terminate between the same pair of nodes as ODU3.
+-------+ +-------+ +-------+
| OTN | | OTN | | OTN |
|Switch |<- OTUk Link ->|Switch |<- OTUk Link ->|Switch |
| A | | B | | C |
+-------+ +-------+ +-------+
ODUk Switched
|<------------- ODUk Link ------------->|
|<-------------- TE-Link--------------->|
Figure-2: ODUk TE-Link
3.3. ODUj TE-Link
When a LO-ODUj within a HO-ODUk does not terminate on the same
pair of nodes as HO-ODUk layer, Separate TE-Links needs to be
modeled for ODUk link and ODUj link. Also, ODUk link shall
no longer manage the bandwidth associated with the ODUj link.
Switching at sub-ODUj layer (including multi-stage multiplexing)
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can be supported on this ODUj TE-Link. Figure-3 below provides
an illustration of this link type.
When a LO-ODU layer being switched on an ODUj interface involves
multi-stage multiplexing, all the HO-ODU layer(s) should necessarily
terminate between the same pair of nodes as ODUj in this case. For
example, if ODU0 layer switching is configured on an ODU2 link via
multiplexing hierarchy ODU2<-ODU1<-ODU0, HO-ODU (namely ODU1)
should terminate between the same pair of nodes as ODU2.
+-----+ +-----+ +-----+ +-----+
| OTN | | OTN | | OTN | | OTN |
| SW |<-OTUk Link->| SW |<-OTUk Link->| SW |<-OTUk Link->| SW |
| A | | B | | C | | D |
+-----+ +-----+ +-----+ +-----+
ODUj Switched ODUk Switched
|<--------- ODUk Link ---------->|
|<--------- TE-Link #1 --------->|
|<-------------------- ODUj Link ------------------->|
|<-------------------- TE-Link #2 ------------------>|
Figure-3: ODUj TE-Link
3.4. Bundled TE-Link
Any mix of OTU and ODU links of dissimilar rates that terminates on
same pair of nodes and meets the entire bundling criterion specified in
TE-Link Bundling specification [RFC4201] can be pulled together to
form a Bundle TE-Link. This is required for better scalability.
3.5. OTU/ODU Link Property Agreement
The OTN interfaces (associated with peer nodes) participating in a
TE-Link may not be fully compatible in terms of OTN interface
properties. The lowest common denominator between the two links
endpoints need to be used for forming the TE link. Some of OTN
specific link properties that need to be agreed upon between
the two link endpoints (on peer nodes) are:
(a) OPU Tributary Slot Granularity for OPU2 and OPU3.
(b) Multiplexing hierarchies supported - both number of stages and
specific LO-ODUs supported in each stage. This includes both
Fixed and Flexible ODU containers.
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These link properties either can be configured or discovered through
Link discovery mechanism. The details of such mechanism is beyond the
scope of this document.
4. OTU/ODU Link Bandwidth Model
Bandwidth allocation/management on OTU/ODU links is done in terms
of discrete units called OPU Tributary Slots. OPU Tributary Slots
occurs in two granularities (1.25Gbps and 2.5Gbps) and the actual
bit-rate of the OPU Tributary Slot slightly varies for different
ODU container types (i.e., ODU1, ODU2, ODU3 and ODU4). As a result
of this disparity, number of Tributary Slots required to map a
LO-ODU on different HO-ODU container types could vary. For example,
ODU2e requires 9 OPU TSs on ODU3 and 8 OPU TSs on ODU4.
The basic objectives of OTN interface bandwidth model are as
follows:
(a) Support ODU multi-stage multiplexing hierarchy and yet not
require advertisement of complete hierarchy tree.
(b) Account for bandwidth fragmentation that can result due to
the restricted multiplexing hierarchy supported on an OTN
interface. For example, assume that an ODU3 interface
supports direct multiplexing of ODU2 only. Here, mapping
of ODU1 and ODU0 is possible only through second stage
multiplexing underneath ODU2. If two ODU1 are created under
two different ODU2, only two ODU2 can be created further on
the interface although 28 Tributary Slots (1.25Gbps) are
available on the interface (ODU hierarchy).
(c) Hide the complexities in Tributary Slot Granularities (1.25Gbps
and 2.5Gbps) from bandwidth model and thereby simplify the
end-to-end path computation. As explained in the previous
section, this needs to be negotiated as a part of link
discovery or pre-configured locally on the either ends.
(d) Hide the complexities in Tributary Slot Size disparities (among
ODU containers) and number of Tributary Slots required to map
a LO-ODU. This can be achieved by advertising the number of
LO-ODU containers that can be mapped on an OTN interface rather
than number of Tributary Slots or absolute bandwidth in
bytes/sec.
