RFC7138

Internet Engineering Task Force (IETF) D. Ceccarelli, Ed. Request for Comments: 7138 Ericsson Category: Standards Track F. Zhang ISSN: 2070-1721 Huawei Technologies

                                                          S. Belotti
                                                      Alcatel-Lucent
                                                              R. Rao
                                                Infinera Corporation
                                                            J. Drake
                                                             Juniper
                                                          March 2014

             Traffic Engineering Extensions to OSPF
 for GMPLS Control of Evolving G.709 Optical Transport Networks

Abstract

This document describes Open Shortest Path First - Traffic Engineering (OSPF-TE) routing protocol extensions to support GMPLS control of Optical Transport Networks (OTNs) specified in ITU-T Recommendation G.709 as published in 2012. It extends mechanisms defined in RFC 4203.

Status of This Memo

This is an Internet Standards Track document.

This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 5741.

Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc7138.

Copyright Notice

Copyright (c) 2014 IETF Trust and the persons identified as the document authors. All rights reserved.

This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.

       4.1.1. Switching Capability Specific Information

       4.1.2. Switching Capability Specific Information

       4.1.3. Switching Capability Specific Information --

  5.7. Example of Component Links with Non-Homogeneous

Introduction

G.709 ("Interfaces for the Optical Transport Network (OTN)") [G.709-2012] includes new fixed and flexible ODU (Optical channel Data Unit) containers, includes two types of tributary slots (i.e., 1.25 Gbps and 2.5 Gbps), and supports various multiplexing relationships (e.g., ODUj multiplexed into ODUk (j<k)), two different tributary slots for ODUk (K=1, 2, 3), and the ODUflex service type. In order to advertise this information in routing, this document provides encoding specific to OTN technology for use in GMPLS OSPF-TE as defined in RFC4203.

For a short overview of OTN evolution and implications of OTN requirements on GMPLS routing, please refer to RFC7062. The information model and an evaluation against the current solution are provided in RFC7096. The reader is supposed to be familiar with both of these documents.

Routing information for Optical Channel (OCh) layer (i.e., wavelength) is beyond the scope of this document. Please refer to RFC6163 and RFC6566 for further information.

Terminology

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.

OSPF-TE Extensions

In terms of GMPLS-based OTN networks, each Optical channel Transport Unit-k (OTUk) can be viewed as a component link, and each component link can carry one or more types of ODUj (j<k).

Each TE-Link State Advertisement (LSA) can carry a top-level link TLV with several nested sub-TLVs to describe different attributes of a TE-Link. Two top-level TLVs are defined in RFC3630: (1) The Router Address TLV (referred to as the Node TLV) and (2) the TE-Link TLV. One or more sub-TLVs can be nested into the two top-level TLVs. The sub-TLV set for the two top-level TLVs are also defined in RFC3630 and RFC4203.

As discussed in RFC7062 and RFC7096, OSPF-TE must be extended to be able to advertise the termination and Switching Capabilities of each different ODUj and ODUk/OTUk (Optical Transport Unit) and the advertisement of related multiplexing capabilities. These capabilities are carried in the Switching Capability specific information field of the Interface Switching Capability Descriptor

(ISCD) using formats defined in this document. As discussed in RFC7062, the use of a technology-specific Switching Capability specific information field necessitates the definition of a new Switching Capability value and associated new Switching Capability.

In the following, we will use ODUj to indicate a service type that is multiplexed into a higher-order (HO) ODU, ODUk to indicate a higher- order ODU including an ODUj, and ODUk/OTUk to indicate the layer mapped into the OTUk. Moreover, ODUj(S) and ODUk(S) are used to indicate the ODUj and ODUk supporting Switching Capability only, and the ODUj->ODUk format is used to indicate the ODUj-into-ODUk multiplexing capability.

This notation can be repeated as needed depending on the number of multiplexing levels. In the following, the term "multiplexing tree" is used to identify a multiplexing hierarchy where the root is always a server ODUk/OTUk and any other supported multiplexed container is represented with increasing granularity until reaching the leaf of the tree. The tree can be structured with more than one branch if the server ODUk/OTUk supports more than one hierarchy.

For example, if a multiplexing hierarchy like the following one is considered:

         ODU2 ODU0    ODUflex ODU0
            \ /            \ /
             |              |
           ODU3           ODU2
              \            /
               \          /
                \        /
                 \      /
                   ODU4

the ODU4 is the root of the muxing tree; ODU3 and ODU2 are containers directly multiplexed into the server; and ODU2 and ODU0 are the leaves of the ODU3 branch, while ODUflex and ODU0 are the leaves of the ODU2 one. This means that it is possible to have the following multiplexing capabilities:

   ODU2->ODU3->ODU4
   ODU0->ODU3->ODU4
   ODUflex->ODU2->ODU4
   ODU0->ODU2->ODU4

TE-Link Representation

G.709 ODUk/OTUk links are represented as TE-Links in GMPLS Traffic Engineering Topology for supporting ODUj layer switching. These TE- Links can be modeled in multiple ways.

OTUk physical link(s) can be modeled as a TE-Link(s). Figure 1 below provides an illustration of one-hop OTUk TE-Links.

