Network Working Group Dimitri Papadimitriou
Internet Draft Martin Vigoureux
Intended Status: Standards Track Alcatel-Lucent
Expiration Date: April 30, 2009 Kohei Shiomoto
NTT
Deborah Brungard
ATT
Jean-Louis Le Roux
France Telecom
October 31, 2008
Generalized Multi-Protocol Label Switching (GMPLS) Protocol
Extensions for Multi-Layer and Multi-Region Networks (MLN/MRN)
draft-ietf-ccamp-gmpls-mln-extensions-03.txt
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Copyright Notice
Copyright (C) The IETF Trust (2008).
Abstract
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There are requirements for the support of networks comprising LSRs
with different data plane switching layers controlled by a single
Generalized Multi Protocol Label Switching (GMPLS) control plane
instance, referred to as GMPLS Multi-Layer Networks/Multi-Region
Networks (MLN/MRN).
This document defines extensions to GMPLS routing and signaling
protocols so as to support the operation of GMPLS Multi-Layer/Multi-
Region Networks. It covers the elements of a single GMPLS control
plane instance controlling multiple LSP regions or layers within a
single TE domain.
Table of Content
1. Introduction................................................ 2
2. Summary of the Requirements and Evaluation.................. 3
3. Interface adaptation capability descriptor (IACD)........... 3
4. Multi-Region Signaling...................................... 6
5. Virtual TE link............................................. 8
6. Backward Compatibility...................................... 13
7. Security Considerations..................................... 13
8. IANA Considerations Sections................................ 13
9. References.................................................. 14
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 are to be interpreted as described in [RFC2119].
In addition the reader is assumed to be familiar with [RFC3945],
[RFC3471], [RFC4201], [RFC4202], [RFC4203], [RFC4205], and [RFC4206].
1. Introduction
Generalized Multi-Protocol Label Switching (GMPLS) [RFC3945]
extends MPLS to handle multiple switching technologies: packet
switching (PSC), layer-two switching (L2SC), TDM switching (TDM),
wavelength switching (LSC) and fiber switching (FSC). A GMPLS
switching type (PSC, TDM, etc.) describes the ability of a node to
forward data of a particular data plane technology, and uniquely
identifies a control plane region. LSP Regions are defined in
[RFC4206]. A network comprised of multiple switching types (e.g. PSC
and TDM) controlled by a single GMPLS control plane instance is
called a Multi-Region Network (MRN).
A data plane layer is a collection of network resources capable of
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terminating and/or switching data traffic of a particular format.
For example, LSC, TDM VC-11 and TDM VC-4-64c represent three
different layers. A network comprising transport nodes with
different data plane switching layers controlled by a single GMPLS
control plane instance is called a Multi-Layer Network (MLN).
The applicability of GMPLS to multiple switching technologies
provides the unified control and operations for both LSP provisioning
and recovery. This document covers the elements of a single GMPLS
control plane instance controlling multiple layers within a given TE
domain. A TE domain is defined as group of LSRs that enforces a
common TE policy. A CP instance can serve one, two or more layers.
Other possible approaches such as having multiple CP instances
serving disjoint sets of layers are outside the scope of this
document.
The next sections provide the procedural aspects in terms of routing
and signaling for such environments as well as the extensions
required to instrument GMPLS to provide the capabilities for MLM/MRN
unified control. The rationales and requirements for Multi-Layer/
Region networks are set forth in [MLN-REQ]. These requirements
are evaluated against GMPLS protocols in [MLN-EVAL] and several
areas where GMPLS protocol extensions are required are identified.
This document defines GMPLS routing and signaling extensions so as
to cover GMPLS MLN/MRN requirements.
2. Summary of the Requirements and Evaluation
As identified in [MLN-EVAL] most of MLN/MRN requirements rely on
mechanisms and procedures that are outside the scope of the GMPLS
protocols, and thus do not require any GMPLS protocol extensions.