(e) For ODU-Flex service, Absolute bandwidth required (for CBR
or GFP mapped service) needs to be mapped to 'n' Tributary
Slots of certain bit rate. This needs Tributary Slot bit-rate
and number of Tributary slots to be advertised.
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5. OSPF TE-LSA Extension
This section describes the OSPF TE-LSA Extensions to support
bandwidth encoding for OTU/ODU TE-Links.
5.1. Maximum Bandwidth
The format and interpretation of this attribute must be consistent
with OSPF-TE Extension [RFC3630] and TE-Link Bundling Support
[RFC4201] specifications. The OPUk payload nominal rate (in bytes
per sec) as specified in [G.709-v3] shall be encoded in this
attribute.
5.2. Maximum Reservable Bandwidth
The format and interpretation of this attribute must be consistent
with OSPF-TE Extension [RFC3630] and TE-Link Bundling Support
[RFC4201] specifications.
5.3. Unreserved Bandwidth
The format and interpretation of this attribute must be consistent
with OSPF-TE Extension [RFC3630] and TE-Link Bundling Support
[RFC4201] specifications.
Unreserved Bandwidth in bytes per second is not of much value for
OTU/ODU interfaces. Unreserved Bandwidth per ODU rate is more
appropriate and useful in this case. Implementations may choose to
ignore this attribute and consider per ODU-rate Unreserved Bandwidth
defined in Interface Switch Capability Descriptor for "G.709 ODUk"
encoding type. See section 5.4.1 for details.
5.4. Interface Switch Capability Descriptor
The Interface Switching Capability Descriptor describes switching
capability of an interface [RFC 4202]. This document defines a new
Switching Capability value for OTN [G.709-v3] as follows:
Value Type
----- ----
250 OTN-TDM capable (OTN-TDM)
Nodes advertising ODUk switching BW for for its links must use
Switching Type and Encoding values as follows:
Switching Type = OTN-TDM
Encoding Type = G.709 ODUk (Digital Path) [as defined in RFC4328]
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Both fixed ODUk (where k=0,1,2,3,4,1e,2e) and flexible ODUs (ODUflex)
use same switching type and encoding values.
When Swithcing Type and Encoding fields are set to values as stated
above, the Interface Switching Capability Descriptor should be
interpreted 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Switching Cap | Encoding | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Max LSP Bandwidth at priority 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Max LSP Bandwidth at priority 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Max LSP Bandwidth at priority 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Max LSP Bandwidth at priority 3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Max LSP Bandwidth at priority 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Max LSP Bandwidth at priority 5 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Max LSP Bandwidth at priority 6 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Max LSP Bandwidth at priority 7 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ODUk - Switch Capability Specific Information |
| (variable length) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Maximum LSP Bandwidth
This field should be encoded with Nominal Rate of the ODUj (j<= k) for
which Bandwidth is advertised. The bandwidth unit is in bytes per second &
the encoding is in IEEE floating point format [RFC 3471]. The discrete values
for varous ODUj(s) is shown in the table below.
For an unbundled link, the Maximum LSP Bandwidth at priority 'p' is set to
Nominal rate of the ODUj for which bandwidth is advertised in Switch
Capability Specific Information (SCSI).
For bundled link too, the Maximum LSP Bandwidth at priority 'p' is set to
Nominal rate of the ODUj for which bandwidth is advertised in Switch
Capability Specific Information (SCSI).
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ODU type Nomial Rate(bytes/s) Value in Byes/Sec (IEEE format)
----------- ----------------- ------------------------------
ODU0 15552000
ODU1 312346890.75
ODU2 1254659240.50
ODU2e 1299940664.50
ODU1e
ODU3 5039902372.875
ODU4 13099305726.875
ODUflex Any
The Maximum LSP bandwidth field is used to identify the ODUj type.
5.4.1 ODU Switching
When Switching Capability is set to OTN-TDM, it means the node is capable of
- terminating OTUk layer
- Switching of HO-ODU (ODUk)
- switching of LO-ODU (ODUj) if HO-ODU supports mux/demux
(termination of HO-ODU is required for mux/demux operation)
Multiple ISCDs would be advertised if an interface supports more than one
type of ODUk switching. There would be one ISCD advertisement per ODUj
independent of the OTN multiplexing branch it belongs to.
For e.g. If an OTU3 interface supports ODU0, ODU1 and ODU2 switching, there
would be three ISCDs one for each ODU type.
Refer to examples in section 7.0.
5.4.2. ODUk Switch Capability Specific Information
This SCSI field contains bandwidth information for fixed
ODUj(j=0,1,2,3,4,2e,1e) or ODUflex.
