wdiff draft-ietf-mpls-generalized-cr-ldp-04.txt draft-ietf-mpls-generalized-cr-ldp-05.txt

Network Working Group Peter Ashwood-Smith (Nortel Networks Corp.)
Internet Draft Ayan Banerjee (Calient Networks)
Expiration Date: January May 2002 Lou Berger (Movaz Networks)
Greg Bernstein (Ciena Corporation)
John Drake (Calient Networks)
Yanhe Fan (Axiowave Networks)
Don Fedyk (Nortel Networks Corp.)
Kireeti Kompella (Juniper Networks, Inc.)
Eric Mannie (EBONE)
Jonathan P. Lang (Calient Networks)
Bala Rajagopalan (Tellium, Inc.)
Yakov Rekhter (Juniper Networks, Inc.)
Debanjan Saha (Tellium, Inc.)
Vishal Sharma (Jasmine Networks) (Metanoia, Inc.)
George Swallow (Cisco Systems)
Z. Bo Tang (Tellium, Inc.)

July

November 2001

Generalized MPLS Signaling - CR-LDP Extensions

draft-ietf-mpls-generalized-cr-ldp-04.txt

draft-ietf-mpls-generalized-cr-ldp-05.txt

Status of this Memo

This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026. Internet-Drafts are working
documents of the Internet Engineering Task Force (IETF), its areas,
and its working groups. Note that other groups may also distribute
working documents as Internet-Drafts.

Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."

To view the current status of any Internet-Draft, please check the
"1id-abstracts.txt" listing contained in an Internet-Drafts Shadow
Directory, see http://www.ietf.org/shadow.html.

Abstract

This document describes extensions to CR-LDP signaling required to
support Generalized MPLS. Generalized MPLS extends MPLS to encompass
time-division (e.g. SONET ADMs), wavelength (optical lambdas) and
spatial switching (e.g. incoming port or fiber to outgoing port or
fiber). This document presents a CR-LDP specific description of the
extensions. An RSVP-TE specific description can be found in [GMPLS-
RSVP]. A generic functional description is presented in [GMPLS-SIG].

Contents

1 Introduction .............................................. 3
2 Label Related Formats .................................... 3
2.1 Generalized Label Request ................................. 4
2.1.1 Procedures ................................................ 4
2.1.2 Bandwidth Encoding ........................................ 5
2.2 Generalized Label ......................................... 5
2.2.1 Procedures ................................................ 5
2.3 Waveband Switching ........................................ 6
2.3.1 Procedures ................................................ 6
2.4 Suggested Label ........................................... 7
2.5 Label Set ................................................. 7 8
2.5.1 Procedures ................................................ 8
3 Bidirectional LSPs ........................................ 9
3.1 Procedures ................................................ 9
4 Notification on Label Error ............................... 10
5 Explicit Label Control .................................... 10 11
5.1 Procedures ................................................ 11
6 Protection TLV ............................................ 12
6.1 Procedures ................................................ 12
7 Administrative Status Information ......................... 12 13
7.1 Admin Status Object ....................................... 12 TLV .......................................... 13
7.2 REQUEST and MAPPING Message Procedures .................... 13
7.3 Modification Message Procedures ........................... 13
7.3.1
7.2.1 Deletion procedure ........................................ 14
7.3.2 Compatibility ............................................. 14
7.3.3 Notify
7.3 Notification Message Procedures ................................. ........................... 14
7.3.1 Compatibility and Error Procedures ........................ 15
8 Control Channel Separation ................................ 15
8.1 Interface Identification .................................. 15
8.2 Procedures ................................................ 16
8.3 Errored Interface Identification .......................... 17
8.3.1 IF_ID Status TLVs ......................................... 17
8.3.2 Procedures ................................................ 18
9 Fault Handling ......................................... 16 18
10 Acknowledgments ........................................... 16 19
11 Security Considerations ................................... 17 19
12 IANA Considerations ....................................... 19
13 References ................................................ 17
13 20
14 Authors' Addresses ........................................ 17 20

[Editor's note: changes to be removed prior to publication as an RFC.]
Changes from previous version:

o Fixed Label Set format (for LDP)
o Removed unassigned values Revised Admin Status Usage
o Added Switching type of LSP being requested Clarified text related to interface bundling
(To be consistent with updated bundling draft.)
o Added Administrative Status Information (based on last call comments) IANA Considerations
o Added section on Control Channel Separation
(based on last call comments)
Covers:
- Separation of control Minor editorial changes and data channels clarifications

1. Introduction

Generalized MPLS extends MPLS from supporting packet (PSC) interfaces
and switching to include support of three new classes of interfaces
and switching: Time-Division Multiplex (TDM), Lambda Switch (LSC) and
Fiber-Switch (FSC). A functional description of the extensions to
MPLS signaling needed to support the new classes of interfaces and
switching is provided in [GMPLS-SIG]. This document presents CR-LDP
specific formats and mechanisms needed to support all four classes of
interfaces. RSVP-TE extensions can be found in [GMPLS-RSVP].