They rely on local procedures and policies, and on specific TE
mechanisms and algorithms, which are outside the scope of GMPLS
protocols.
Four areas for extensions of GMPLS protocols and procedures have been
identified in [MLN-EVAL]:
o GMPLS routing extension for the advertisement of the internal
adjustment capability of hybrid nodes. See Section 3.2.2 of [MLN-
EVAL].
o GMPLS signaling extension for constrained multi-region signaling
(SC inclusion/exclusion). See Section 3.2.1 of [MLN-EVAL].
o GMPLS signaling extension for the setup/deletion of Virtual TE-
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links (as well as exact trigger for its actual provisioning). See
Section 3.1.1.2 of [MLN-EVAL].
o GMPLS routing and signaling extension for graceful TE-link
deletion (covered in [GR-TELINK]). See Section 3.1.1.3 of [MLN-
EVAL].
The first three requirements are addressed in Sections 3, 4 and 5,
respectively, of this document. The fourth requirement is addressed
in [GR-TELINK]. Companion documents address GMPLS OAM aspects that
have been identified in [MLN-EVAL].
3. Interface adaptation capability descriptor (IACD)
In the MRN context, nodes supporting more than one switching
capability on at least one interface are called Hybrid nodes. Hybrid
nodes contain at least two distinct switching elements that are
interconnected by "internal links" to provide adaptation between the
supported switching capabilities. These "internal links" have finite
capacities and must be taken into account when computing the path of
a multi-region TE-LSP.
The advertisement of the internal adaptation capability is required
as it provides critical information when performing multi-region path
computation.
3.1 Overview
In an MRN environment, some LSRs could contain, under the control of
a single GMPLS instance, multiple switching capabilities such as PSC
and TDM or PSC and Lambda Switching Capability (LSC).
These nodes, hosting multiple Interface Switching Capabilities (ISC),
just like other nodes (hosting a single Interface Switching
Capability) are required to hold and advertise resource information
on link states and topology. They also may have to consider certain
portions of internal node resources to terminate hierarchical label
switched paths (LSPs), since circuit switch capable units such as
TDMs, LSCs, and FSCs require rigid resources. For example, a node
with PSC+LSC hierarchical switching capability can switch a Lambda
LSP but may not be able to can never terminate the Lambda LSP if
there is no unused adaptation capability between the LSC and the PSC
switching capabilities.
Another example occurs when L2SC (Ethernet) switching can be adapted
in LAPS X.86 and GFP for instance before reaching the TDM switching
matrix. Similar circumstances can occur, if a switching fabric that
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supports both PSC and L2SC functionalities is assembled with LSC
interfaces enabling "lambda" encoding. In the switching fabric, some
interfaces can terminate Lambda LSPs and perform frame (or cell)
switching whilst other interfaces can terminate Lambda LSPs and
perform packet switching.
Therefore, within multi-region networks, the advertisement of the
so-called adaptation capability to terminate LSPs (not the interface
capability since the latter can be inferred from the bandwidth
available for each switching capability) provides critical
information to take into account when performing multi-region path
computation. This concept enables a node to discriminate the remote
nodes (and thus allows their selection during path computation) with
respect to their adaptation capability e.g. to terminate LSPs at the
PSC or LSC level.
Hence, we introduce the idea of discriminating the (internal)
adaptation capability from the (interface) switching capability by
considering an interface adaptation capability descriptor.
A more detailed problem statement can be found in [MLN-EVAL].
3.2 Interface Adjustment Capability Descriptor (IACD)
The interface adjustment capability descriptor (IACD) provides the
information for the forwarding/switching) capability only.
Note that the addition of the IACD as TE link attributes does not
modify format/messaging and processing associated to the Interface
Switching Capability Descriptor (ISCD) defined in [RFC4202].
3.2.1 OSPF
In OSPF, the IACD sub-TLV is defined as an optional sub-TLV of the TE
Link TLV (Type 2, see [RFC3630]), with Type 24 (to be assigned by
IANA) and variable length.