       +-------+               +-------+               +-------+
       |  OTN  |               |  OTN  |               |  OTN  |
       |Switch |<- OTUk Link ->|Switch |<- OTUk Link ->|Switch |
       |   A   |               |   B   |               |   C   |
       +-------+               +-------+               +-------+

               |<-- TE-Link -->|       |<-- TE-Link -->|

                      Figure 1: OTUk TE-Links

It is possible to create TE-Links that span more than one hop by creating forwarding adjacencies (FAs) between non-adjacent nodes (see Figure 2). As in the one-hop case, multiple-hop TE-Links advertise the ODU Switching Capability.

       +-------+               +-------+               +-------+
       |  OTN  |               |  OTN  |               |  OTN  |
       |Switch |<- OTUk Link ->|Switch |<- OTUk Link ->|Switch |
       |   A   |               |   B   |               |   C   |
       +-------+               +-------+               +-------+
                             ODUk Switched

               |<------------- ODUk Link ------------->|
               |<-------------- TE-Link--------------->|

                  Figure 2: Multiple-Hop TE-Link

ISCD Format Extensions

The ISCD describes the Switching Capability of an interface and is defined in RFC4203. This document defines a new Switching Capability value for OTN [G.709-2012] as follows:

Value Type

---

----

110 OTN-TDM capable

When supporting the extensions defined in this document, for both fixed and flexible ODUs, the Switching Capability and Encoding values MUST be used as follows:

o Switching Capability = OTN-TDM

o Encoding Type = G.709 ODUk (Digital Path) as defined in RFC4328

The same Switching Type and encoding values must be used for both fixed and flexible ODUs. When Switching Capability and Encoding fields are set to values as stated above, the Interface Switching Capability Descriptor MUST be interpreted as defined in RFC4203.

The MAX LSP Bandwidth field is used according to RFC4203, i.e., 0 <= MAX LSP Bandwidth <= ODUk/OTUk, and intermediate values are those on the branch of the OTN switching hierarchy supported by the interface. For example, in the OTU4 link it could be possible to have ODU4 as MAX LSP Bandwidth for some priorities, ODU3 for others, ODU2 for some others, etc. The bandwidth unit is in bytes/second and the encoding MUST be in IEEE floating point format. The discrete values for various ODUs are shown in the table below (please note that there are 1000 bits in a kilobit according to normal practices in telecommunications).

+-------------------+-----------------------------+-----------------+ | ODU Type | ODU nominal bit rate |Value in Byte/Sec| | | |(floating p. val)| +-------------------+-----------------------------+-----------------+ | ODU0 | 1,244,160 kbps | 0x4D1450C0 | | ODU1 | 239/238 x 2,488,320 kbps | 0x4D94F048 | | ODU2 | 239/237 x 9,953,280 kbps | 0x4E959129 | | ODU3 | 239/236 x 39,813,120 kbps | 0x4F963367 | | ODU4 | 239/227 x 99,532,800 kbps | 0x504331E3 | | ODU2e | 239/237 x 10,312,500 kbps | 0x4E9AF70A | | | | | | ODUflex for CBR | 239/238 x client signal | MAX LSP | | Client signals | bit rate | Bandwidth | | | | | | ODUflex for GFP-F | | MAX LSP | | Mapped client | Configured bit rate | Bandwidth | | signal | | | | | | | | ODUflex | Configured bit rate | MAX LSP | | resizable | | Bandwidth | +-------------------+-----------------------------+-----------------+

A single ISCD MAY be used for the advertisement of unbundled or bundled links supporting homogeneous multiplexing hierarchies and the same TS (tributary slot) granularity. A different ISCD MUST be used for each different muxing hierarchy (muxing tree in the following examples) and different TS granularity supported within the TE-Link.

When a received LSA includes a sub-TLV not formatted accordingly to the precise specifications in this document, the problem SHOULD be logged and the wrongly formatted sub-TLV MUST NOT be used for path computation.

Switching Capability Specific Information

The technology-specific part of the OTN-TDM ISCD may include a variable number of sub-TLVs called Bandwidth sub-TLVs. Each sub-TLV is encoded with the sub-TLV header as defined in RFC3630, Section 2.3.2. The muxing hierarchy tree MUST be encoded as an order-independent list. Two types of Bandwidth sub-TLVs are defined (TBA by IANA). Note that type values are defined in this document and not in RFC3630.

o Type 1 - Unreserved Bandwidth for fixed containers

o Type 2 - Unreserved/MAX LSP Bandwidth for flexible containers

The Switching Capability specific information (SCSI) MUST include one Type 1 sub-TLV for each fixed container and one Type 2 sub-TLV for each variable container. Each container type is identified by a Signal Type. Signal Type values are defined in RFC7139.

With respect to ODUflex, three different Signal Types are allowed:

o 20 - ODUflex(CBR) (i.e., 1.25*N Gbps)

o 21 - ODUflex(GFP-F), resizable (i.e., 1.25*N Gbps)

o 22 - ODUflex(GFP-F), non-resizable (i.e., 1.25*N Gbps)

where CBR stands for Constant Bit Rate, and GFP-F stands for Generic Framing Procedure - Framed.

Each MUST always be advertised in separate Type 2 sub-TLVs as each uses different adaptation functions [G.805]. In the case that both GFP-F resizable and non-resizable (i.e., 21 and 22) are supported, only Signal Type 21 SHALL be advertised as this type also implies support for Type 22 adaptation.