[GMPLS-SIG] should be viewed as a companion document to this
document. The format of this document parallels [GMPLS-SIG]. It
should be noted that the RSVP-TE specific version of Generalized MPLS
includes RSVP specific support for rapid failure notification, see
Section 4 [GMPLS-RSVP]. For CR-LDP there is not currently a similar
mechanism. When a failure is detected it will be propagated with
RELEASE/WITHDRAW messages radially outward from the point of failure.
Resources are to be released in this phase and actual resource
information may be fed back to the source using a feedback
mechanisms.

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].

2. Label Related Formats

This section defines formats for a generalized label request, a
generalized label, support for waveband switching, suggested label
and label sets.

2.1. Generalized Label Request

A REQUEST message SHOULD contain as specific an LSP Encoding Type as
possible to allow the maximum flexibility in switching by transit
LSRs. A Generalized Label Request TLV is set by the ingress node,
transparently passed by transit nodes, and used by the egress node.

The format of a Generalized Label Request is:

See [GMPLS-SIG] for a description of parameters.

2.1.1. Procedures

A node processing a REQUEST message containing a Generalized Label
Request must verify that the requested parameters can be satisfied by
the incoming interface, the node and by the outgoing interface. The
node may either directly support the LSP or it may use a tunnel (FA),
i.e., another class of switching. In either case, each parameter
must be checked.

Note that local node policy dictates when tunnels may be used and
when they may be created. Local policy may allow for tunnels to be
dynamically established or may be solely administratively controlled.
For more information on tunnels and processing of ER hops when using
tunnels see [MPLS-HIERARCHY].

Transit and egress nodes MUST verify that the node itself and, where
appropriate, that the outgoing interface or tunnel can support the
requested LSP Encoding Type. If encoding cannot be supported, the
node MUST generate a NOTIFICATION message, with a "Routing
problem/Unsupported Encoding" indication.

Nodes MUST verify that the type indicated in the Switching Type
parameter is supported on the corresponding incoming interface. If
the type cannot be supported, the node MUST generate a NOTIFICATION
message with a "Routing problem/Switching Type" indication.

The G-PID parameter is normally only examined at the egress. If the
indicated G-PID cannot be supported then the egress MUST generate a
NOTIFICATION message, with a "Routing problem/Unsupported GPID"
indication. In the case of PSC and when penultimate hop popping
(PHP) is requested, the penultimate hop also examines the (stored) G-
PID during the processing of the MAPPING message. In this case if
the G-PID is not supported, then the penultimate hop MUST generate a
NOTIFICATION message with a "Routing problem/Unacceptable label
value" indication. The generated NOTIFICATION message MAY include an
Acceptable Label Set, see Section 4.

When an error message is not generated, normal processing occurs. In
the transit case this will typically result in a REQUEST message
being propagated. In the egress case and PHP special case this will
typically result in a MAPPING message being generated.

2.1.2. Bandwidth Encoding

Bandwidth encodings are carried in the CR-LDP Traffic Parameters TLV.
See [GMPLS-SIG] for a definition of values to be used for specific
signal types. These values are set in the Peak and Committed Data
Rate fields of the Traffic Parameters TLV. Other bandwidth/service
related parameters in the TLV are ignored and carried transparently.

2.2. Generalized Label

The format of a Generalized Label is:

See [GMPLS-SIG] for a description of parameters and encoding of
labels.

2.2.1. Procedures

The Generalized Label travels in the upstream direction in MAPPING
messages.

The presence of both a generalized and normal label TLV in a MAPPING
message is a protocol error and should treated as a malformed message
by the recipient.

The recipient of a MAPPING message containing a Generalized Label
verifies that the values passed are acceptable. If the label is
unacceptable then the recipient MUST generate a NOTIFICATION message
with a "Routing problem/MPLS label allocation failure" indication.
The generated NOTIFICATION message MAY include an Acceptable Label
Set, see Section 4.