The IACD sub-TLV format is defined 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 | Switching Cap | Encoding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Max LSP Bandwidth at priority 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Max LSP Bandwidth at priority 1 |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Adjustment Capability-specific information |
| (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Switching Capability (SC) field (byte 1) - 8 bits
Indicates the lower switching capability (as defined for the
existing ISC sub-TLV) first Encoding field (byte 2): as defined
for the existing ISC sub-TLV.
Encoding (byte 2) - 8 bits
Contains one of the values specified in Section 3.1.1 of
[GMPLS-SIG] and updates.
Switching Capability (SC) field (byte 3) - 8 bits
Indicates the upper switching capability.
Encoding (byte 4) - 8 bits
Set to the encoding of the available adaptation pool and to
0xFF when the corresponding SC value has no access to the wire,
i.e., there is no ISC sub-TLV for this upper switching
capability.
Other fields MUST be processed as specified in [RFC4202] and
[RFC4203].
Multiple IACD sub-TLVs MAY be present within a given TE Link TLV
and the bandwidth simply provides an indication of resources still
available to perform insertion/ extraction for a given adjustment
(pool concept).
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The presence of the IACD sub-TLV as part of the TE Link TLV does not
modify format/messaging and processing associated to the ISCD defined
in [RFC4203].
3.2.2 IS-IS
In IS-IS, the IACD sub-TLV is an optional sub-TLV of the Extended IS
Reachability TLV (see [RFC3784]) with Type 24 (to be assigned by
IANA).
The IACD sub-TLV format is defined 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 | Switching Cap | Encoding |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Adjustment Capability-specific information |
| (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Where the fields have the same processing and interpretation rules as
for Section 3.2.1.
Multiple IACD sub-TLVs MAY be present within a given extended IS
reachability TLV and the bandwidth simply provides an indication of
resources still available to perform insertion/ extraction for a
given adjustment (pool concept).
The presence of the IACD sub-TLV as part of the extended IS
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reachability TLV does not modify format/messaging and processing
associated to the ISCD defined in [RFC4205].
4. Multi-Region Signaling
Section 6.2 of [RFC4206] specifies that when a region boundary node
receives a Path message, the node determines whether or not it is at
the edge of an LSP region with respect to the ERO carried in the
message. If the node is at the edge of a region, it must then
determine the other edge of the region with respect to the ERO,
using the IGP database. The node then extracts from the ERO the
subsequence of hops from itself to the other end of the region.
The node then compares the subsequence of hops with all existing FA-
LSPs originated by the node:
o If a match is found, that FA-LSP has enough unreserved bandwidth
for the LSP being signaled, and the PID of the FA-LSP is
compatible with the PID of the LSP being signaled, the node uses
that FA-LSP as follows. The Path message for the original LSP is
sent to the egress of the FA-LSP. The PHOP in the message is the
address of the node at the head-end of the FA-LSP. Before sending
the Path message, the ERO in that message is adjusted by removing
the subsequence of the ERO that lies in the FA-LSP, and replacing
it with just the end point of the FA-LSP.
o If no existing FA-LSP is found, the node sets up a new FA-LSP.
That is, it initiates a new LSP setup just for the FA-LSP.
Note: compatible PID implies that traffic can be processed by both
ends of the FA-LSP without drop.
Applying the procedure of [RFC4206], in a MRN environment MAY lead to
setup one-hop FA-LSPs between each node. Therefore, considering that
the path computation is able to take into account richness of
information with regard to the SC available on given nodes belonging
to the path, it is consistent to provide enough signaling information
to indicate the SC to be used and on over which link. Particularly,
in case a TE link has multiple SC advertised as part of its ISCD sub-
TLVs, an ERO does not allow selecting a particular SC.