The type of ODUj/ODuflex is identified by Maximum LSP bandwidth field and
BW sub TLV Type field as follows.
If bandwidth advertisement is for fixed size ODUj, then
- set BW sub TLV Type = 1
- Encode nominal rate of the ODUj in Max LSP BW field
- Encode avaialble number of ODUj(s) as shown below
If bandwidth advertisment is for ODUflex, then
- set BW sub TLV Type = 2
- Encode available BW in Max LSP BW field
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- Encode avaialble Bandwidth as shown below
The SCSI field must be included when Switching Capability is "OTN-TDM".
5.4.2.1 Bandwidth sub TLV for fixed ODUj
The format of Bandwidth sub TLV for fixed size ODUj is shown below;
(j=0,1,2,3,4,2e,1e). The TLV Type must be set to 1 for fixed ODUs.
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=1 (for fixed ODUj) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available ODUj count at priority 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available ODUj count at priority 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available ODUj count at priority 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available ODUj count at priority 3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available ODUj count at priority 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available ODUj count at priority 5 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available ODUj count at priority 6 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available ODUj count at priority 7 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Available ODUj(s):
This field (32 bits) indicates the maximum number of Containers
of a given ODUj-Type at priority 'p' available on this TE-Link.
The "Available ODUj(s)" of a bundled link at priority p is defined
to be the sum of "Available ODUj(s)" at priority p of all of its
component links.
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5.4.2.2 Bandwidth sub-TLV for ODUflex
The format of Bandwidth sub TLV for ODUflex is shown below.
The TLV Type is set to 2 for flexible ODUs.
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=2 (for ODUflex) | length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available ODUflex BW in bytes/sec priority 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available ODUflex BW in bytes/sec priority 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available ODUflex BW in bytes/sec priority 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available ODUflex BW in bytes/sec priority 3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available ODUflex BW in bytes/sec priority 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available ODUflex BW in bytes/sec priority 5 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available ODUflex BW in bytes/sec priority 6 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available ODUflex BW in bytes/sec priority 7 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Available BW (in bytes/sec)
Available BW (in bytes/sec) is represented in IEEE float-point
format similar to Max-Lsp-Bandwidth in ISCD.
The "Available BW" of a bundled link at priority p is defined
to be the sum of "Available BW" at priority p of all of its
component links.
This information may be used to route LSPs over links which
have most bandwidth available.
5.5. Interface Multiplexing Capability Descriptor
The OTN multiplexing hierarchy involves one or more ODU layers. The
server ODU layer is called the higher order ODU(HO-ODU) and the layer
multiplexed into a server ODU layer is called lower order ODU (LO-ODU).
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A HO-ODU can carry (mux/demux) one or more LO-ODUs as specified in G.709.
Termination of HO-ODU is necessary to mux/demux LO-ODUs. For e.g.
a) on a OTU2 interface with OTU2-ODU2-ODU0 muxing stack,
it is necessary to terminate ODU2(H) in order to mux/demux
contained ODU0s.
b) on a OTU2 interface with OTU2-ODU2-ODU1-ODU0 muxing stack,
it is necessary to terminate ODU2 and ODU1 layers to mux/demux
contained ODU0s.
An OTN interface supporting multi-stage multiplexing requires termination
of more than one HO-ODU to access one or more LO-ODUs for switching purposes.
For e.g. on an interface with OTU3-ODU3-ODU2-ODU0 multiplexing stack/hierarchy,
ODU3 and ODU2 layers should be terminated to access ODU0s for switching purposes.
5.5.1 Multiplex Layers and Hierarchical LSP
It is possible to construct H-LSP(s) using different HO-ODU muxing layer(s).
While creation of H-LSP is optional, it becomes necessary in network
scenarios where switching restrictions exist for LO-ODUs.
Example #1:
- Nodes A, B, D & E are ODU0 and ODU2 switching capable;
- Nodes C is ODU2 switching capable only.
An ODU2-FA between nodes B & D is necessary to support E2E ODU0-LSP(s)
A-----B---------C--------D-----E
<-----ODU2-FA------>
<------------ODU0-LSP -------->
Example #2: ODU0-LSP over G.709-v1 capable node (legacy node)
- Nodes A, B, D & E are ODU0 & ODU1 switch capable nodes;
- Node C is ODU1 switching capable
An ODU1-FA between nodes B & D is necessary to support E2E ODU0-LSPs
A-----B---------C--------D-----E
<-----ODU1-FA------>
<------------ODU0-LSP -------->
In order to support identification of potential FA boundary points, it is
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necessary to flood mux/demux information. This includes information about:
- the HO-ODU layer which can be terminated
- the LO-ODUs available upon HO-ODU termination (muxing hierarchy)
The multiplexing hierarchy provides information about
specific branch(es) of the OTN muxing hierarchy. This includes
- one or more HO-ODU(s) which needs to be terminated and
- a LO-ODU layer which can be accessed after termination
The HO-ODUs which are terminate-able are potential FA end points.
