MPLS Working Group E. Bellagamba, Ed.
Internet-Draft L. Andersson
Intended status: Standards Track Ericsson
Expires: September 11, 2011 P. Skoldstrom, Ed.
Acreo AB
D. Ward
J. Drake
Juniper
March 10, 2011
Configuration of pro-active MPLS-TP Operations, Administration, and
Maintenance (OAM) Functions Using LSP Ping
draft-ietf-mpls-lsp-ping-mpls-tp-oam-conf-01
Abstract
This specification describes the configuration of pro-active MPLS-TP
Operations, Administration, and Maintenance (OAM) Functions for a
given LSP using a set of TLVs that is carried on LSP Ping.
Status of this Memo
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to this document. Code Components extracted from this document must
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
1.2. Overview of BFD OAM operation . . . . . . . . . . . . . . 4
2. Overview of MPLS OAM for Transport Applications . . . . . . . 4
3. Theory of Operations . . . . . . . . . . . . . . . . . . . . . 5
3.1. MPLS OAM Configuration Operation Overview . . . . . . . . 5
3.2. OAM Functions TLV . . . . . . . . . . . . . . . . . . . . 7
3.2.1. BFD Configuration sub-TLV . . . . . . . . . . . . . . 8
3.2.1.1. Local Discriminator sub-TLV . . . . . . . . . . . 10
3.2.1.2. Negotiation Timer Parameters sub-TLV . . . . . . . 10
3.2.1.3. MPLS OAM SOURCE MEP-ID sub-TLV . . . . . . . . . . 12
3.2.1.4. BFD Authentication sub-TLV . . . . . . . . . . . . 12
3.2.2. MPLS OAM PM Loss sub-TLV . . . . . . . . . . . . . . . 13
3.2.3. MPLS OAM PM Delay sub-TLV . . . . . . . . . . . . . . 14
3.2.4. MPLS OAM FMS sub-TLV . . . . . . . . . . . . . . . . . 15
3.3. IANA Considerations . . . . . . . . . . . . . . . . . . . 16
4. OAM configuration errors . . . . . . . . . . . . . . . . . . . 16
5. Security Considerations . . . . . . . . . . . . . . . . . . . 17
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17
6.1. Normative References . . . . . . . . . . . . . . . . . . . 17
6.2. Informative References . . . . . . . . . . . . . . . . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19
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1. Introduction
This document describes the configuration of pro-active MPLS-TP
Operations, Administration, and Maintenance (OAM) Functions for a
given LSP using TLVs carried in LSP Ping [BFD-Ping]. In particular
it specifies the mechanisms necessary to establish MPLS-TP OAM
entities monitoring an LSP and defines information elements and
procedures to configure pro-active MPLS OAM functions.
Initialization and control of on-demand MPLS OAM functions are
expected to be carried out by directly accessing network nodes via a
management interface; hence configuration and control of on-demand
OAM functions are out-of-scope for this document.
Because the Transport Profile of MPLS, by definition [RFC5654], must
be capable of operating without a control plane, there are two
options for in-band OAM: by using an NMS or by using LSP Ping if a
control plane is not instantiated.
Pro-active MPLS OAM is based on the Bidirectional Forwarding
Detection (BFD) protocol [RFC5880]. Bidirectional Forwarding
Detection (BFD), as described in [RFC5880], defines a protocol that
provides low- overhead, short-duration detection of failures in the
path between two forwarding engines, including the interfaces, data
link(s), and to the extent possible the forwarding engines
themselves. BFD can be used to track the liveliness and detect data
plane failures of MPLS-TP point-to-point and might also be extended
to p2mp connections.
MPLS Transport Profile (MPLS-TP) describes a profile of MPLS that
enables operational models typical in transport networks, while
providing additional OAM, survivability and other maintenance
functions not currently supported by MPLS. [RFC5860] defines the
requirements for the OAM functionality of MPLS-TP.
BFD has been chosen to be the basis of pro-active MPLS-TP OAM
functions. MPLS-TP OAM extensions for transport applications, for
which this document specifies the configuration, are specified in
[BFD-CCCV], [MPLS-PM], and [MPLS-FMS].
1.1. Requirements Language
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 RFC 2119 [RFC2119].
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1.2. Overview of BFD OAM operation
BFD is a simple hello protocol that in many respects is similar to
the detection components of well-known routing protocols. A pair of
systems transmits BFD packets periodically over each path between the
two systems, and if a system stops receiving BFD packets for long
enough, some component in that particular bidirectional path to the
neighboring system is assumed to have failed. Systems may also
negotiate to not send periodic BFD packets in order to reduce
overhead.
A path is only declared to be operational when two-way communication
has been established between systems, though this does not preclude
the use of unidirectional links to support bidirectional paths (co-
routed or bidirectional or associated bidirectional).
Each system estimates how quickly it can send and receive BFD packets
in order to come to an agreement with its neighbor about how rapidly
detection of failure will take place. These estimates can be
modified in real time in order to adapt to unusual situations. This
design also allows for fast systems on a shared medium with a slow
system to be able to more rapidly detect failures between the fast
systems while allowing the slow system to participate to the best of
its ability. However, in some cases one may want to configure these
timers manually, in those cases the TLVs defined in this document can
be used.