Limiting modifications to existing RSVP-TE procedures [RFC3473] and
referenced, this document defines a new sub-object of the eXclude
Route Object (XRO), see [RFC4874], called Switching Capability sub-
object. This sub-object enables (when desired) the explicit
identification of (at least one) switching capability to be excluded
from the resource selection process described here above.
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Including this sub-object as part of the XRO that explicitly
indicates which SCs have to be excluded (before initiating the
procedure described here above) over a specified TE link solves the
ambiguous choice among SCs that are potentially used along a given
path and give the possibility to optimize resource usage on a multi-
region basis. Note that implicit SC inclusion is easily supported by
explicitly excluding other SCs (e.g. to include LSC, it is required
to exclude PSC, L2SC, TDM and FSC).
4.1 SC Subobject Encoding
The contents of an EXCLUDE_ROUTE object defined in [RFC4874] are a
series of variable-length data items called subobjects. This
document defines the Switching Capability (SC) subobject of the XRO
(Type 35), its encoding and processing.
Subobject Type TBD: Switching Capability
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L| Type | Length | Attribute | Switching Cap |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
L
0 indicates that the attribute specified MUST be excluded
1 indicates that the attribute specified SHOULD be avoided
Attribute
0 reserved value
1 indicates that the specified SC should be excluded or
avoided with respect to the preceding numbered (Type 1 or
Type 2) or unnumbered interface (Type) subobject
Switching Cap (8-bits)
Switching Capability value to be excluded.
This sub-object must follow the set of numbered or unnumbered
interface sub-objects to which this sub-object refers. In case, of
loose hop ERO subobject, the XRO sub-object must precede the loose-
hop sub-object identifying the tail-end node/interface of the
traversed region(s).
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Furthermore, it is expected, when label sub-object are following
numbered or unnumbered interface sub-objects, that the label value is
compliant with the SC capability to be explicitly excluded.
5. Virtual TE link
A virtual TE link is defined as a TE link between two upper layer
nodes that is not associated with a fully provisioned FA-LSP in a
lower layer. A virtual TE link is advertised as any TE link,
following the rules in [RFC4206] defined for fully provisioned TE
links. A virtual TE link represents thus the potentiality to setup an
FA-LSP in the lower layer to support the TE link that has been
advertised. In particular, the flooding scope of a virtual TE link is
within an IGP area, as is the case for any TE link.
Two techniques can be used for the setup, operation, and maintenance
of Virtual TE links. The corresponding GMPLS protocols extensions are
described in this section. The procedures described in this section
complement those defined in [RFC4206] and [HIER-BIS].
5.1 Edge-to-edge Association
This approach that does not require state maintenance on transit LSRs
relies on extensions to the GMPLS RSVP-TE Call procedure (see
[RFC4974]).
This technique consists of exchanging identification and TE
attributes information directly between TE link end points. These TE
link end-points correspond to the LSP head-end and tail-end points of
of the LSPs that will be established. The end-points MUST belong to
the same (LSP) region through the establishment of a call between
terminating LSRs.
Once the call is established the resulting association populates the
local TEDB and the resulting TE link is advertised as any other TE
link. The latter can then be used to attract traffic. Once an upper
layer/lower region LSP makes use of this TE link. A set of one or
more LSPs MUST be initially established using procedures defined in
[RFC4206] before the FA LSP can be used for nesting the incoming LSP.
In order to distinguish usage of such call from a classical call (as
defined e.g. in [RFC4139]), a CALL ATTRIBUTES object is introduced.
5.1.1 CALL_ATTRIBUTES Object
The CALL_ATTRIBUTES object is used to signal attributes required in
support of a call, or to indicate the nature or use of a call. It is
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built on the LSP-ATTRIBUTES object defined in [RFC4420].
The CALL_ATTRIBUTES object class is 201 (TBD by IANA) of the form
11bbbbbb. This C-Num value (see [RFC2205], Section 3.10) ensures that
LSRs that do not recognize the object pass it on transparently.