FA becomes necessary when switching bandwidth is not available at all
nodes along the path for an LSP (specifically for LSPs at LO-ODU layers).
This draft proposes the use of IMCD (Interface Multiplexing Capability
Descriptor) to distribute OTN mux/demux information of Te-end points.
5.5.2 IMCD format
The Interface Multiplexing Capability Descriptor (IMCD) describes
"Multiplexing" capability of an interface. It is a sub-TLV of the
Link TLV (Type TBD). The format of value field is as shown below:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| G-PID | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available HO-ODUj count at priority 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available HO-ODUj count at priority 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available HO-ODUj count at priority 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available HO-ODUj count at priority 3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available HO-ODUj count at priority 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available HO-ODUj count at priority 5 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available HO-ODUj count at priority 6 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available HO-ODUj count at priority 7 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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5.5.2.1 G-PID
The G-PID field is a 16 bit field as defined in [RFC3471].
New G-PID values are defined in addition to those defined in [RFC3471].
Within OTN context, the new G-PID values identify multiplexing stack
supported by the Te-end point.
The table below shows newly defined values for G-PID:
Value G-PID Meaning
----- ------ ----------------------------
60 ODU1-ODU0 ODU1 termination required
61 ODU2-ODU0 ODU2 termination required
62 ODU2-ODU1 ODU2 termination required
63 ODU2-ODU1-ODU0 ODU2 & ODU1 termination required
64 ODU2-ODUflex ODU2 termination required
65 ODU3-ODU0 ODU3 termination required
66 ODU3-ODU1 ODU3 termination required
67 ODU3-ODU1-ODU0 ODU3 & ODU1 termination required
68 ODU3-ODU2 ODU3 termination required
69 ODU3-ODU2-ODU0 ODU3 & ODU2 termination required
70 ODU3-ODU2-ODU1 ODU3 & ODU2 termination required
71 ODU3-ODU2-ODU1-ODU0 ODU3 & ODU2 & ODU1 termination required
72 ODU3-ODU2-ODUflex ODU3 & ODU2 termination required
73 ODU3-ODUflex ODU3 termination required
74 ODU3-ODU2e ODU3 termination required
75 ODU4-ODU0 ODU4 termination required
76 ODU4-ODU1 ODU4 termination required
77 ODU4-ODU1-ODU0 ODU4 & ODU1 termination required
78 ODU4-ODU2 ODU4 termination required
79 ODU4-ODU2-ODU0 ODU4 & ODU2 termination required
80 ODU4-ODU2-ODU1 ODU4 & ODU2 termination required
81 ODU4-ODU2-ODU1-ODU0 ODU4 & ODU2 & ODU1 termination required
82 ODU4-ODU2-ODUflex ODU4 & ODU2 termination required
83 ODU4-ODU3 ODU4 termination required
84 ODU4-ODU3-ODU0 ODU4 & ODU3 termination required
85 ODU4-ODU3-ODU1 ODU4 & ODU3 termination required
86 ODU4-ODU3-ODU1-ODU0 ODU4 & ODU3 & ODU1 termination required
87 ODU4-ODU3-ODU2 ODU4 & ODU3 termination required
88 ODU4-ODU3-ODU2-ODU0 ODU4 & ODU3 & ODU2 termination required
89 ODU4-ODU3-ODU2-ODU1 ODU4 & ODU3 & ODU2 termination required
90 ODU4-ODU3-ODU2-ODU1-ODU0 ODU4 & ODU3 & ODU2 & ODU1 termination
required
91 ODU4-ODU3-ODU2-ODUflex ODU4 & ODU3 & ODU2 termination required
92 ODU4-ODU3-ODUflex ODU4 & ODU3 termination required
93 ODU4-ODU3-ODU2e ODU4 & ODU3 termination required
94 ODU4-ODUflex ODU4 termination required
95 ODU4-ODU2e ODU4 termination required
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96 ODU1 ODU1 termination required
97 ODU2 ODU2 termination required
98 ODU3 ODU3 termination required
99 ODU4 ODU4 termination required
100 ODU2-GFP-10GBE ODU2 termination for Ethernet
101 ODU2e-10GBE ODU2e termination for Ethernet
102 ODU2-OC192 ODU2 termination for SONET
5.5.2.2 Available Bandwidth
The available bandwidth advertised in "Available HO-ODUj" field
indicates the number of "Terminations" possible at HO-ODUj layer.