Switching Capability Specific Information for Fixed Containers

The format of the Bandwidth sub-TLV for fixed containers is depicted in the following figure:

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 (Unres-fix) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Signal Type | Num of stages |T|S| TSG | Res | Priority | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1 | ... | Stage#N | Padding | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unreserved ODUj at Prio 7 | Unreserved Padding | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

               Figure 3: Bandwidth Sub-TLV -- Type 1

The values of the fields shown in Figure 3 are explained in Section 4.1.3.

Switching Capability Specific Information for Variable

    Containers

The format of the Bandwidth sub-TLV for variable containers is depicted in the following figure:

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 (Unres/MAX-var) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Signal Type | Num of stages |T|S| TSG | Res | Priority | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1 | ... | Stage#N | Padding | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unreserved Bandwidth at priority 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unreserved Bandwidth at priority 7 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 7 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

               Figure 4: Bandwidth Sub-TLV -- Type 2

The values of the fields shown in figure 4 are explained in Section 4.1.3.

Switching Capability Specific Information -- Field Values and

    Explanation

The fields in the Bandwidth sub-TLV MUST be filled as follows:

o Signal Type (8 bits): Indicates the ODU type being advertised.

  Values are defined in RFC7139.

o Num of stages (8 bits): This field indicates the number of

  multiplexing stages used to transport the indicated Signal Type.
  It MUST be set to the number of stages represented in the sub-TLV.

o Flags (8 bits):

  *  T Flag (bit 17): Indicates whether the advertised bandwidth can
     be terminated.  When the Signal Type can be terminated T MUST
     be set, while when the Signal Type cannot be terminated T MUST
     be cleared.

  *  S Flag (bit 18): Indicates whether the advertised bandwidth can
     be switched.  When the Signal Type can be switched, S MUST be
     set; when the Signal Type cannot be switched, S MUST be
     cleared.

  *  The value 0 in both the T bit and S bit MUST NOT be used.

o TSG (3 bits): Tributary Slot Granularity. Used for the

  advertisement of the supported tributary slot granularity.  The
  following values MUST be used:

  *  0 - Ignored

  *  1 - 1.25 Gbps / 2.5 Gbps

  *  2 - 2.5 Gbps only

  *  3 - 1.25 Gbps only

  *  4-7 - Reserved

  A value of 1 MUST be used on interfaces that are configured to
  support the fallback procedures defined in [G.798].  A value of 2
  MUST be used on interfaces that only support 2.5 Gbps tributary
  slots, such as RFC4328 interfaces.  A value of 3 MUST be used on
  interfaces that are configured to only support 1.25 Gbps tributary
  slots.  A value of 0 MUST be used for non-multiplexed Signal Types
  (i.e., a non-OTN client).

o Res (3 bits): Reserved bits. MUST be set to 0 and ignored on

  receipt.

o Priority (8 bits): A bitmap used to indicate which priorities are

  being advertised.  The bitmap is in ascending order, with the
  leftmost bit representing priority level 0 (i.e., the highest) and
  the rightmost bit representing priority level 7 (i.e., the
  lowest).  A bit MUST be set (1) corresponding to each priority
  represented in the sub-TLV and MUST NOT be set (0) when the
  corresponding priority is not represented.  At least one priority
  level MUST be advertised that, unless overridden by local policy,
  SHALL be at priority level 0.

o Stage (8 bits): Each Stage field indicates a Signal Type in the

  multiplexing hierarchy used to transport the signal indicated in
  the Signal Type field.  The number of Stage fields included in a
  sub-TLV MUST equal the value of the Num of stages field.  The
  Stage fields MUST be ordered to match the data plane in ascending
  order (from the lowest order ODU to the highest order ODU).  The
  values of the Stage field are the same as those defined for the
  Signal Type field.  When the Num of stages field carries a 0, then
  the Stage and Padding fields MUST be omitted.

  *  Example: For the ODU1->ODU2->OD3 hierarchy, the Signal Type
     field is set to ODU1 and two Stage fields are present, the
     first indicating ODU2 and the second ODU3 (server layer).

o Padding (variable): The Padding field is used to ensure the 32-bit

  alignment of stage fields.  The length of the Padding field is
  always a multiple of 8 bits (1 byte).  Its length can be
  calculated, in bytes, as: 4 - ( "value of Num of stages field" %
  4).  The Padding field MUST be set to a zero (0) value on
  transmission and MUST be ignored on receipt.

o Unreserved ODUj (16 bits): This field indicates the Unreserved

  Bandwidth at a particular priority level.  This field MUST be set
  to the number of ODUs at the indicated the Signal Type for a
  particular priority level.  One field MUST be present for each bit
  set in the Priority field, and the fields are ordered to match the
  Priority field.  Fields MUST NOT be present for priority levels
  that are not indicated in the Priority field.

o Unreserved Padding (16 bits): The Padding field is used to ensure

  the 32-bit alignment of the Unreserved ODUj fields.  When present,
  the Unreserved Padding field is 16 bits (2 bytes) long.  When the
  number of priorities is odd, the Unreserved Padding field MUST be
  included.  When the number of priorities is even, the Unreserved
  Padding MUST be omitted.

