PCE Working Group | D. Dhody |
Internet-Draft | Y. Lee |
Intended status: Standards Track | Huawei Technologies |
Expires: April 27, 2015 | October 24, 2014 |
PCEP Extension for Transporting TE Data
draft-dhodylee-pce-pcep-te-data-extn-00
In order to compute and provide optimal paths, Path Computation Elements (PCEs) require an accurate and timely Traffic Engineering Database (TED). Traditionally this TED has been obtained from a link state routing protocol supporting traffic engineering extensions.
This document extends the Path Computation Element Communication Protocol (PCEP) with TED population capability.
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In Multiprotocol Label Switching (MPLS) and Generalized MPLS (GMPLS), a Traffic Engineering Database (TED) is used in computing paths for connection oriented packet services and for circuits. The TED contains all relevant information that a Path Computation Element (PCE) needs to perform its computations. It is important that the TED be complete and accurate each time, the PCE performs a path computation.
In MPLS and GMPLS, interior gateway routing protocols (IGPs) have been used to create and maintain a copy of the TED at each node running the IGP. One of the benefits of the PCE architecture [RFC4655] is the use of computationally more sophisticated path computation algorithms and the realization that these may need enhanced processing power not necessarily available at each node participating in an IGP.
Section 4.3 of [RFC4655] describes the potential load of the TED on a network node and proposes an architecture where the TED is maintained by the PCE rather than the network nodes. However, it does not describe how a PCE would obtain the information needed to populate its TED. PCE may construct its TED by participating in the IGP ([RFC3630] and [RFC5305] for MPLS-TE; [RFC4203] and [RFC5307] for GMPLS). An alternative is offered by BGP-LS [I-D.ietf-idr-ls-distribution] .
[I-D.lee-pce-transporting-te-data] proposes some other approaches for creating and maintaining the TED directly on a PCE as an alternative to IGPs and BGP flooding and investigate the impact from the PCE, routing protocol, and node perspectives.
[RFC5440] describes the specifications for the Path Computation Element Communication Protocol (PCEP). PCEP specifies the communication between a Path Computation Client (PCC) and a Path Computation Element (PCE), or between two PCEs based on the PCE architecture [RFC4655].
This document specifies a PCEP extension for TED population capability to support functionalities described in [I-D.lee-pce-transporting-te-data].
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].
The terminology is as per [RFC4655] and [RFC5440].
As per [I-D.lee-pce-transporting-te-data], the mechanism specified in this draft is applicable to:
A PCC may further choose to send only local TE information or both local and remote learned TED information.
How a PCE manages the TED information is implementation specific and thus out of scope of this document.
Following key requirements associated with TED population are identified for PCEP:
Several new functions are required in PCEP to support TED population. A function can be initiated either from a PCC towards a PCE (C-E) or from a PCE towards a PCC (E-C). The new functions are:
In this document, we define a new PCEP messages called TE Report (TERpt), a PCEP message sent by a PCC to a PCE to report TED. Each TE Report in a TERpt message can contain the TE node or TE Link properties. An unique PCEP specific TE identifier (TE-ID) is also carried in the message to identify the TE node or link and that remains constant for the lifetime of a PCEP session. This identifier on its own is sufficient when no IGP-TE or BGP-LS running in the network for PCE to learn TED. Incase PCE learns some information from PCEP and some from the existing mechanism, the PCC SHOULD include the mapping of IGP-TE or BGP-LS identifier to map the TED information populated via PCEP with IGP-TE/BGP-LS. See Section 8.1 for details.
During PCEP Initialization Phase, PCEP Speakers (PCE or PCC) advertise their support of TED population PCEP extensions. A PCEP Speaker includes the "TED Capability" TLV, described in Section 9, in the OPEN Object to advertise its support for PCEP TED extensions. The presence of the TED Capability TLV in PCC's OPEN Object indicates that the PCC is willing to send TE Reports whenever local TE information changes. The presence of the TED Capability TLV in PCE's OPEN message indicates that the PCE is interested in receiving TE Reports whenever local TE changes.