The HO-ODUj layer (Parent ODU) is identified by G-PID field.
This field (32 bits) indicates maximum number of Containers
of a given HO-ODUj at priority 'p' available on the TE-Link;
where {j=1,2,3,4}.
The "Available HO-ODUj(s)" of a bundled link at priority 'p' is
defined to be the sum of "Available HO-ODUj(s)" at priority 'p' of all
of its component links for that specific G-PID.
Example#1: Unbundled link with ODU2-ODU0 muxing hierarchy support
A ---------- B
IMCD advertised would be as follows:
o G-PID= ODU2-ODU0
o Available HO-ODUj count = 1 ( refers to ODU2 layer)
The ODU2 termination implies ability to mux/demux 8xODU0s.
Example#2: Bundled Te-link with ODU2-ODU0 muxing hierarchy support (3 links)
A ========== B
IMCD advertised would be as follows:
o G-PID= ODU2-ODU0
o Available HO-ODUj count = 3 (refers to ODU2 layer)
The ODU2 termination implies ability to mux/demux 24xODU0s in total.
5.5.3 Controlling IMCD advertisement
The IMCD advertisement is not mandatory and it is required only
when FA support is needed.
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The network operators can selectively enable IMCD advertisement
for specific HO-ODU mux layer(s). This can be done on a
link by link basis, node basis or network basis. The mechanism
to achieve this is outside the scope of this document.
5.5.4 How to use IMCDs for FA creation
When computing path for an FA (induced or otherwise), the path
computing node should look for matching G-PIDs at the FA boundary nodes.
For example, to create ODU1-FA for ODU0 service, the path computation
should look for matching G-PID = ODU1-ODU0 at nodes B & D
The need for FA is due to Node-C's ability to switch ODU1 only.
A-----B---------C--------D-----E
<-----ODU1-FA------>
<------------ODU0-LSP -------->
5.5.5 IMCD and non OTN services
In certain deployments it may be beneficial to advertise ODU
termination bandwidth without the LO-ODU information. The intent is to
allow signaling to decide non-OTN signal to adapt at the time
of path establishment.
The G-PID values 96, 97, 98, 99 defined in section 5.5.2.1 are meant for
this purpose.
The path computation can also be preformed for specific clients over
an ODUj using G-PID values 100, 101 & 102 (e.g. 10GBE mapping to
ODU2 using GFP).
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6. Examples
This sections presents some use-cases for bandwidth encoding
and usage.
6.1. Network with no IMCD advertisement (no FA support)
A-------B------C------D-----E
Suppose Muxing Hierarchy supported at the end points as shown:
Link A-B: Mux hierarchy at A & B ends is as follows:
ODU1 ODU0
\ /
\ /
ODU2
|
OTU2
Link B-C: Mux hierarchy at B & C ends is as follows:
ODU0
|
ODU1 ODU0
\ /
\ /
ODU2
|
OTU2
Link C-D: mux hierarchy at C & D ends is as follows:
ODU0
|
ODU1
|
ODU2
|
OTU2
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a) The ISCD advertisement by nodes A, B, C & D would be as follows
ISCD1:
Max LSP BW = ODU2 nominal rate in bytes/sec
Available ODU2 count at priority 'p' = 1
ISCD2:
Max LSP BW = ODU1 nominal rate in bytes/sec
Available ODU1 count at priority 'p' = 4
ISCD3:
Max LSP BW = ODU0 nominal rate in bytes/sec
Available ODU0 count at priority 'p' = 8
b) BW advertisement after an ODU0-LSP creation from A to D.
The bandwidth is no longer available at ODU2 rate.
ISCD1:
Max LSP BW = ODU1 nominal rate in bytes/sec
Available ODU1 count at priority 'p' = 3
ISCD2:
Max LSP BW = ODU0 nominal rate in bytes/sec
Available ODU0 count at priority 'p' = 7
6.2. Network with IMCD advertisement for FA support
A-------B------C------D-----E
<---ODU1-FA--->
<---------- ODU0-LSP ------->
The above network can support FA at ODU2 and ODU1 layers.
To support FA origination/termination, the IMCDs would be advertised
as follows. This is in addition to ISCD advertisement.