o Unreserved Bandwidth (32 bits): This field indicates the

  Unreserved Bandwidth at a particular priority level.  This field
  MUST be set to the bandwidth, in bytes/second in IEEE floating
  point format, available at the indicated Signal Type for a
  particular priority level.  One field MUST be present for each bit
  set in the Priority field, and the fields are ordered to match the
  Priority field.  Fields MUST NOT be present for priority levels
  that are not indicated in the Priority field.

o Maximum LSP Bandwidth (32 bits): This field indicates the maximum

  bandwidth that can be allocated for a single LSP at a particular
  priority level.  This field MUST be set to the maximum bandwidth,
  in bytes/second in IEEE floating point format, available to a
  single LSP at the indicated Signal Type for a particular priority
  level.  One field MUST be present for each bit set in the Priority
  field, and the fields are ordered to match the Priority field.
  Fields MUST NOT be present for priority levels that are not
  indicated in the Priority field.  The advertisement of the MAX LSP
  Bandwidth MUST take into account HO OPUk bit rate tolerance and be
  calculated according to the following formula:

  *  Max LSP BW = (# available TSs) * (ODTUk.ts nominal bit rate) *
     (1-HO OPUk bit rate tolerance)

Examples

The examples in the following pages are not normative and are not intended to imply or mandate any specific implementation.

MAX LSP Bandwidth Fields in the ISCD

This example shows how the MAX LSP Bandwidth fields of the ISCD are filled according to the evolving of the TE-Link bandwidth occupancy. In this example, an OTU4 link is considered, with supported priorities 0,2,4,7 and muxing hierarchy ODU1->ODU2->ODU3->ODU4.

At time T0, with the link completely free, the advertisement would be:

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

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SwCap=OTN_TDM | Encoding = 12 | Reserved (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 0 = 100 Gbps | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 1 = 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 2 = 100 Gbps | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 3 = 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 4 = 100 Gbps | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 5 = 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 6 = 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 7 = 100 Gbps | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Switching Capability Specific Information | | (variable length) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

       Figure 5: MAX LSP Bandwidth Fields in the ISCD at T0

At time T1, an ODU3 at priority 2 is set up, so for priority 0, the MAX LSP Bandwidth is still equal to the ODU4 bandwidth, while for priorities from 2 to 7 (excluding the non-supported ones), the MAX LSP Bandwidth is equal to ODU3, as no more ODU4s are available and the next supported ODUj in the hierarchy is ODU3. The advertisement is updated 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

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SwCap=OTN_TDM | Encoding = 12 | Reserved (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 0 = 100 Gbps | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 1 = 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 2 = 40 Gbps | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 3 = 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 4 = 40 Gbps | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 5 = 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 6 = 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 7 = 40 Gbps | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Switching Capability Specific Information | | (variable length) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

       Figure 6: MAX LSP Bandwidth Fields in the ISCD at T1

At time T2, an ODU2 at priority 4 is set up. The first ODU3 has not been available since T1 as it was kept by the ODU3 LSP, while the second is no longer available and just 3 ODU2s are left in it. ODU2 is now the MAX LSP Bandwidth for priorities higher than 4. The advertisement is updated 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

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SwCap=OTN_TDM | Encoding = 12 | Reserved (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 0 = 100 Gbps | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 1 = 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 2 = 40 Gbps | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 3 = 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 4 = 10 Gbps | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 5 = 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 6 = 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 7 = 10 Gbps | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Switching Capability Specific Information | | (variable length) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

       Figure 7: MAX LSP Bandwidth Fields in the ISCD at T2

Example of T, S, and TS Granularity Utilization

In this example, an interface with tributary slot type 1.25 Gbps and fallback procedure enabled is considered (TS granularity=1). It supports the simple ODU1->ODU2->ODU3 hierarchy and priorities 0 and 3. Suppose that in this interface, the ODU3 Signal Type can be both switched or terminated, the ODU2 can only be terminated, and the ODU1 can only be switched. Please note that since the ODU1 is not being advertised to support ODU0, the value of its TSG field is "ignored" (TS granularity=0). For the advertisement of the capabilities of such an interface, a single ISCD is used. Its format is 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

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 (Unres-fix) | Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU1 | #stages= 2 |0|1| 0 |0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1=ODU2 | Stage#2=ODU3 | Padding (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU1 at Prio 0 | Unres ODU1 at Prio 3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 (Unres-fix) | Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU2 | #stages= 1 |1|0| 1 |0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1=ODU3 | Padding (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU2 at Prio 0 | Unres ODU2 at Prio 3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 (Unres-fix) | Length = 8 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU3 | #stages= 0 |1|1| 1 |0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU3 at Prio 0 | Unres ODU3 at Prio 3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

          Figure 8: T, S, and TS Granularity Utilization

Example of Different TS Granularities

In this example, two interfaces with homogeneous hierarchies but different tributary slot types are considered. The first one supports an RFC4328 interface (TS granularity=2) while the second one supports a G.709-2012 interface with fallback procedure disabled (TS granularity=3). Both support the ODU1->ODU2->ODU3 hierarchy and priorities 0 and 3. Suppose that in this interface, the ODU3 Signal Type can be both switched or terminated, the ODU2 can only be terminated, and the ODU1 can only be switched. For the advertisement of the capabilities of such interfaces, two different ISCDs are used. The format of their SCSIs is as follows:

SCSI of ISCD 1 -- TS granularity=2

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 (Unres-fix) | Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU1 | #stages= 2 |0|1| 0 |0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1=ODU2 | Stage#2=ODU3 | Padding (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU1 at Prio 0 | Unres ODU1 at Prio 3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 (Unres-fix) | Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU2 | #stages= 1 |1|0| 1 |0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1=ODU3 | Padding (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU2 at Prio 0 | Unres ODU2 at Prio 3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 (Unres-fix) | Length = 8 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU3 | #stages= 0 |1|1| 2 |0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU3 at Prio 0 | Unres ODU3 at Prio 3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Figure 9: Utilization of Different TS Granularities -- ISCD 1

SCSI of ISCD 2 -- TS granularity=3

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 (Unres-fix) | Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU1 | #stages= 2 |0|1| 0 |0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1=ODU2 | Stage#2=ODU3 | Padding (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU1 at Prio 0 | Unres ODU1 at Prio 3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 (Unres-fix) | Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU2 | #stages= 1 |1|0| 1 |0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1=ODU3 | Padding (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU2 at Prio 0 | Unres ODU2 at Prio 3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 (Unres-fix) | Length = 8 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU3 | #stages= 0 |1|1| 3 |0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU3 at Prio 0 | Unres ODU3 at Prio 3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

  Figure 10: Utilization of Different TS Granularities -- ISCD 2

Hierarchies with the same muxing tree but with different exported TS granularity MUST be considered as non-homogenous hierarchies. This is the case in which an H-LSP and the client LSP are terminated on the same egress node. What can happen is that a loose Explicit Route Object (ERO) is used at the hop where the signaled LSP is nested into the Hierarchical-LSP (H-LSP) (penultimate hop of the LSP).

In the following figure, node C receives a loose ERO from A; the ERO goes towards node E, and node C must choose between the ODU2 H-LSP on if1 or the one on if2. In this case, the H-LSP on if1 exports a TS=1.25 Gbps, and the H-LSP on if2 exports a TS=2.5 Gbps; because the service LSP being signaled needs a 1.25 Gbps tributary slot, only the H-LSP on if1 can be used to reach node E. For further details, please see Section 3.2 of RFC7096.

                      ODU0-LSP

     |                                                         |
     |                                     ODU2-H-LSP          |
     |                         +-------------------------------+
     |                         |                               |
  +--+--+      +-----+      +-----+ if1     +-----+         +-----+
  |     | OTU3 |     | OTU3 |     |---------|     |---------|     |
  |  A  +------+  B  +------+  C  | if2     |  D  |         |  E  |
  |     |      |     |      |     |---------|     |---------|     |
  +-----+      +-----+      +-----+         +-----+         +-----+

        ... Service LSP
        --- H-LSP

      Figure 11: Example of Service LSP and H-LSP Terminating
                         on the Same Node

Example of ODUflex Advertisement

In this example, the advertisement of an ODUflex->ODU3 hierarchy is shown. In the case of ODUflex advertisement, the MAX LSP Bandwidth needs to be advertised, and in some cases, information about the Unreserved Bandwidth could also be useful. The amount of Unreserved Bandwidth does not give a clear indication of how many ODUflex LSPs can be set up either at the MAX LSP Bandwidth or at different rates, as it gives no information about the spatial allocation of the free TSs.

An indication of the amount of Unreserved Bandwidth could be useful during the path computation process, as shown in the following example. Suppose there are two TE-Links (A and B) with MAX LSP Bandwidth equal to 10 Gbps each. In the case where 50 Gbps of Unreserved Bandwidth are available on Link A, 10 Gbps on Link B, and 3 ODUflex LSPs of 10 Gbps each have to be restored, for sure only one can be restored along Link B, and it is probable, but not certain, that two of them can be restored along Link A. The T, S, and TSG fields are not relevant to this example (filled with Xs).

In the case of ODUflex advertisement, the Type 2 Bandwidth sub-TLV is used.

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 (Unres/MAX-var) | Length = 72 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |S. type=ODUflex| #stages= 1 |X|X|X X X|0 0 0| Priority(8) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1=ODU3 | Padding (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unreserved Bandwidth at priority 0 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unreserved Bandwidth at priority 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unreserved Bandwidth at priority 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unreserved Bandwidth at priority 3 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unreserved Bandwidth at priority 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unreserved Bandwidth at priority 5 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unreserved Bandwidth at priority 6 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unreserved Bandwidth at priority 7 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                 Figure 12: ODUflex Advertisement

Example of Single-Stage Muxing

Suppose there is 1 OTU4 component link supporting single-stage muxing of ODU1, ODU2, ODU3, and ODUflex, the supported hierarchy can be summarized in a tree as in the following figure. For the sake of simplicity, we also assume that only priorities 0 and 3 are supported. The T, S, and TSG fields are not relevant to this example (filled with Xs).