2.3. Waveband Switching

Waveband switching uses the same format as the generalized label, see
section 2.2. The type (0x0903) TBA is assigned for the Waveband Label.

In the context of waveband switching, the generalized label has the
following format:

0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| Type (TBA by IANA) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Waveband Id |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Start Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| End Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

See [GMPLS-SIG] for a description of parameters.

2.3.1. Procedures

The procedures defined in Section 2.2.1 apply to waveband switching.
This includes generating a NOTIFICATION message with a "Routing
problem/MPLS label allocation failure" indication if any of the label
fields are unrecognized or unacceptable.

Additionally, when a waveband is switched to another waveband, it is
possible that the wavelengths within the waveband will be mirrored
about a center frequency. When this type of switching is employed,
the start and end label in the waveband label TLV MUST be flipped
before forwarding the label TLV with the new waveband Id. In this
manner an egress/ingress LSR that receives a waveband label which has
these values inverted, knows that it must also invert its egress
association to pick up the proper wavelengths. Without this
mechanism and with an odd number of mirrored switching operations,
the egress LSRs will not know that an input wavelength of say L1 will
emerge from the waveband tunnel as L100.

This operation MUST be performed in both directions when a
bidirectional waveband tunnel is being established.

2.4. Suggested Label

The format of a suggested label is identical to a generalized label.
It is used in REQUEST messages. Suggested Label uses type = 0x904.

Errors in received Suggested Labels MUST be ignored. This includes
any received inconsistent or unacceptable values.

Per [GMPLS-SIG], if a downstream node passes a label value that
differs from the suggested label upstream, the upstream LSR MUST
either reconfigure itself so that it uses the label specified by the
downstream node or generate a NOTIFICATION message with a "Routing
problem/Unacceptable label value" indication. Furthermore, an
ingress node SHOULD NOT transmit data traffic using a suggested label
until the downstream node passes corresponding a label upstream.

2.5. Label Set

The format of a Label_Set Label Set is:

0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| type=0x0905 Type (TBA by IANA) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Action | Reserved | Label Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Subchannel 1 |
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
: : :
: : :
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Subchannel N |
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Label Type: 14 bits

Indicates the type and format of the labels carried in the TLV.
Values match the TLV type of the appropriate Label TLV.

See [GMPLS-SIG] for a description of other parameters.

2.5.1. Procedures

A Label Set is defined via one or more Label_Set Label Set TLVs. Specific
labels/subchannels can be added to or excluded from a Label Set via
Action zero (0) and one (1) TLVs respectively. Ranges of
labels/subchannels can be added to or excluded from a Label Set via
Action two (2) and three (3) TLVs respectively. When the Label_Set Label Set
TLVs only list labels/subchannels to exclude, this implies that all
other labels are acceptable.

The absence of any Label_Set Label Set TLVs implies that all labels are
acceptable. A Label Set is included when a node wishes to restrict
the label(s) that may be used downstream.

On reception of a REQUEST message, the receiving node will restrict
its choice of labels to one, which is in the Label Set. Nodes
capable of performing label conversion may also remove the Label Set
prior to forwarding the REQUEST message. If the node is unable to
pick a label from the Label Set or if there is a problem parsing the
Label_Set
Label Set TLVs, then the request is terminated and a NOTIFICATION
message with a "Routing problem/Label Set" indication MUST be
generated. It is a local matter if the Label Set is stored for later
selection on the MAPPING message or if the selection is made
immediately for propagation in the MAPPING. MAPPING message.

On reception of a REQUEST message, the Label Set represented in the
message is compared against the set of available labels at the
downstream interface and the resulting intersecting Label Set is
forwarded in a REQUEST message. When the resulting Label Set is
empty, the REQUEST must be terminated, and a NOTIFICATION message,
and a "Routing problem/Label Set" indication MUST be generated. Note
that intersection is based on the physical labels (actual
wavelength/band values) which may have different logical values on
different links, as a result it is the responsibility of the node to
map these values so that they have a consistent physical meaning, or
to drop the particular values from the set if no suitable logical
label value exists.

When processing a MAPPING message at an intermediate node, the label
propagated upstream MUST fall within the Label Set.

Note, on reception of a MAPPING message a node that is incapable of
performing label conversion has no other choice than to use the same
physical label (wavelength/band) as received in the MAPPING message.
In this case, the use and propagation of a Label Set will
significantly reduce the chances that this allocation will fail.