The PCEP protocol extensions for TED population MUST NOT be used if one or both PCEP Speakers have not included the TED Capability TLV in their respective OPEN message. If the PCE that supports the extensions of this draft but did not advertise this capability, then upon receipt of a PCRpt message from the PCC, it SHOULD generate a PCErr with error-type 19 (Invalid Operation), error-value TBD1 (Attempted TE Report if TED capability was not advertised) and it will terminate the PCEP session.
The TE reports sent by PCC MAY carry the remote TE information learned via existing means like IGP-TE and BGP-LS only if both PCEP Speakers set the R (remote) Flag in the "TED Capability" TLV to 'Remote Allowed (R Flag = 1)'. If this is not the case and TE reports carry remote TE information, then a PCErr with error-type 19 (Invalid Operation) and error-value TBD1 (Attempted TE Report if TED capability was not advertised) and it will terminate the PCEP session.
The purpose of TED Synchronization is to provide a checkpoint-in- time state replica of a PCC's TED in a PCE. State Synchronization is performed immediately after the Initialization phase (see [RFC5440]]). In case of stateful PCE ([I-D.ietf-pce-stateful-pce]) it is RECOMENDED that the TED synchronization should be done before LSP state synchronization.
During TED Synchronization, a PCC first takes a snapshot of the state of its TED, then sends the snapshot to a PCE in a sequence of TE Reports. Each TE Report sent during TE Synchronization has the SYNC Flag in the TE Object set to 1. The end of synchronization marker is a TERpt message with the SYNC Flag set to 0 for an TE Object with TED-ID equal to the reserved value 0. If the PCC has no TED state to synchronize, it will only send the end of synchronization marker.
Either the PCE or the PCC MAY terminate the session using the PCEP session termination procedures during the synchronization phase. If the session is terminated, the PCE MUST clean up state it received from this PCC. The session re-establishment MUST be re-attempted per the procedures defined in [RFC5440], including use of a back-off timer.
If the PCC encounters a problem which prevents it from completing the TED population, it MUST send a PCErr message with error-type TBD2 (TE Synchronization Error) and error-value 5 (indicating an internal PCC error) to the PCE and terminate the session.
The PCE does not send positive acknowledgements for properly received TED synchronization messages. It MUST respond with a PCErr message with error-type TBD2 (TE Synchronization Error) and error-value 1 (indicating an error in processing the TERpt) if it encounters a problem with the TE Report it received from the PCC and it MUST terminate the session.
The TE reports may carry local as well as remote TED information depending on the R flag in TED capability TLV.
The successful TED Synchronization sequences is shown in Figure 1.
+-+-+ +-+-+ |PCC| |PCE| +-+-+ +-+-+ | | |-----TERpt, SYNC=1----->| (Sync start) | | |-----TERpt, SYNC=1----->| | . | | . | | . | |-----TERpt, SYNC=1----->| | . | | . | | . | | | |-----TERpt, SYNC=0----->| (End of sync marker | | TE Report | | for TED-ID=0) | | (Sync done)
Figure 1: Successful state synchronization
The sequence where the PCE fails during the TED Synchronization phase is shown in Figure 2.
+-+-+ +-+-+ |PCC| |PCE| +-+-+ +-+-+ | | |-----TERpt, SYNC=1----->| | | |-----TERpt, SYNC=1----->| | . | | . | | . | |-----TERpt, SYNC=1----->| | | |-TERpt, SYNC=1 | | \ ,-PCErr---| | \ / | | \/ | | /\ | | / `-------->| (Ignored) |<--------` |
Figure 2: Failed TED synchronization (PCE failure)
The sequence where the PCC fails during the TED Synchronization phase is shown in Figure 3.