One C-Type is defined, C-Type = 1 for CALL Attributes. This object is
optional and may be placed on Notify messages to convey additional
information about the desired attributes of the call.
5.1.2 Processing
Specifically, if an egress (or intermediate) LSR does not support the
object, it forwards it unexamined and unchanged. This facilitates
the exchange of attributes across legacy networks that do not support
this new object.
The CALL_ATTRIBUTES object may be used to report call operational
state on a Notify message.
CALL_ATTRIBUTES class = 201, C-Type = 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// Attributes TLVs //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Attributes TLVs are encoded as described in Section 3.
5.1.3 Attributes TLVs
Attributes carried by the CALL_ATTRIBUTES object are encoded within
TLVs. One or more TLVs may be present in each object.
There are no ordering rules for TLVs, and no interpretation should be
placed on the order in which TLVs are received.
Each TLV is encoded 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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| |
// Value //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type
The identifier of the TLV.
Length
The total length of the TLV fields in bytes. If no Value field
is present the Length field contains the value four (4).
A Value field whose length is not a multiple of four MUST be
padded with a Reserved field so that the Length is a multiple
of four-octet. Thus, the Length MUST be at least 4, and MUST
be a multiple of 4.
Value
The data field for the TLV padded as described above.
5.1.4 Attributes Flags TLV
The TLV Type 1 indicates the Attributes Flags TLV. Other TLV types
may be defined in the future with type values assigned by IANA (see
Section 8). The Attributes Flags TLV may be present in a
CALL_ATTRIBUTES object.
The Attribute Flags TLV value field is an array of units of 32 flags
numbered from the most significant bit as bit zero. The Length field
for this TLV is therefore always a multiple of 4 bytes, regardless of
the number of bits carried and no padding is required.
Unassigned bits are considered as reserved and MUST be set to zero on
transmission by the originator of the object. Bits not contained in
the TLV MUST be assumed to be set to zero. If the TLV is absent
either because it is not contained in the CALL_ATTRIBUTES object or
because this object is itself absent, all processing MUST be
performed as though the bits were present and set to zero. That is to
say, assigned bits that are not present either because the TLV is
deliberately foreshortened or because the TLV is not included MUST be
treated as though they are present and are set to zero.
5.1.5 Call inheritance Flag
This document introduces a specific flag (MSB position bit 0) of the
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Attributes Flags TLV, to indicate that the association initiated
between the end-points belonging to a call results into a (virtual)
TE link advertisement.
The Call inheritance flag MUST be set to 1 in order to indicate that
the established association is to be translated into a TE link
advertisement. The value of this flag is by default set to 1. Setting
this flag to 0 results in a hidden TE link or in deleting the
corresponding TE link advertisement (by setting the corresponding
Opaque LSA Age to MaxAge).
The notify message used for establishing the association is defined
as per [RFC4974]. Additionally, the notify message must carry an
LSP_TUNNEL_INTERFACE_ID Object, that allows identifying unnumbered
FA-LSPs ([RFC3477], [RFC4206]) and numbered FA-LSPs ([RFC4206]).
5.2. Soft Forwarding Adjacency (Soft FA)
The Soft Forwarding Adjacency (Soft FA) approach consists of setting
up the FA LSP at the control plane level without actually committing
resources in the data plane. This means that the corresponding LSP
exists only in the control plane domain. Once such FA is established
the corresponding TE link can be advertised following the procedures
described in [RFC4206].
There are two techniques to setup Soft FAs:
o The first one consists in setting up the FA LSP by precluding
resource commitment during its establishment.
o The second technique consists in making use of path provisioned
LSPs only. In this case, there is no associated resource demand
during the LSP establishment. This can be considered as the RSVP-TE
equivalent of the Null service type specified in [RFC2997].
5.2.1 Pre-planned LSP Flag
The LSP ATTRIBUTES object and Attributes Flags TLV are defined in
[RFC4420]. The present document defines a new flag, the pre-planned
LSP Flag, in the existing Attributes Flags TLV (numbered as Type 1).