3. Bidirectional LSPs

Bidirectional LSP setup is indicated by the presence of an Upstream
Label in the REQUEST message. An Upstream Label has the same format
as the generalized label, see Section 2.2. Upstream Label uses
type=0x0906 type=
TBA

3.1. Procedures

The process of establishing a bidirectional LSP follows the
establishment of a unidirectional LSP with some additions. To
support bidirectional LSPs an Upstream Label is added to the REQUEST
message. The Upstream Label MUST indicate a label that is valid for
forwarding at the time the REQUEST message is sent.

When a REQUEST message containing an Upstream Label is received, the
receiver first verifies that the upstream label is acceptable. If
the label is not acceptable, the receiver MUST issue a NOTIFICATION
message with a "Routing problem/Unacceptable label value" indication.
The generated NOTIFICATION message MAY include an Acceptable Label
Set, see Section 4.

An intermediate node must also allocate a label on the outgoing
interface and establish internal data paths before filling in an
outgoing Upstream Label and propagating the REQUEST message. If an
intermediate node is unable to allocate a label or internal
resources, then it MUST issue a NOTIFICATION message with a "Routing
problem/Label allocation failure" indication.

Terminator nodes process REQUEST messages as usual, with the
exception that the upstream label can immediately be used to
transport data traffic associated with the LSP upstream towards the
initiator.

When a bidirectional LSP is removed, both upstream and downstream
labels are invalidated and it is no longer valid to send data using
the associated labels.

4. Notification on Label Error

This section defines the Acceptable_Label_Set Acceptable Label Set TLV to support
Notification on Label Error per [GMPLS-SIG]. An Acceptable_Label_Set Acceptable Label Set
TLV uses a type value of 0x0907. TBA The remaining contents of the TLV have
the identical format as the Label_Set Label Set TLV, see Section 2.5.

Acceptable_Label_Set

Acceptable Label Set TLVs may be carried in NOTIFICATION messages.
The procedures for defining an Acceptable Label Set follow the
procedures for defining a Label Set, see Section 2.5.1.
Specifically, an Acceptable Label Set is defined via one or more
Acceptable_Label_Set
Acceptable Label Set TLVs. Specific labels/subchannels can be added
to or excluded from an Acceptable Label Set via Action zero (0) and
one (1) TLVs respectively. Ranges of labels/subchannels can be added
to or excluded from an Acceptable Label Set via Action two (2) and
three (3) TLVs respectively. When the Acceptable_Label_Set Acceptable Label Set TLVs only
list labels/subchannels to exclude, this implies that all other
labels are acceptable.

The inclusion of Acceptable_Label_Set Acceptable Label Set TLVs is optional. If included,
the NOTIFICATION message SHOULD contain a "Routing
problem/Unacceptable label value" indication. The absence of
Acceptable_Label_Set
Acceptable Label Set TLVs does not have any specific meaning.

5. Explicit Label Control

The Label ER-Hop TLV 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0|0| Type (TBA by IANA) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L|U| Reserved | Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Label (continued) |
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

See [GMPLS-SIG] for a description of L, U and Label parameters.

5.1. Procedures

The Label ER-Hop follows a ER-Hop containing the IP address, or the
interface identifier [MPLS-UNNUM], associated with the link on which
it is to be used. The preceding ER-Hop must be strict. Up to two label ER-Hops may be present, one for
the downstream label and one for the upstream label. The following
SHOULD result in "Bad EXPLICIT_ROUTE" errors:
- If the first label ER-Hop is not preceded by a ER-Hop
containing an IP address, or a interface identifier
[MPLS-UNNUM], associated with an output link.
- For a label ER-Hop to follow a ER-Hop that has the L-bit
set
- On unidirectional LSP setup, for there to be a label ER-Hop
with the U-bit set
- For there to be two label ER-Hops with the same U-bit values

To support the label ER-Hop, a node must check to see if the ER-Hop
following its associate address/interface is a label ER-Hop. If it
is, one ER-Hop is examined for unidirectional LSPs and two ER-Hops
for bidirectional LSPs. If the U-bit of the ER-Hop being examined is
clear (0), then value of the label is copied into a new Label_Set Label Set
TLV. This Label_Set Label Set TLV MUST be included on the corresponding
outgoing MAPPING REQUEST message.

If the U-bit of the ER-Hop being examined is set (1), then value of
the label is label to be used for upstream traffic associated with
the bidirectional LSP. If this label is not acceptable, a "Bad
EXPLICIT_ROUTE" error SHOULD be generated. If the label is
acceptable, the label is copied into a new Upstream Label TLV. This
Upstream Label TLV MUST be included on the corresponding outgoing
MAPPING
REQUEST message.