The ISCD1, ISCD2 & ISCD3 advertisement by A, B, C & D is same as in section 7.1
The IMCD advertisement by A & B for link A-B:
IMCD1:
G-PID = ODU2-ODU1
Available HO-ODUj count at Pi = 1 (ODU2)
IMCD2:
G-PID = ODU2-ODU0
Available HO-ODUj count at Pi = 1 (ODU2)
The IMCD advertisement by B & C for link B-C:
IMCD1:
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G-PID = ODU2-ODU1
Available HO-ODUj count at Pi = 1 (ODU2)
IMCD2:
G-PID = ODU2-ODU0
Available HO-ODUj count at Pi = 1 (ODU2)
IMCD3:
G-PID = ODU1-ODU0
Available HO-ODUj count at Pi = 4 (ODU1)
The IMCDs advertised by C & D for link C-D would be as follows:
IMCD1:
G-PID = ODU2-ODU1
Available HO-ODUj count at Pi = 1 (ODU2)
IMCD2:
G-PID = ODU2-ODU1-ODU0
Available HO-ODUj count at Pi = 1 (ODU2)
IMCD3:
G-PID = ODU1-ODU0
Available HO-ODUj count at Pi = 4 (ODU1)
The IMCD advertisement by B & C for link B-C after ODU1-FA creation:
IMCD1:
G-PID = ODU1-ODU0
Available HO-ODUj count at Pi = 3 (ODU1)
The IMCD advertisement by C & D for link C-D after ODU1-FA creation:
IMCD1:
G-PID = ODU1-ODU0
Available HO-ODUj count at Pi = 3 (ODU1)
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6.3. Link bundle with similar muxing capabilities
Consider a Bundled Te-link with 2xOTU3 links between Nodes A & B with
multiplexing hierarchy as shown:
ODU1 ODU0
\ / ODU0
\ / |
ODU2 ODU1 ODU0 ODUflex
| / / /
----------------
|
ODU3
|
OTU3
A ===================== B
The ISCDs and IMCDs advertised by A & B would be as follows:
ISCD1:
Max LSP BW = ODU3 nominal rate in bytes/sec
Available ODU3 count at priority 'p' = 2
ISCD2:
Max LSP BW = ODU2 nominal rate in bytes/sec
Available ODU2 count at priority 'p' = 8
ISCD3:
Max LSP BW = ODU1 nominal rate in bytes/sec
Available ODU1 count at priority 'p' = 32
ISCD4:
Max LSP BW = ODU0 nominal rate in bytes/sec
Available ODU0 count at priority 'p' = 64
ISCD5:
Max LSP BW = ODU3 nominal rate in bytes/sec
Available ODUflex BW = 2xODU3 BW in byte/sec
To support FAs at ODU3, ODU2 & ODU1 rates, the following IMCDs are advertised
IMCD1:
G-PID = ODU3-ODU2
Available HO-ODUj count at Pi = 2 (ODU3)
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IMCD2:
G-PID = ODU3-ODU2-ODU1
Available HO-ODUj count at Pi = 2 (ODU3)
IMCD3:
G-PID = ODU3-ODU2-ODU0
Available HO-ODUj count at Pi = 2 (ODU3)
IMCD4:
G-PID = ODU3-ODU1
Available HO-ODUj count at Pi = 2 (ODU3)
IMCD5:
G-PID = ODU3-ODU1-ODU0
Available HO-ODUj count at Pi = 2 (ODU3)
IMCD6:
G-PID = ODU3-ODU0
Available HO-ODUj count at Pi = 2 (ODU3)
IMCD7:
G-PID = ODU2-ODU1
Available HO-ODUj count at Pi = 8 (ODU2)
IMCD8:
G-PID = ODU2-ODU0
Available HO-ODUj count at Pi = 8 (ODU2)
IMCD9:
G-PID = ODU1-ODU0
Available HO-ODUj count at Pi = 32 (ODU1)
IMCD9:
G-PID = ODU3-ODUflex
Available HO-ODUj count at Pi = 3 (ODUflex)
6.4. Link bundle with dissimilar muxing capabilities: Layer relation
A---------B---------C--------D-------E
|------ODU2-FA-----|
|------ODU1-FA-------------|
|----------------ODU0-LSP------------|
Link A-B: Hierarchy at both ends is OTU2-ODU2-ODU0
Link B-C: Is a bundled Te-link with 3 component links with
multiplexing hierarchy at both ends as shown:
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Component link#1: OTU2 link with mux hierarchy: OTU2-ODU2-ODU1-ODU0
Component link#2: OTU2 link with mux hierarchy: OTU2-ODU2-ODU1
Component link#3: OTU1 link with mux hierarchy: OTU1-ODU1-ODU0
Link C-D:
- Hierarchy at C end is OTU2-ODU2
- Hierarchy at D end is OTU2-ODU2-ODU1
Link D-E:
- Hierarchy at D end is OTU1-ODU1
- Hierarchy at E end is OTU1-ODU1-ODU0
The IMCDs advertised for B-C would include the following:
IMCD1:
G-PID = ODU2-ODU1
Available HO-ODUj count at Pi = 2 (ODU2)
IMCD2:
G-PID = ODU1-ODU0
Available HO-ODUj count at Pi = 5 (ODU1)
IMCD3:
G-PID = ODU2-ODU1-ODU0
Available HO-ODUj count at Pi = 1 (ODU2)
In this example, we need two FAs to originate from the same point (at node-B).