      ODU1 ODU2  ODU3 ODUflex
         \   \    /   /
          \   \  /   /
           \   \/   /
              ODU4

The related SCSIs are 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

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 (Unres-fix) | Length = 8 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU4 | #stages= 0 |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU4 at Prio 0 =1 | Unres ODU4 at Prio 3 =1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 (Unres-fix) | Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU1 | #stages= 1 |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1=ODU4 | Padding (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU1 at Prio 0 =40 | Unres ODU1 at Prio 3 =40 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 (Unres-fix) | Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU2 | #stages= 1 |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1=ODU4 | Padding (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU2 at Prio 0 =10 | Unres ODU2 at Prio 3 =10 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 (Unres-fix) | Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU3 | #stages= 1 |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1=ODU4 | Padding (all zeros) |

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU3 at Prio 0 =2 | Unres ODU3 at Prio 3 =2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 2 (Unres/MAX-var) | Length = 24 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |S. type=ODUflex| #stages= 1 |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1=ODU4 | Padding (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unreserved Bandwidth at priority 0 =100 Gbps | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unreserved Bandwidth at priority 3 =100 Gbps | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 0 =100 Gbps | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 3 =100 Gbps | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                  Figure 13: Single-Stage Muxing

Example of Multi-Stage Muxing -- Unbundled Link

Suppose there is 1 OTU4 component link with muxing capabilities as shown in the following figure:

      ODU2 ODU0    ODUflex ODU0
         \ /            \ /
          |              |
        ODU3           ODU2
           \            /
            \          /
             \        /
              \      /
                ODU4

Considering only supported priorities 0 and 3, the advertisement is composed by the following Bandwidth sub-TLVs (T and S fields are not relevant to this example and filled with Xs):

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 (Unres-fix) | Length = 8 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU4 | #stages= 0 |X|X| 1 |0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU4 at Prio 0 =1 | Unres ODU4 at Prio 3 =1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 (Unres-fix) | Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU3 | #stages= 1 |X|X| 1 |0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1=ODU4 | Padding (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU3 at Prio 0 =2 | Unres ODU3 at Prio 3 =2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 (Unres-fix) | Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU2 | #stages= 1 |X|X| 1 |0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1=ODU4 | Padding (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU2 at Prio 0 =10 | Unres ODU2 at Prio 3 =10 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 (Unres-fix) | Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU2 | #stages= 2 |X|X| 0 |0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1=ODU3 | Stage#2=ODU4 | Padding (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU2 at Prio 0 =8 | Unres ODU2 at Prio 3 =8 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 (Unres-fix) | Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU0 | #stages= 2 |X|X| 0 |0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1=ODU3 | Stage#2=ODU4 | Padding (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU0 at Prio 0 =64 | Unres ODU0 at Prio 3 =64 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 (Unres-fix) | Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU0 | #stages= 2 |X|X| 0 |0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1=ODU2 | Stage#2=ODU4 | Padding (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU0 at Prio 0 =80 | Unres ODU0 at Prio 3 =80 |

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 2 (Unres/MAX-var) | Length = 24 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |S.type=ODUflex | #stages= 2 |X|X| 0 |0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1=ODU2 | Stage#2=ODU4 | Padding (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unreserved Bandwidth at priority 0 =100 Gbps | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unreserved Bandwidth at priority 3 =100 Gbps | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 0 =10 Gbps | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAX LSP Bandwidth at priority 3 =10 Gbps | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

          Figure 14: Multi-Stage Muxing -- Unbundled Link

Example of Multi-Stage Muxing -- Bundled Links

In this example, 2 OTU4 component links with the same supported TS granularity and homogeneous muxing hierarchies are considered. The following muxing capabilities trees are supported:

Component Link#1 Component Link#2

  ODU2 ODU0             ODU2 ODU0
     \ /                   \ /
      |                     |
     ODU3                  ODU3
      |                     |
     ODU4                  ODU4

Considering only supported priorities 0 and 3, the advertisement is as follows (the T, S, and TSG fields are not relevant to this example and filled with Xs):

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 (Unres-fix) | Length = 8 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU4 | #stages= 0 |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU4 at Prio 0 =2 | Unres ODU4 at Prio 3 =2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 (Unres-fix) | Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU3 | #stages= 1 |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1=ODU4 | Padding (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU3 at Prio 0 =4 | Unres ODU3 at Prio 3 =4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 (Unres-fix) | Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU2 | #stages= 2 |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1=ODU3 | Stage#2=ODU4 | Padding (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU2 at Prio 0 =16 | Unres ODU2 at Prio 3 =16 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 (Unres-fix) | Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU0 | #stages= 2 |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1=ODU3 | Stage#2=ODU4 | Padding (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU0 at Prio 0 =128 | Unres ODU0 at Prio 3 =128 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

          Figure 15: Multi-Stage Muxing -- Bundled Links

Example of Component Links with Non-Homogeneous Hierarchies

In this example, 2 OTU4 component links with the same supported TS granularity and non-homogeneous muxing hierarchies are considered. The following muxing capabilities trees are supported:

Component Link#1 Component Link#2

  ODU2 ODU0             ODU1 ODU0
     \ /                   \ /
      |                     |
     ODU3                  ODU2
      |                     |
     ODU4                  ODU4

Considering only supported priorities 0 and 3, the advertisement uses two different ISCDs, one for each hierarchy (the T, S, and TSG fields are not relevant to this example and filled with Xs). In the following figure, the SCSI of each ISCD is shown:

SCSI of ISCD 1 -- Component Link#1

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 (Unres-fix) | Length = 8 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU4 | #stages= 0 |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU4 at Prio 0 =1 | Unres ODU4 at Prio 3 =1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 (Unres-fix) | Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU3 | #stages= 1 |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1=ODU4 | Padding (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU3 at Prio 0 =2 | Unres ODU3 at Prio 3 =2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 (Unres-fix) | Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU2 | #stages= 2 |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1=ODU3 | Stage#2=ODU4 | Padding (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU2 at Prio 0 =8 | Unres ODU2 at Prio 3 =8 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 (Unres-fix) | Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU0 | #stages= 2 |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1=ODU3 | Stage#2=ODU4 | Padding (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU0 at Prio 0 =64 | Unres ODU0 at Prio 3 =64 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

  Figure 16: Multi-Stage Muxing -- Non-Homogeneous Hierarchies --
                              ISCD 1

SCSI of ISCD 2 -- Component Link#2

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 (Unres-fix) | Length = 8 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU4 | #stages= 0 |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU4 at Prio 0 =1 | Unres ODU4 at Prio 3 =1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 (Unres-fix) | Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU2 | #stages= 1 |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1=ODU4 | Padding (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU2 at Prio 0 =10 | Unres ODU2 at Prio 3 =10 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 (Unres-fix) | Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU1 | #stages= 2 |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1=ODU2 | Stage#2=ODU4 | Padding (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU1 at Prio 0 =40 | Unres ODU1 at Prio 3 =40 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 (Unres-fix) | Length = 12 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Sig type=ODU0 | #stages= 2 |X|X|X X X|0 0 0|1|0|0|1|0|0|0|0| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Stage#1=ODU2 | Stage#2=ODU4 | Padding (all zeros) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unres ODU0 at Prio 0 =80 | Unres ODU0 at Prio 3 =80 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

  Figure 17: Multi-Stage Muxing -- Non-Homogeneous Hierarchies --
                              ISCD 2

OSPFv2 Scalability

This document does not introduce OSPF scalability issues with respect to existing GMPLS encoding and does not require any modification to flooding frequency. Moreover, the design of the encoding has been carried out taking into account bandwidth optimization, in particular:

o Only unreserved and MAX LSP Bandwidth related to supported

  priorities are advertised.

o For fixed containers, only the number of available containers is

  advertised instead of the available bandwidth in order to use only
  16 bits per container instead of 32 (as per former GMPLS
  encoding).

In order to further reduce the amount of data advertised it is RECOMMENDED to bundle component links with homogeneous hierarchies as described in RFC4201 and illustrated in Section 5.6.

Compatibility

All implementations of this document MAY also support advertisement as defined in RFC4203. When nodes support both the advertisement method in RFC4203 and the one in this document, implementations MUST support the configuration of which advertisement method is followed. The choice of which is used is based on policy and beyond the scope of this document. This enables nodes following each method to identify similar supporting nodes and compute paths using only the appropriate nodes.

Security Considerations

This document extends RFC4203. As with RFC4203, it specifies the contents of Opaque LSAs in OSPFv2. As Opaque LSAs are not used for Shortest Path First (SPF) computation or normal routing, the extensions specified here have no direct effect on IP routing. Tampering with GMPLS TE LSAs may have an effect on the underlying transport (optical and/or Synchronous Optical Network - Synchronous Digital Hierarchy (SONET-SDH) network. RFC3630 notes that the security mechanisms described in RFC2328 apply to Opaque LSAs carried in OSPFv2. An analysis of the security of OSPF is provided in RFC6863 and applies to the extensions to OSPF as described in this document. Any new mechanisms developed to protect the transmission of information carried in Opaque LSAs will also automatically protect the extensions defined in this document.

Please refer to RFC5920 for details on security threats; defensive techniques; monitoring, detection, and reporting of security attacks; and requirements.

IANA Considerations

Switching Types

IANA has made the following assignment in the "Switching Types" section of the "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Parameters" registry located at <http://www.iana.org/assignments/gmpls-sig-parameters>:

Value Name Reference

---

-------------------------- ----------

110 OTN-TDM capable RFC7138

The same type of modification has been applied to the IANA-GMPLS-TC- MIB at <https://www.iana.org/assignments/ianagmplstc-mib>, where the value:

OTN-TDM (110), -- Time-Division-Multiplex OTN-TDM capable

has been added to the IANAGmplsSwitchingTypeTC ::= TEXTUAL-CONVENTION syntax list.

New Sub-TLVs

This document defines 2 new sub-TLVs that are carried in Interface Switching Capability Descriptors RFC4203 with the Signal Type OTN- TDM. Each sub-TLV includes a 16-bit type identifier (the T-field). The same T-field values are applicable to the new sub-TLV.

IANA has created and will maintain a new sub-registry, the "Types for sub-TLVs of OTN-TDM SCSI (Switching Capability Specific Information)" registry under the "Open Shortest Path First (OSPF) Traffic Engineering TLVs" registry, see <http://www.iana.org/assignments/ospf-traffic-eng-tlvs>, with the sub-TLV types as follows:

Value Sub-TLV Reference

---

-------------------------- ----------

0 Reserved RFC7138 1 Unreserved Bandwidth for RFC7138

           fixed containers

2 Unreserved/MAX Bandwidth for RFC7138

           flexible containers

3-65535 Unassigned

Types are to be assigned via Standards Action as defined in RFC5226.