After processing, the label ER-Hops are removed from the ER.

Note an implication of the above procedures is that the label ER-Hop
should never be the first ER-Hop in a newly received message. If the
label ER-Hop is the first ER-Hop an a received ER, then it SHOULD be
treated as a "Bad strict node" error.

Procedures by which an LSR at the head-end of an LSP obtains the
information needed to construct the Label ER-Hop are outside the
scope of this document.

6. Protection TLV

The use of the Protection TLV is optional. The TLV is included to
indicate specific protection attributes of an LSP.

The format of Protection Information TLV is:

See [GMPLS-SIG] for a description of parameters.

6.1. Procedures

Transit nodes processing a REQUEST message containing a Protection
TLV MUST verify that the requested protection can be satisfied by the
outgoing interface or tunnel (FA). If it cannot, the node MUST
generate a NOTIFICATION message, with a "Routing problem/Unsupported
Link Protection" indication.

7. Administrative Status Information

Administrative Status Information is carried in the Admin Status TLV.
The TLV provides information related to the administrative state of a
particular LSP. The information is used in two ways. In the first,
the object TLV is carried in REQUEST and MAPPING messages to indicate the
administrative state of an LSP. In the second, the TLV is carried in
a REQUEST and MAPPING
Notification message with the modification bit set to request a change to the administrative state
of an LSP.

7.1. Admin Status Object TLV

The use of the Admin Status TLV is optional. It uses Type = TBA. The
format of the TLV is:

The format of Admin Status TLV in REQUEST, MAPPING and Notification
Messages is:

The U Bit Should be set to 1. The F bit should be set to 1.

See [GMPLS-SIG] for a description of parameters.

7.2. REQUEST and MAPPING Message Procedures

The Admin Status TLV is used to notify each node along the path of
the status of the LSP. Status information is processed by each Each node processes status information based
on local policy and then propagated in the corresponding outgoing
messages. The TLV is inserted in REQUEST messages at the discretion
of the ingress node. The absence of the TLV is the equivalent to
receiving a TLV containing values all set to zero.

Transit nodes receiving a REQUEST message containing an Admin Status
TLV, update their local state, take any appropriate local action
based on the indicated status and then propagate the received Admin
Status TLV in the outgoing REQUEST message.

Egress

Edge nodes receiving a REQUEST message containing an Admin Status
TLV, also update their local state and take any appropriate local
action based on the indicated status.

The subsequent MAPPING message MUST carry back When the Admin ADMIN Status TLV
if the corresponding request message had the Admin Status TLV.

7.3. Modification Message Procedures

Subsequent messaging Admin Status messaging is all performed by
REQUEST and MAPPING Messages using
received with the modification action indicator
flag. The ingress may begin R bit set, the propagation of receiving edge node should reflect
the received values in a Message with corresponding MAPPING message.
Specifically, if an
Admin Status TLV. Each subsequent egress node propagates the REQUEST receives a Request message with the Admin Status TLV from the ingress to R
bit of the egress Admin_Status TLV set and then the
egress node returns the MAPPING messages back Upstream carrying the
Admin Status TLV. A modification node SHOULD send a
Mapping message containing an Admin_Status TLV with the same values
set, with the exception of this type would
typically only carry the mandatory CR-LDP TLVs and R bit, as received in the Admin Status
TLV.

7.3.1.
corresponding Request message.

7.2.1. Deletion procedure

In some circumstances, particularly optical networks, it is useful to
set the administrative status of an LSP before tearing it down.

In such circumstances the procedure SHOULD be followed when deleting
an
LSP: LSP from the ingress: The ingress node precedes an LSP deletion by
inserting an Admin Status TLV in a REQUEST Notification Message with the modification action
indicator set to modify message and setting the Down
Reflect (R) and Delete (D) bit. bits. Transit and egress nodes process the Admin
Status TLV as described
above. by passing the Notification message. The egress node May
respond with a Notification message with the Admin Status TLV. Upon
receiving the Admin Status TLV with the Down Delete (D) bit set in the
MAPPING message with the modification action indicator set to modify
Notification message, the ingress node sends egress SHOULD respond with a RELEASE LABEL WITHDRAW
message downstream to remove the LSP and normal CR-LDP processing takes place.

7.3.2. Compatibility

It is possible that some nodes along an LSP will not support the
Admin Status TLV.