It is necessary to advertise IMCD3 as we can not conclude full mux
relation from IMCD1 & IMCD2.
7. Backward Compatibility
If backwards compatibility is required with G.709-v1, then [RFC4328]
based ISCDs should be a advertised in addition to ISCDs/IMCDs specified
in this document.
8. Security Considerations
There are no additional security implications to OSPF routing
protocol due to the extensions captured in this document.
9. IANA Considerations
The memo introduces two new sub-TLVs of the Interface Switch Capability
Descriptor Sub-TLV of TE-LSA. [RFC3630] says that the sub-TLVs of the
TE Link TLV in the range 10-32767 must be assigned by Expert Review,
and must be registered with IANA.
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10. References
10.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels".
[RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
(TE) Extensions to OSPF Version 2", RFC 3630
[RFC3471] Berger, L., "Generalized Multi-Protocol Label Switching
(GMPLS) Signaling Functional Description", RFC 3471,
January 2003.
[RFC4201] Kompella, K., Rekhter, Y., and L. Berger, "Link Bundling in
MPLS Traffic Engineering (TE)"
[RFC4203] Kompella, K. and Y. Rekhter, "OSPF Extensions in Support of
Generalized Multi-Protocol Label Switching (GMPLS)"
[RFC4204] Lang, J., Ed., "Link Management Protocol (LMP)", RFC
4204, October 2005.
[RFC4328] Papadimitriou, D., "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Extensions for G.709 Optical
Transport Networks Control", RFC 4328, January 2006.
[RFC5212] Shiomoto, K., Papadimitriou, D., Le Roux, JL., Vigoureux,
M., and D. Brungard, "Requirements for GMPLS-Based
Multi-Region and Multi-Layer Networks (MRN/MLN)", RFC
5212, July 2008.
[RFC5339] Le Roux, JL. and D. Papadimitriou, "Evaluation of Existing
GMPLS Protocols against Multi-Layer and Multi-Region
Networks (MLN/MRN)", RFC 5339, September 2008.
[RFC6001] D. Papadimitriou, et al, Generalized MPLS (GMPLS)
Protocol Extensions for Multi-Layer and Multi-Region Networks (MLN/MRN)
[G.709-v3] ITU-T, "Interfaces for the Optical Transport Network
(OTN)", G.709 Recommendation, December 2009.
[GSUP.43] ITU-T, "Proposed revision of G.sup43 (for agreement)",
December 2008.
10.2. Informative References
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[RFC3945] Mannie, E., "Generalized Multi-Protocol Label Switching
(GMPLS) Architecture", RFC 3945, October 2004.
[G.709-v1] ITU-T, "Interface for the Optical Transport Network
(OTN)," G.709 Recommendation (and Amendment 1), February
2001 (October 2001).
[G.872] ITU-T, "Architecture of optical transport networks",
November 2001 (11 2001).
[G.709-FRAME] F. Zhang, D. Li, H. Li, S. Belotti, "Framework for
GMPLS and PCE Control of G.709 Optical Transport
Networks", draft-zhang-ccamp-gmpls-g709-framework-02,
work in progress.
[WSON-FRAME] Y. Lee, G. Bernstein, W. Imajuku, "Framework for GMPLS
and PCE Control of Wavelength Switched Optical Networks
(WSON)", draft-ietf-ccamp-rwa-wson-framework, work in
progress.
11. Acknowledgements
Special thanks to Daniele Ceccarelli, Lyndon Ong, Sergio Belotti,
Pietro Grandi, Jonathan Sadler, Remi Theillaud, Fatai Zhang and
Diego Caviglia for discussions on various modeling options.
Authors would like to thank Lou Berger,Ping Pan, Radhakrishna
Valiveti and Mohit Misra for review comments and suggestions.