+-+-+ +-+-+ |PCC| |PCE| +-+-+ +-+-+ | | |-----TERpt, SYNC=1----->| | | |-----TERpt, SYNC=1----->| | . | | . | | . | |-------- PCErr--------->| | |
Figure 3: Failed TED synchronization (PCC failure)
TBD
The PCC MUST report any changes in the TEDB to the PCE by sending a TE Report carried on a TERpt message to the PCE, indicating that the TE state. Each TE node and TE Link would be uniquely identified by a PCEP TE identifier (TE-ID). The TE reports may carry local as well as remote TED information depending on the R flag in TED capability TLV. In case R flag is set, It MAY also include the mapping of IGP-TE or BGP-LS identifier to map the TED information populated via PCEP with IGP-TE/BGP-LS.
More details about TERpt message are in Section 8.1.
A permanent PCEP session MUST be established between a PCE and PCC supporting TED population via PCEP. In the case of session failure, session re-establishment MUST be re-attempted per the procedures defined in [RFC5440].
As defined in [RFC5440], a PCEP message consists of a common header followed by a variable-length body made of a set of objects that can be either mandatory or optional. An object is said to be mandatory in a PCEP message when the object must be included for the message to be considered valid. For each PCEP message type, a set of rules is defined that specify the set of objects that the message can carry. An implementation MUST form the PCEP messages using the object ordering specified in this document.
A PCEP TE Report message (also referred to as TERpt message) is a PCEP message sent by a PCC to a PCE to report the TED state. A TERpt message can carry more than one TE Reports. The Message-Type field of the PCEP common header for the PCRpt message is set to [TBD3].
The format of the PCRpt message is as follows:
<TERpt Message> ::= <Common Header> <te-report-list> Where: <te-report-list> ::= <TE>[<te-report-list>]
The TE object is a mandatory object which carries TE information of a TE node or a TE link. Each TE object has an unique TE-ID as described in Section 9.2. If the TE object is missing, the receiving PCE MUST send a PCErr message with Error-type=6 (Mandatory Object missing) and Error-value=[TBD4] (TE object missing).
A PCE may choose to implement a limit on the TE information a single PCC can populate. If a TERpt is received that causes the PCE to exceed this limit, it MUST send a PCErr message with error-type 19 (invalid operation) and error-value 4 (indicating resource limit exceeded) in response to the TERpt message triggering this condition and MAY terminate the session.
If a PCEP speaker has advertised the TED capability on the PCEP session, the PCErr message MAY include the TE object. If the error reported is the result of an TE report, then the TE-ID number MUST be the one from the TERpt that triggered the error.
The format of a PCErr message from [RFC5440] is extended as follows:
The format of the PCRpt message is as follows:
<PCErr Message> ::= <Common Header> ( <error-obj-list> [<Open>] ) | <error> [<error-list>] <error-obj-list>::=<PCEP-ERROR>[<error-obj-list>] <error>::=[<request-id-list> | <te-id-list>] <error-obj-list> <request-id-list>::=<RP>[<request-id-list>] <te-id-list>::=<TE>[<te-id-list>] <error-list>::=<error>[<error-list>]
The PCEP objects defined in this document are compliant with the PCEP object format defined in [RFC5440]. The P flag and the I flag of the PCEP objects defined in this document MUST always be set to 0 on transmission and MUST be ignored on receipt since these flags are exclusively related to path computation requests.
This document defines a new optional TLV for use in the OPEN Object.
The TED-CAPABILITY TLV is an optional TLV for use in the OPEN Object for TED population via PCEP capability advertisement. Its format is shown 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=[TBD5] | Length=4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flags |R| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The type of the TLV is [TBD5] and it has a fixed length of 4 octets.
The value comprises a single field - Flags (32 bits):
Unassigned bits are considered reserved. They MUST be set to 0 on transmission and MUST be ignored on receipt.
Advertisement of the TED capability implies support of local TE population, as well as the objects, TLVs and procedures defined in this document.
The TE (traffic engineering) object MUST be carried within TERpt messages and MAY be carried within PCErr messages. The TE object contains a set of fields used to specify the target TE node or link. It also contains a flag indicating to a PCE that the TED synchronization is in progress. The TLVs used with the TE object correlate with the IGP-TE/BGP-LS TE encodings.