In such circumstances the case of procedure SHOULD be followed when deleting
an LSP from the egress: The egress node indicates its desire for
deletion by inserting an Admin Status TLV in a non-supporting transit node, Notification message
and setting Delete (D) bit. Transit nodes process the Admin Status
TLV will pass through as described above. Upon receiving the Admin Status TLV with the
Delete (D) bit set in the Notification message, the ingress node unmodified
sends a LABEL RELEASE message downstream to remove the LSP and normal
CR-LDP processing can
continue. In takes place.

7.3. Notification Message Procedures

Subsequent messaging Admin Status messaging may be performed by
Notification Messages. The ingress may begin the case propagation of a non-supporting egress node,
Notification Message with an Admin Status TLV. Each subsequent node
propagates the Notification with the Admin Status TLV may not be reflected back in the MAPPING Message. In this
case, from the
ingress SHOULD continue to set the contents of egress and then the egress node returns the
Notification messages back Upstream carrying the object
normally but, when processing an LSP deletion, it MUST NOT wait for
an updated Admin Status TLV in a MAPPING message before issuing a
RELEASE/WITHDRAW message.

7.3.3. Notify Message Procedures TLV.

Intermediate and egress nodes may trigger the setting of
administrative status before a deletion via the use of REQUEST Notification messages. To
accomplish this, an intermediate or egress node generates a REQUEST
Notification message with the modification action indicator
set to modify and with the corresponding upstream. upstream notify session
information. The Admin Status TLV MUST be included in the message, session
information, with the Down (D) appropriate bit or bits set. The Reflect (R)
bit MUST NOT be set.

An ingress or egress node receiving a MAPPING Notification message containing
an Admin Status TLV with the Down Delete (D) bit set, SHOULD initiate the
deletion procedure described in the previous section.

8. Control Channel Separation

This section provides the protocol specific formats

7.3.1. Compatibility and procedures to Error Procedures

Some special processing is required support a control channel not being in-band with a data
channel.

8.1. Interface Identification

The choice of the data interface in order to use is always made by the sender
of cover the REQUEST message. The choice case of
nodes that do not support the data interface is indicated
by Admin Status TLV and other error
conditions. Specifically, a node that sends a Notification message
containing an Admin Status TLV with the Down (D) bit set MUST verify
that it receives a corresponding LABEL RELEASE message within a
configurable period of time. By default this period of time SHOULD
be 30 seconds. If the node does not receive such a LABEL RELEASE
message, it SHOULD send a Label Release message downstream and a
LABEL WITHDRAW message upstream.

8. Control Channel Separation

This section provides the protocol specific formats and procedures to
required support a control channel not being in-band with a data
channel.

8.1. Interface Identification

The choice of the data interface to use is always made by the sender
of the REQUEST message. The choice of the data interface is indicated
by the sender of the REQUEST message by including the data channel's
interface identifier in the message using a new Interface TLV. type.
For bidirectional LSPs, the sender chooses the data interface in each
direction. In all cases but bundling [MPLS-BUNDLE] the upstream
interface is implied by the downstream interface. For bundling, the
path
REQUEST sender explicitly identifies the component interface used in
each direction.

The format of Interface ID in REQUEST, MAPPING Messages IPV4 Interface ID in REQUEST, MAPPING Messages is:

0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| Type (TBA by IANA) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Next/Previous Hop Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Logical Interface ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface ID TLVS see [GMLPS-SIG] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The format of IPV6 Interface ID TLV in REQUEST, MAPPING Messages is:

0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| Type (TBA by IANA) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 Next/Previous Hop Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Logical Interface ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface ID TLVS see [GMLPS-SIG] |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

See [GMPLS-SIG] for a description of parameters.

See [CR-LDP] for a description of signaling address. See [GMPLS-SIG]
for a description of parameters and encoding of TLVs.

8.2. Procedures

An IF_ID TLV is used on links where there is not a one-to- one
association of a control channel to a data channel, see [GMPLS- SIG].

The LDP session uses the IF_ID TLV to identify the data channel(s)
associated with the LSP. For a unidirectional LSP, a downstream data
channel MUST be indicated. For bidirectional LSPs, a common
downstream and upstream data channel is normally indicated. In the
special case where a bidirectional LSP that traverses a bundled link,
it is possible to specify a downstream data channel that differs from
the upstream data channel. Data channels are specified from the view
point of the sender of the Path message. The IF_ID TLV SHOULD NOT be
used when no TLVs are needed.

A node receiving one or more IF_ID TLVs in a REQUEST message saves
their values and returns them in the subsequent MAPPING message sent
to the node that originated the TLVs.