The position of this flag is TBD in accordance with IANA assignment.
This flag, part of the LSP_REQUIRED ATTRIBUTE object, follows
processing of [RFC4420] for that object. That is, LSRs that do not
recognize the object reject the LSP setup effectively saying that
they do not support the attributes requested. Indeed, the newly
defined attribute requires examination at all transit LSRs.
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The pre-planned LSP Flag can take one of the following values:
o When set to 0 this means that the LSP should be fully provisioned.
Absence of this flag (hence corresponding TLV) is therefore
compliant with the signaling message processing per [RFC3473])
o When set to 1 this means that the LSP should be provisioned in the
control plane only.
If an LSP is established with the pre-planned Flag set to 1, no
resources are committed at the data plane level.
The operation of committing data plane resources occurs by re-
signaling the same LSP with the pre-planned Flag set to 0. It is
RECOMMENDED that no other modifications are made to other RSVP
objects during this operation. That is each intermediate node,
processing a Flag transiting from 1 to 0 shall only be concerned with
the commitment of data plane resources and no other modification of
the LSP properties and/or attributes.
If an LSP is established with the pre-planned Flag set to 0, it MAY
be re-signaled by setting the Flag to 1.
5.2.2 Path Provisioned LSPs
There is a difference in between an LSP that is established with 0
bandwidth (path provisioning) and an LSP that is established with a
certain bandwidth value not committed at the data plane level (i.e.
pre-planned LSP).
However, the former is currently not possible using the GMPLS
protocol suite (following technology specific SENDER_TSPEC/FLOWSPEC
definition). Indeed, Traffic Parameters such as those defined in [RFC
4606] do not support setup of 0 bandwidth LSPs.
Mechanisms for provisioning (pre-planned or not) LSP with 0 bandwidth
is straightforward for PSC the SENDER_TSPEC/FLOWSPEC, the Peak Data
Rate field of Int-Serv objects, see [RFC2210], is set to 0. For L2SC
LSP, the CIR, EIR, CBS, and EBS must be set of 0 in the Type 2 sub-
TLV of the Ethernet Bandwidth Profile TLV. In these cases, upon LSP
resource commitment, actual traffic parameter values are used to
perform corresponding resource reservation.
For TDM and LSC LSP, a NULL Label value is used to prevent resource
allocation at the data plane level. In these cases, upon LSP resource
commitment, actual label value exchange is performed to commit
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allocation of timeslots/wavelengths.
6. Backward compatibility
New objects and procedures defined in this document are running
within a given TE domain. The latter, defined as group of LSRs that
enforces a common TE policy, is thus expected to run in the context
of a consistent TE policy. Specification for a consistent TE policy
is outside the scope of this document.
In such TE domains, we distinguish between edge LSRs and intermediate
LSRs. Edge LSRs must be able to process Call Attribute as defined in
Section 5.1 if this is method selected or creating edge-to-edge
associations. In that domain, intermediate LSRs are by definition
transparent to the Call processing.
In case the Soft FA method is used for the creation of Virtual TE
links, edge and intermediate LSRs must support processing of the LSP
ATTRIBUTE object per Section 5.2.
7. Security Considerations
This document does not introduce any new security consideration from
the ones already detailed in [MPLS-SEC] that describes the MPLS and
GMPLS security threats, the related defensive techniques, and the
mechanisms for detection and reporting. Indeed, the applicability of
the proposed GMPLS extensions is limited to single TE domain. Such
domain is under the authority of a single administrative entity. In
this context, multi-switching layer comprised within such TE domain
are under the control of a single GMPLS control plane instance.
Nevertheless, Call initiation, as depicted in section 5.1, MUST
strictly remain under control of the TE domain administrator. To
prevent any abuse of Call setup, edge nodes MUST ensure isolation of
their call controller (i.e. the latter is not reachable via external
TE domains). To further prevent man-in-the-middle attack, security
associations MUST be established between edge nodes initiating and
terminating calls. For this purpose, IKE [RFC4306] MUST be used for
performing mutual authentication and establishing and maintaining
these security associations.