TE Object-Class is [TBD6].
Two Object-Type values are defined for the TE object:
The format of the TE object body 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Protocol-ID | Flag |R|S| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TE-ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ // TLVs // | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Protocol-ID (8-bit): The field provide the source information. Incase PCC only provides local information (R flag is not set), it MUST use Protocol-ID as Direct. The following values are defined (same as [I-D.ietf-idr-ls-distribution]):
+-------------+----------------------------------+ | Protocol-ID | Source protocol | +-------------+----------------------------------+ | 1 | IS-IS Level 1 | | 2 | IS-IS Level 2 | | 3 | OSPFv2 | | 4 | Direct | | 5 | Static configuration | | 6 | OSPFv3 | +-------------+----------------------------------+
Flags (32-bit):
TE-ID(32-bit): A PCEP-specific identifier for the TE node or link. A PCC creates a unique TE-ID for each TE node/link that is constant for the lifetime of a PCEP session. The PCC will advertise the same TE-ID on all PCEP sessions it maintains at a given times. All subsequent PCEP messages then address the TE node/link by the TE-ID. The values of 0 and 0xFFFFFFFF are reserved.
Unassigned bits are considered reserved. They MUST be set to 0 on transmission and MUST be ignored on receipt.
TLVs that may be included in the TE Object are described in the following sections.
In case of remote TED population when existing IGP-TE/BGP-LS are also used, OSPF and IS-IS may run multiple routing protocol instances over the same link as described in [I-D.ietf-idr-ls-distribution]. See [RFC6822] and [RFC6549]. These instances define independent "routing universes". The 64-Bit 'Identifier' field is used to identify the "routing universe" where the TE object belongs. The TE objects representing IGP objects (nodes or links) from the same routing universe MUST have the same 'Identifier' value; TE objects with different 'Identifier' values MUST be considered to be from different routing universes.
The format of the ROUTING-UNIVERSE TLV is shown 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=[TBD7] | Length=8 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Identifier | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Below table lists the 'Identifier' values that are defined as well-known in this draft (same as [I-D.ietf-idr-ls-distribution]).
+------------+---------------------+ | Identifier | Routing Universe | +------------+---------------------+ | 0 | L3 packet topology | | 1 | L1 optical topology | +------------+---------------------+
If this TLV is not present the default value 0 is assumed.
As described in [I-D.ietf-idr-ls-distribution], each link is anchored by a pair of Router-IDs that are used by the underlying IGP, namely, 48 Bit ISO System-ID for IS-IS and 32 bit Router-ID for OSPFv2 and OSPFv3. Incase of additional auxiliary Router-IDs used for TE, these MUST also be included in the TE link attribute TLV (see Section 9.2.6).
It is desirable that the Router-ID assignments inside the TE Node Descriptor are globally unique. Autonomous System (AS) Number and PCEP-TED Identifier in order to disambiguate the Router-IDs, as described in [I-D.ietf-idr-ls-distribution].
The Local TE Node Descriptors TLV contains Node Descriptors for the node anchoring the local end of the link. This TLV MUST be included in the TE Report when during a given PCEP session a TE node/link is first reported to a PCE. A PCC sends to a PCE the first TE Report either during State Synchronization, or when a new TE node/link is learned at the PCC. The value contains one or more Node Descriptor Sub-TLVs, which allows specification of a flexible key for any given Node/Link information such that global uniqueness of the TE node/link is ensured.
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=[TBD8] | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | // Node Descriptor Sub-TLVs (variable) // | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The value contains one or more Node Descriptor Sub-TLVs defined in Section 9.2.4.
The Remote TE Node Descriptors contains Node Descriptors for the node anchoring the remote end of the link. This TLV MUST be included in the TE Report when during a given PCEP session a TE link is first reported to a PCE. A PCC sends to a PCE the first TE Report either during State Synchronization, or when a new TE link is learned at the PCC. The length of this TLV is variable. The value contains one or more Node Descriptor Sub-TLVs defined in Section 9.2.4.