As with [MPLS-TE], the node originating an IF_ID TLV must ensure that
the selected outgoing interface is consistent with the outgoing ER
TLV. A node that receives an IF_ID TLV SHOULD check whether the
information carried in this TLV is consistent with the information
carried in a received ER TLV, and if not it MUST send a LABEL ABORT
Message with the status code of "Bad Explicit Routing TLV Error"
toward the sender.

8.3. Errored Interface Identification

There are cases where it is useful to indicate a specific interface
associated with an error. To support these cases the IF_ID Status
TLV are defined.

8.3.1. IF_ID Status TLVs

The format of the IPv4 IF_ID Status TLV is:

0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| Type (TBA by IANA) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Next/Previous Hop Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Status Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ TLVs ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The format of the IPv6 IF_ID Status TLV is:

0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| Type (TBA by IANA) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Interface ID TLVS see [GMLPS-SIG] |
| IPv6 Error Node Address |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Status Code |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ TLVs ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

The U Bit Should be set to 0. The F bit should be set to 0.

See [GMPLS-SIG] for a description of parameters.

See [CR-LDP] [RFC3036] for a description of signaling address. status code value fields.
See [GMPLS-SIG] for a description of parameters and encoding of
TLVs.

8.2.

8.3.2. Procedures

An IF_ID TLV is used on links where there

Nodes wishing to indicate that an error is not a one-to- one
association of a control channel related to a data channel, see [GMPLS- SIG].

The LDP session uses specific
interface SHOULD use the appropriate IF_ID Status TLV to identify the data channel(s)
associated with the LSP. For a unidirectional LSP, a forward channel
MUST be indicated. For a bidirectional LSP that use bundled links, a
reverse channel MUST be indicated. Data channels are specified from
the viewpoint of the sender of in the REQUEST
corresponding LABEL WITHDRAW or LABEL RELEASE message. IF_ID Status
TLV SHOULD be generated and processed as any other Status TLV, see
[RFC3036].

9. Fault Handling

In optical transport networks, failures in the out-of-fiber signaling
communication or optical control plane should not have service impact
on the existing optical connections. Under such circumstances, a
mechanism MUST exist to detect a signaling communication failure and
a recovery procedure SHALL guarantee connection integrity at both
ends of the signaling channel.

The LDP Fault tolerant draft [LDP-FT] specifies the procedures for
recovering LDP and CR-LDP sessions under failure. Please refer to
this his
draft for procedures on recovering optical connections. Currently
the Fault tolerant draft covers many of the common failure modes for
a separated control and data plane.

10. Acknowledgments

This draft is the work of numerous authors and consists of a
composition of a number of previous drafts in this area. A list of
the drafts from which material and ideas were incorporated follows:

draft-saha-rsvp-optical-signaling-00.txt
draft-lang-mpls-rsvp-oxc-00.txt
draft-kompella-mpls-optical-00.txt
draft-fan-mpls-lambda-signaling-00.txt

Valuable comments and input were received from a number of people,
notably Adrian Farrel.

11. Security Considerations

This draft introduce no new security considerations to [CR-LDP].

12. IANA Considerations

This draft uses the LDP [RFC 3031] name spaces, which require
assignment for the following TLVs.

o Generalized Label Request (TLV TBA)
o Generalized Label (TLV TBA)
o Upstream Label (TLV TBA)
o Label Set (TLV TBA)
o Waveband Label (TLV TBA)
o ER-Hop (TLV TBA)
o Acceptable Label Set (TLV TBA)
o Admin Status (TLV TBA)
o Interface ID (TLV TBA)
o IPV4 Interface ID (TLV TBA)
o IPV6 Interface ID (TLV TBA)
o IPv4 IF_ID Status (TLV TBA)
o IPv6 IF_ID Status (TLV TBA)

13. References

[CR-LDP] Jamoussi et al., "Constraint-Based LSP Setup using LDP",
Internet Draft, draft-ietf-mpls-cr-ldp-05.txt, Feb., Jul., 2001.

[RFC3036] Andersson et al., "LDP Specification",
RFC 3036.

[MPLS-HIERARCHY] Kompella, K., and Rekhter, Y., "LSP Hierarchy with
MPLS TE", Internet Draft,
draft-ietf-mpls-lsp-hierarchy-02.txt, Feb., Sep., 2001.