10. Contributors

Diego Caviglia Ericsson Via E. Melen, 77 Genova Italy EMail: [email protected]

Dan Li Huawei Technologies Bantian, Longgang District Shenzhen 518129 P.R. China EMail: [email protected]

Pietro Vittorio Grandi Alcatel-Lucent Via Trento, 30 Vimercate Italy EMail: [email protected]

Khuzema Pithewan Infinera Corporation 140 Caspian CT. Sunnyvale, CA USA EMail: [email protected]

Xiaobing Zi Huawei Technologies EMail: [email protected]

Francesco Fondelli Ericsson EMail: [email protected]

Marco Corsi EMail: [email protected]

Eve Varma Alcatel-Lucent EMail: [email protected]

Jonathan Sadler Tellabs EMail: [email protected]

Lyndon Ong Ciena EMail: [email protected]

Ashok Kunjidhapatham EMail: [email protected]

Snigdho Bardalai EMail: [email protected]

Steve Balls EMail: [email protected]

Jonathan Hardwick EMail: [email protected]

Xihua Fu EMail: [email protected]

Cyril Margaria EMail: [email protected]

Malcolm Betts EMail: [email protected]

11. Acknowledgements

The authors would like to thank Fred Gruman and Lou Berger for their valuable comments and suggestions.

12. References

12.1. Normative References

[G.709-2012] ITU-T, "Interface for the optical transport network",

            Recommendation G.709/Y.1331, February 2012.

RFC2119 Bradner, S., "Key words for use in RFCs to Indicate

            Requirement Levels", BCP 14, RFC 2119, March 1997.

RFC3630 Katz, D., Kompella, K., and D. Yeung, "Traffic

            Engineering (TE) Extensions to OSPF Version 2", RFC
            3630, September 2003.

RFC4201 Kompella, K., Rekhter, Y., and L. Berger, "Link Bundling

            in MPLS Traffic Engineering (TE)", RFC 4201, October
            2005.

RFC4203 Kompella, K. and Y. Rekhter, "OSPF Extensions in Support

            of Generalized Multi-Protocol Label Switching (GMPLS)",
            RFC 4203, October 2005.

RFC4328 Papadimitriou, D., "Generalized Multi-Protocol Label

            Switching (GMPLS) Signaling Extensions for G.709 Optical
            Transport Networks Control", RFC 4328, January 2006.

12.2. Informative References

[G.798] ITU-T, "Characteristics of optical transport network

            hierarchy equipment functional blocks", Recommendation
            G.798, December 2012.

[G.805] ITU-T, "Generic functional architecture of transport

            networks", Recommendation G.805, March 2000.

RFC2328 Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.

RFC5226 Narten, T. and H. Alvestrand, "Guidelines for Writing an

            IANA Considerations Section in RFCs", BCP 26, RFC 5226,
            May 2008.

RFC5920 Fang, L., "Security Framework for MPLS and GMPLS

            Networks", RFC 5920, July 2010.

RFC6163 Lee, Y., Bernstein, G., and W. Imajuku, "Framework for

            GMPLS and Path Computation Element (PCE) Control of
            Wavelength Switched Optical Networks (WSONs)", RFC 6163,
            April 2011.

RFC6566 Lee, Y., Bernstein, G., Li, D., and G. Martinelli, "A

            Framework for the Control of Wavelength Switched Optical
            Networks (WSONs) with Impairments", RFC 6566, March
            2012.

RFC6863 Hartman, S. and D. Zhang, "Analysis of OSPF Security

            According to the Keying and Authentication for Routing
            Protocols (KARP) Design Guide", RFC 6863, March 2013.

RFC7062 Zhang, F., Li, D., Li, H., Belotti, S., and D.

            Ceccarelli, "Framework for GMPLS and PCE Control of
            G.709 Optical Transport Networks", RFC 7062, November
            2013.

RFC7096 Belotti, S., Grandi, P., Ceccarelli, D., Ed., Caviglia,

            D., and F. Zhang, "Evaluation of Existing GMPLS Encoding
            against G.709v3 Optical Transport Networks (OTNs)", RFC
            7096, January 2014.

RFC7139 Zhang, F., Ed., Zhang, G., Belotti, S., Ceccarelli, D.,

            and K.  Pithewan, "GMPLS Signaling Extensions for
            Control of Evolving G.709 Optical Transport Networks",
            RFC 7139, March 2014.

Authors' Addresses

Daniele Ceccarelli (editor) Ericsson Via E.Melen 77 Genova - Erzelli Italy

EMail: [email protected]

Fatai Zhang Huawei Technologies F3-5-B R&D Center, Huawei Base Bantian, Longgang District Shenzhen 518129 P.R. China

Phone: +86-755-28972912 EMail: [email protected]

Sergio Belotti Alcatel-Lucent Via Trento, 30 Vimercate Italy

EMail: [email protected]

Rajan Rao Infinera Corporation 140, Caspian CT. Sunnyvale, CA-94089 USA

EMail: [email protected]

John E. Drake Juniper

EMail: [email protected]