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=[TBD9] | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | // Node Descriptor Sub-TLVs (variable) // | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Node Descriptor Sub-TLV type Type and lengths are listed in the following table:
+--------------------+-------------------+----------+ | Sub-TLV | Description | Length | +--------------------+-------------------+----------+ | TBD10 | Autonomous System | 4 | | TBD11 | BGP-LS Identifier | 4 | | TBD12 | OSPF Area-ID | 4 | | TBD13 | Router-ID | Variable | +--------------------+-------------------+----------+
The sub-TLV values in Node Descriptor TLVs are defined as follows (similar to [I-D.ietf-idr-ls-distribution]):
The TE Link Descriptors TLV contains Link Descriptors for each TE link. This TLV MUST be included in the TE Report when during a given PCEP session a TE link is first reported to a PCE. A PCC sends to a PCE the first TE Report either during State Synchronization, or when a new TE link is learned at the PCC. The length of this TLV is variable. The value contains one or more TE Link Descriptor Sub-TLVs
The 'TE Link descriptor' TLVs uniquely identify a link among multiple parallel links between a pair of anchor routers similar to [I-D.ietf-idr-ls-distribution].
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=[TBD14] | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | // Link Descriptor Sub-TLVs (variable) // | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Link Descriptor Sub-TLV type and lengths are listed in the following table:
+-----------+---------------------+---------------+-----------------+ | Sub-TLV | Description | IS-IS TLV | Value defined | | | | /Sub-TLV | in: | +-----------+---------------------+---------------+-----------------+ | TBD15 | Link Local/Remote | 22/4 | [RFC5307]/1.1 | | | Identifiers | | | | TBD16 | IPv4 interface | 22/6 | [RFC5305]/3.2 | | | address | | | | TBD17 | IPv4 neighbor | 22/8 | [RFC5305]/3.3 | | | address | | | | TBD18 | IPv6 interface | 22/12 | [RFC6119]/4.2 | | | address | | | | TBD19 | IPv6 neighbor | 22/13 | [RFC6119]/4.3 | | | address | | | +-----------+---------------------+---------------+-----------------+
The format and semantics of the 'value' fields in most 'Link Descriptor' sub-TLVs correspond to the format and semantics of value fields in IS-IS Extended IS Reachability sub-TLVs, defined in [RFC5305], [RFC5307] and [RFC6119]. Although the encodings for 'Link Descriptor' TLVs were originally defined for IS-IS, the TLVs can carry data sourced either by IS-IS or OSPF or direct.
The information about a link present in the LSA/LSP originated by the local node of the link determines the set of sub-TLVs in the Link Descriptor of the link as described in [I-D.ietf-idr-ls-distribution].
This is an optional, non-transitive attribute that is used to carry TE node attributes. The TE node attribute TLV may be encoded in the TE node Object.
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=[TBD20] | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | // Node Attributes Sub-TLVs (variable) // | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Node Attributes Sub-TLV type and lengths are listed in the following table:
+--------------+-----------------------+----------+-----------------+ | Sub TLV | Description | Length | Value defined | | | | | in: | +--------------+-----------------------+----------+-----------------+ | TBD21 | Node Flag Bits | 1 | [I-D.ietf-idr- | | | | | ls-distribution]| | | | | /3.3.1.1 | | TBD22 | Opaque Node | variable | [I-D.ietf-idr- | | | Properties | | ls-distribution]| | | | | /3.3.1.5 | | TBD23 | Node Name | variable | [I-D.ietf-idr- | | | | | ls-distribution]| | | | | /3.3.1.3 | | TBD24 | IS-IS Area Identifier | variable | [I-D.ietf-idr- | | | | | ls-distribution]| | | | | /3.3.1.2 | | TBD25 | IPv4 Router-ID of | 4 | [RFC5305]/4.3 | | | Local Node | | | | TBD26 | IPv6 Router-ID of | 16 | [RFC6119]/4.1 | | | Local Node | | | +--------------+-----------------------+----------+-----------------+
TE Link attribute TLV may be encoded in the TE Link Object. The format and semantics of the 'value' fields in some 'Link Attribute' sub-TLVs correspond to the format and semantics of value fields in IS-IS Extended IS Reachability sub-TLVs, defined in [RFC5305], [RFC5307] and [I-D.ietf-idr-ls-distribution]. Although the encodings for 'Link Attribute' TLVs were originally defined for IS-IS, the TLVs can carry data sourced either by IS-IS or OSPF or direct.