[MPLS-UNNUM] Kompella, K., Rekhter, Y., Kullberg, A., "Signalling
Unnumbered Links in CR-LDP", Internet Draft,
draft-ietf-mpls-crldp-unnum-01.txt, February
draft-ietf-mpls-crldp-unnum-02.txt, Sep. 2001

[GMPLS-RSVP] Ashwood-Smith, P. et al, "Generalized MPLS Signaling -
RSVP-TE Extensions", Internet Draft,
draft-ietf-mpls-generalized-rsvp-te-01.txt,
February
draft-ietf-mpls-generalized-rsvp-te-06.txt,
November 2001.

[GMPLS-SIG] Ashwood-Smith, P. et al, "Generalized MPLS -
Signaling Functional Description", Internet Draft,
draft-ietf-mpls-generalized-signaling-02.txt,
February
draft-ietf-mpls-generalized-signaling-07.txt,
November 2001.

[LDP-FT] Farrel, A. et al, "Fault Tolerance for LDP
and CR-LDP", Internet Draft,
draft-ietf-mpls-ldp-ft-02.txt,
February
May 2001.

[MPLS-BUNDLE] Kompella, K., Rekhter, Y., and Berger, L., "Link Bundling
in MPLS Traffic Engineering", Internet Draft,
draft-kompella-mpls-bundle-05.txt, Sep., 2001.

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels," RFC 2119.

13.

14. Authors' Addresses

Peter Ashwood-Smith
Nortel Networks Corp.
P.O. Box 3511 Station C,
Ottawa, ON K1Y 4H7
Canada
Phone: +1 613 763 4534
Email: petera@nortelnetworks.com
Ayan Banerjee
Calient Networks
5853 Rue Ferrari
San Jose, CA 95138
Phone: +1 408 972-3645
Email: abanerjee@calient.net

Lou Berger
Movaz Networks, Inc.
7926 Jones Branch Drive
Suite 615
McLean VA, 22102
Phone: +1 703 847-1801
Email: lberger@movaz.com

Greg Bernstein
Ciena Corporation
10480 Ridgeview Court
Cupertino, CA 94014
Phone: +1 408 366 4713
Email: greg@ciena.com

John Drake
Calient Networks
5853 Rue Ferrari
San Jose, CA 95138
Phone: +1 408 972 3720
Email: jdrake@calient.net

Yanhe Fan
Axiowave Networks, Inc.
100
200 Nickerson Road
Marlborough, MA 01752
Phone: +1 508 460 6969 Ext. 627 + 1 774 348 4627
Email: yfan@axiowave.com

Don Fedyk
Nortel Networks Corp.
600 Technology Park
Billerica MA 01821
Phone: +1 978 288 3041
Fax: +1 978 288 0620
Email: dwfedyk@nortelnetworks.com
Kireeti Kompella
Juniper Networks, Inc.
1194 N. Mathilda Ave.
Sunnyvale, CA 94089
Email: kireeti@juniper.net

Jonathan P. Lang
Calient Networks
25 Castilian
Goleta, CA 93117
Email: jplang@calient.net

Eric Mannie
EBONE
Terhulpsesteenweg 6A
1560 Hoeilaart - Belgium
Phone: +32 2 658 56 52
Mobile: +32 496 58 56 52
Fax: +32 2 658 51 18
Email: eric.mannie@ebone.com

Bala Rajagopalan
Tellium, Inc.
2 Crescent Place
P.O. Box 901
Oceanport, NJ 07757-0901
Phone: +1 732 923 4237
Fax: +1 732 923 9804
Email: braja@tellium.com

Yakov Rekhter
Juniper Networks, Inc.
Email: yakov@juniper.net

Debanjan Saha
Tellium Optical Systems
2 Crescent Place
Oceanport, NJ 07757-0901
Phone: +1 732 923 4264
Fax: +1 732 923 9804
Email: dsaha@tellium.com
Vishal Sharma
Jasmine Networks,
Metanoia, Inc.
3061 Zanker Road, Suite B
335 Elan Village Lane, Unit 203
San Jose, CA 95134 95134-2539
Phone: +1 408 895 5030
Fax: +1 408 895 5050 408-943-1794
Email: vsharma@jasminenetworks.com v.sharma@ieee.org

George Swallow
Cisco Systems, Inc.
250 Apollo Drive
Chelmsford, MA 01824
Voice: +1 978 244 8143
Email: swallow@cisco.com

Z. Bo Tang
Tellium, Inc.
2 Crescent Place
P.O. Box 901
Oceanport, NJ 07757-0901
Phone: +1 732 923 4231
Fax: +1 732 923 9804
Email: btang@tellium.com

Generated on: Fri Jul 20 16:49:49 EDT Wed Nov 21 15:23:23 EST 2001