Author's Addresses
Ashok Kunjidhapatham
Infinera Corporation
169, Java Drive
Sunnyvale, CA-94089
USA
Email: akunjidhapatham@infinera.com
Rajan Rao
Infinera Corporation
169, Java Drive
Sunnyvale, CA-94089
USA
Email: rrao@infinera.com
Snigdho Bardalai
Infinera Corporation
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169, Java Drive
Sunnyvale, CA-94089
USA
Email: sbardalai@infinera.com
Khuzema Pithewan
Infinera Corporation
169, Java Drive
Sunnyvale, CA-94089
USA
Email: kpithewan@infinera.com
Biao Lu
Infinera Corporation
169, Java Drive
Sunnyvale, CA-94089
USA
Email: blu@infinera.com
John Drake
Juniper Networks
USA
Email: jdrake@juniper.net
Steve Balls
Metaswitch Networks
100 Church Street
Enfield
EN2 6BQ U.K.
Email: steve.balls@metaswitch.com
Xihua Fu,
ZTE
China
fu.xihua@zte.com.cn
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Appendix A: Abbreviations & Terminology
A.1 Abbreviations:
CBR Constant Bit Rate
GFP Generic Framing Procedure
HO-ODU Higher Order ODU
LSC Lambda Switch Capable
LSP Label Switched Path
LO-ODU Lower Order ODU
ISCD Interface Switch Capability Descriptor
OCC Optical Channel Carrier
OCG Optical Carrier Group
OCh Optical Channel (with full functionality)
OChr Optical Channel (with reduced functionality)
ODTUG Optical Date Tributary Unit Group
ODU Optical Channel Data Unit
OMS Optical Multiplex Section
OMU Optical Multiplex Unit
OPS Optical Physical Section
OPU Optical Channel Payload Unit
OSC Optical Supervisory Channel
OTH Optical Transport Hierarchy
OTM Optical Transport Module
OTN Optical Transport Network
OTS Optical Transmission Section
OTU Optical Channel Transport Unit
OTUkV Functionally Standardized OTUk
SCSI Switch Capability Specific Information
TDM Time Division Multiplex
A.2 Terminology
1. ODUk and ODUj
ODUk refers to the ODU container that is directly mapped to an
OTU container. ODUj refers to the lower order ODU container that
is mapped to an higher order ODU container via multiplexing.
2. LO-ODU and HO-ODU
LO-ODU refers to the ODU client layer of lower rate that is mapped
to an ODU server layer of higher rate via multiplexing. HO-ODU
refers to the ODU server layer of higher rate that supports
mapping of one or more ODU client layers of lower rate.
In multi-stage multiplexing case, a given ODU layer can be a
client for one stage (interpreted as LO-ODU) and at the same
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time server for another stage (interpreted as HO-ODU). In this
case, the notion of LO-ODU and HO-ODU needs to be interpreted in a
recursive manner.
ODU0 | (LO-ODU)
| |
| | Stage #1
V |
(LO-ODU) | ODU1 | (HO-ODU)
| |
Stage #2 | |
| V
(HO-ODU) | ODU2 | (LO-ODU)
| |
| | Stage #3
V |
ODU3 | (HO-ODU)
Figure-4 : LO-ODU and HO-ODU
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Internet-Draft draft-ashok-ccamp-gmpls-ospf-g709-03.txt March 14, 2011
Appendix B : Optimization Techniques
Optimization techniques can be used to reduce TE-LSA size. The following
sub sections describe available options.
B.1 Multiple ISCDs Vs. Single ISCD
It is possible to encode ISCDs corresponding to different ODU layers
into SCSI field of a single ISCD. This options was shown in previous
version of this draft (draft-ashok-ccamp-gmpls-ospf-g709-02).
Doing so will reduce the LSA size by a factor of:
10 words x (#ODUjs - 1)
It is possible to reduce LSA size further by reducing the size of BW field
to half word. Doing so will reduce LSA size by a factor of:
4 words x (#ODUjs)
B.1 Multiple IMCDs Vs. Single IMCD
This optimization doesn't save much. The shrinking of BW field to 1/2 word
helps reduce LSA size to some extent. The size reduction depends on the number of ODUs supported.
4 words x (#ODUjs)
B.1 Eight priorities Vs. restricted number of priorities
It is possible to further optimize by advertising BW only for supported
priorities. This can be easily achieved by having a bit vector as described
in previous version of this draft.
Appendix C: Relation with MLN & MRN
The ISCD and IMCDs defined in this draft doesn't repalce IACDs.
All three (ISCD, IMCD & IACD) can co-exist in a network and
serve different purposes.
Appendix D : AMP, BMP & GMP Mapping
The G.709 defines various mapping schemes for LO-ODUs into HO-ODUs.
From G.709 descriptions, the AMP & GMP mapping appears to be fixed for
a given LO-ODU to HO-ODU based on the time slot granularity.
Since the mapping is fixed we do not see value in advertising this
information in TE-LSAs.
Rajan Rao, et al. Expires September 15, 2011 [Page 30]