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=[TBD27] | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | // Link Attributes Sub-TLVs (variable) // | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The following 'Link Attribute' sub-TLVs are are valid :
+-----------+---------------------+--------------+------------------+ | Sub-TLV | Description | IS-IS TLV | Defined in: | | | | /Sub-TLV | | | | | BGP-LS TLV | | +-----------+---------------------+--------------+------------------+ | TBD28 | IPv4 Router-ID of | 134/--- | [RFC5305]/4.3 | | | Local Node | | | | TBD29 | IPv6 Router-ID of | 140/--- | [RFC6119]/4.1 | | | Local Node | | | | TBD30 | IPv4 Router-ID of | 134/--- | [RFC5305]/4.3 | | | Remote Node | | | | TBD31 | IPv6 Router-ID of | 140/--- | [RFC6119]/4.1 | | | Remote Node | | | | TBD32 | Link Local/Remote | 22/4 | [RFC5307]/1.1 | | | Identifiers | | | | TBD33 | Administrative | 22/3 | [RFC5305]/3.1 | | | group (color) | | | | TBD34 | Maximum link | 22/9 | [RFC5305]/3.3 | | | bandwidth | | | | TBD35 | Max. reservable | 22/10 | [RFC5305]/3.5 | | | link bandwidth | | | | TBD36 | Unreserved | 22/11 | [RFC5305]/3.6 | | | bandwidth | | | | TBD37 | TE Default Metric | 22/18 | [I-D.ietf-idr- | | | | | ls-distribution] | | | | | /3.3.2.3 | | TBD38 | Link Protection | 22/20 | [RFC5307]/1.2 | | | Type | | | | TBD39 | MPLS Protocol Mask | 1094 | [I-D.ietf-idr- | | | | | ls-distribution] | | | | | /3.3.2.2 | | TBD40 | IGP Metric | 1095 | [I-D.ietf-idr- | | | | | ls-distribution] | | | | | /3.3.2.4 | | TBD41 | Shared Risk Link | 1096 | [I-D.ietf-idr- | | | Group | | ls-distribution] | | | | | /3.3.2.5 | | TBD42 | Opaque link | 1097 | [I-D.ietf-idr- | | | attributes | | ls-distribution] | | | | | /3.3.2.6 | | TBD43 | Link Name attribute | 1098 | [I-D.ietf-idr- | | | | | ls-distribution] | | | | | /3.3.2.7 | +-----------+---------------------+--------------+------------------+
The main source of TE information is the IGP, which is not active on inter-AS links. In some cases, the IGP may have information of inter-AS links ([RFC5392], [RFC5316]). In other cases, an implementation SHOULD provide a means to inject inter-AS links into PCEP. The exact mechanism used to provision the inter-AS links is outside the scope of this document.
TBD.
TBD.
TBD.
TBD.
TBD.
TBD.
TBD.
This document borrows some of the structure and text from the [I-D.ietf-pce-stateful-pce].
[RFC2119] | Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. |
[RFC5440] | Vasseur, JP. and JL. Le Roux, "Path Computation Element (PCE) Communication Protocol (PCEP)", RFC 5440, March 2009. |
Udayasree Palle Huawei Technologies Leela Palace Bangalore, Karnataka 560008 India EMail: udayasree.palle@huawei.com