8. IANA Considerations
8.1 RSVP
IANA has made the following assignments in the "Class Names, Class
Numbers, and Class Types" section of the "RSVP PARAMETERS" registry
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located at http://www.iana.org/assignments/rsvp-parameters.
This document introduces a new class named CALL_ATTRIBUTES has been
created in the 11bbbbbb range (201) with the following definition:
Class Number Class Name Reference
------------ ----------------------- ---------
201 CALL ATTRIBUTES [This I-D]
Class Type (C-Type):
1 Call Attributes [This.I-D]
This document introduces a new subobject for the EXCLUDE_ROUTE object
[RFC4874], C-Type 1.
Subobject Type Subobject Description
-------------- ---------------------
35 Switching Capability (SC)
8.2 OSPF
IANA maintains Open Shortest Path First (OSPF) Traffic Engineering
TLVs Registries included below for Top level Types in TE LSAs and
Types for sub-TLVs of TE Link TLV (Value 2).
This document defines the following sub-TLV of TE Link TLV (Value 2)
Value Sub-TLV
----- -------------------------------------------------
24 Interface Adjustment Capability Descriptor (IACD)
8.3 IS-IS
This document defines the following new sub-TLV type of top-level TLV
22 that need to be reflected in the ISIS sub-TLV registry for TLV 22:
Type Description Length
---- ------------------------------------------------- ------
24 Interface Adjustment Capability Descriptor (IACD) Variable
9. References
9.1 Normative References
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[GR-TELINK] Ali, Z., et al., "Graceful Shutdown in MPLS and
Generalized MPLS Traffic Engineering Networks", draft-
ietf-ccamp-mpls-graceful-shutdown, Work in progress.
[HIER-BIS] Shiomoto, K., and Farrel, A., "Procedures for Dynamically
Signaled Hierarchical Label Switched Paths", draft-ietf-
ccamp-lsp-hierarchy-bis, Work in progress.
[RFC2205] Braden, R., et al., "Resource ReSerVation Protocol
(RSVP) -- Version 1 Functional Specification",
RFC2205, September 1997.
[RFC2210] Wroclawski, J., "The Use of RSVP with IETF
Integrated Services", RFC2210, September 1997.
[RFC3471] Berger, L., et al., "Generalized Multi-Protocol Label
Switching (GMPLS) - Signaling Functional Description",
RFC3471, January 2003.
[RFC3473] Berger, L., "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Resource ReserVation
Protocol-Traffic Engineering (RSVP-TE) Extensions",
RFC3473, January 2003.
[RFC3630] Katz, D., et al., "Traffic Engineering (TE) Extensions to
OSPF Version 2," RFC3630, September 2003.
[RFC3784] Smit, H. and T. Li, "Intermediate System to
Intermediate System (IS-IS) Extensions for Traffic
Engineering (TE)", RFC3784, June 2004.
[RFC3945] Mannie, E. and al., "Generalized Multi-Protocol Label
Switching (GMPLS) Architecture", RFC3945, October 2004.
[RFC4201] Kompella, K., et al., "Link Bundling in MPLS Traffic
Engineering", RFC4201, October 2005.
[RFC4202] Kompella, K., Ed., and Rekhter, Y. Ed., "Routing
Extensions in Support of Generalized MPLS", RFC4202,
October 2005.
[RFC4203] Kompella, K., Ed., and Y. Rekhter, Ed., "OSPF Extensions
in Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC4203, October 2005.
[RFC4205] Kompella, K., Ed., and Y. Rekhter, Ed., "Intermediate
System to Intermediate System (IS-IS) Extensions in
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Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC4205, October 2005.
[RFC4206] Kompella, K., and Rekhter, Y., "LSP Hierarchy with
Generalized MPLS TE", RFC4206, October 2005.
[RFC4420] Farrel, A., et al., "Encoding of Attributes for
Multiprotocol Label Switching (MPLS) Label Switched Path
(LSP) Establishment Using Resource ReserVation Protocol-
Traffic Engineering (RSVP-TE)", RFC 4420, February 2006.
[RFC4428] Papadimitriou, D., et al. "Analysis of Generalized Multi-
Protocol Label Switching (GMPLS)-based Recovery
Mechanisms (including Protection and Restoration)",
RFC4428, March 2006.
[RFC4874] Lee, C.Y., et al. "Exclude Routes - Extension to RSVP-TE,"
RFC4874, April 2007.
[RFC4974] Papadimitriou, D., and Farrel, A., "Generalized MPLS
(GMPLS) RSVP-TE Signaling Extensions in support of Calls,"
RFC4974, August 2007.
9.2 Informative References
[MLN-EVAL] Leroux, J.-L., et al., "Evaluation of existing GMPLS
Protocols against Multi Region and Multi Layer Networks
(MRN/MLN)", RFC 5339, September 2008.
[MLN-REQ] Shiomoto, K., et al., "Requirements for GMPLS-based multi-
region and multi-layer networks (MRN/MLN)", RFC5212,
July 2008.
[MPLS-SEC] Fang, L. Ed., "Security Framework for MPLS and GMPLS
Networks", draft-ietf-mpls-mpls-and-gmpls-security-
framework-03.txt, Work in progress.
[MLRT] Imajuku, W., et al., "Multilayer routing using multilayer
switch capable LSRs", draft-imajuku-ml-routing-02.txt,
Work in Progress.
Acknowledgments
The authors would like to thank Mr. Wataru Imajuku for the
discussions on adaptation between regions [MLRT].
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Author's Addresses
Dimitri Papadimitriou
Alcatel-Lucent Bell
Copernicuslaan 50
B-2018 Antwerpen, Belgium
Phone: +32 3 2408491
E-mail: dimitri.papadimitriou@alcatel-lucent.be
Martin Vigoureux
Alcatel-Lucent
Route de Villejust
91620 Nozay, France
Tel : +33 1 30 77 26 69
Email: martin.vigoureux@alcatel-lucent.fr
Kohei Shiomoto
NTT
3-9-11 Midori-cho
Musashino-shi, Tokyo 180-8585, Japan
Phone: +81 422 59 4402
Email: shiomoto.kohei@lab.ntt.co.jp
Deborah Brungard
ATT
Rm. D1-3C22 - 200 S. Laurel Ave.
Middletown, NJ 07748, USA
Phone: +1 732 420 1573
Email: dbrungard@att.com
Jean-Louis Le Roux
France Telecom
Avenue Pierre Marzin
22300 Lannion, France
Phone: +33 (0)2 96 05 30 20
Email: jean-louis.leroux@rd.francetelecom.com
Contributors
Eiji Oki
NTT Network Service Systems Laboratories
3-9-11 Midori-cho
Musashino-shi, Tokyo 180-8585, Japan
Phone : +81 422 59 3441
Email: oki.eiji@lab.ntt.co.jp
Ichiro Inoue
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NTT Network Service Systems Laboratories
3-9-11 Midori-cho
Musashino-shi, Tokyo 180-8585, Japan
Phone : +81 422 59 6076
Email: ichiro.inoue@lab.ntt.co.jp
Emmanuel Dotaro
Alcatel-Lucent France
Route de Villejust
91620 Nozay, France
Phone : +33 1 6963 4723
Email: emmanuel.dotaro@alcatel-lucent.fr
Gert Grammel
Alcatel-Lucent SEL
Lorenzstrasse, 10
70435 Stuttgart, Germany
Email: gert.grammel@alcatel-lucent.de
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D. Papadimitriou Expires April 30, 2009 [Page 21]