The ability of each system to control the BFD packet transmission
rate in both directions provides a mechanism for congestion control,
particularly when BFD is used across multiple network hops.
As recommended in [BFD-CCCV], the BFD tool needs to be extended for
the proactive CV functionality by the addition of an unique
identifier in order to meet the requirements. The document in [BFD-
CCCV] specifies the BFD extension and behavior to meet the
requirements for MPLS-TP proactive Continuity Check and Connectivity
Verification functionality and the RDI functionality as defined in
[RFC5860].
2. Overview of MPLS OAM for Transport Applications
[MPLS-TP-OAM-FWK] describes how MPLS OAM mechanisms are operated to
meet transport requirements outlined in [RFC5860].
[BFD-CCCV] specifies two BFD operation modes: 1) "CC mode", which
uses periodic BFD message exchanges with symmetric timer settings,
supporting Continuity Check, 2) "CV/CC mode" which sends unique
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maintenance entity identifiers in the periodic BFD messages
supporting Connectivity Verification as well as Continuity Check.
[MPLS-PM] specifies mechanisms for performance monitoring of LSPs, in
particular it specifies loss and delay measurement OAM functions.
[MPLS-FMS] specifies fault management signals with which a server LSP
can notify client LSPs about various fault conditions to suppress
alarms or to be used as triggers for actions in the client LSPs. The
following signals are defined: Alarm Indication Signal (AIS), Link
Down Indication (LDI) and Locked Report (LKR). To indicate client
faults associated with the attachment circuits Client Signal Failure
Indication (CSF) can be used. CSF is described in [MPLS-TP-OAM-FWK]
and in the context of this document is for further study.
[MPLS-TP-OAM-FWK] describes the mapping of fault conditions to
consequent actions. Some of these mappings may be configured by the
operator, depending on the application of the LSP. The following
defects are identified: Loss Of Continuity (LOC), Misconnectivity,
MEP Misconfiguration and Period Misconfiguration. Out of these
defect conditions, the following consequent actions may be
configurable: 1) whether or not the LOC defect should result in
blocking the outgoing data traffic; 2) whether or not the "Period
Misconfiguration defect" should result a signal fail condition.
3. Theory of Operations
3.1. MPLS OAM Configuration Operation Overview
LSP Ping, or alternatively RSVP-TE [RSVP-TE CONF], can be used to
simply establish (i.e., bootstrap) a BFD session or it can
selectively enable and configure all pro-active MPLS OAM functions.
For this specification, BFD MUST be run in asynchronous mode and both
sides should be in active mode.
In the simplest scenario LSP Ping, or alternatively RSVP-TE [RSVP-TE
CONF], is used only to bootstrap the BFD session. In this case the
initiating node includes an "OAM Functions TLV" in the LSP Echo
Request message it sends to the receiving node at the other end of
the LSP. This TLV includes a number of flags that are used to
indicate what types of OAM should be enabled as well as sub-TLVs
containing the parameters to be used with corresponding OAM
functions. In this simple case it has the CC OAM Functions flag is
set, and a "BFD Configuration sub-TLV" is included. The sub-TLV
carries a "Local Discriminator sub-TLV" with the discriminator value
selected by the initiating node for the BFD session associated with
the LSP. The N flag in the "BFD Configuration sub-TLV" MUST be set
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to enable timer negotiation/re-negotiation via BFD Control Messages.
The receiving node MUST use the Local Discriminator value it receives
to identify the remote end of the BFD session. The receiving node
must send a LSP Echo Response message to the initiating node that
includes an "OAM Functions TLV" containing the same values as it
received, except for the "Local Discriminator sub-TLV", which
contains the local discriminator value selected by the receiving node
for the BFD session.
Timer negotiation is performed in subsequent BFD control messages.
This operation is similar to LSP Ping based bootstrapping described
in [RFC5884].
If timer negotiation is to be done using the TLVs defined in this
document rather than with BFD Control packets, the N flag of the "BFD
Configuration sub-TLV" MUST be cleared and a "Timer Negotiation
Parameters sub-TLV" MUST be present in the "BFD Configuration sub-
TLV". In this case, there are two configuration options, symmetric
and asymmetric. If symmetric configuration is used, the S flag in
"BFD Configuration sub-TLV" MUST be set. If the flag is cleared, the
configuration is completed asymmetrically in the two directions.
Section 3.3.1 includes a detailed explanation of such configuration.
In the case of the "CV/CC mode" OAM [BFD-CCCV], the "CV" flag MUST be
set in addition to the CC flag in the "BFD Configuration sub-TLV".
The information required to support this functionality is defined in
[MPLS-TP-IDENTIF]. If the "CV" flag is set the "BFD Configuration
sub-TLV" MUST include a "MPLS OAM SOURCE MEP-ID sub-TLV" containing
these parameters.
When BFD Control packets are transported in the G-ACh they are not
protected by any end-to-end checksum, only lower-layers are providing
error detection/correction. A single bit error, e.g. a flipped bit
in the BFD State field could cause the receiving end to wrongly
conclude that the link is down and thus trigger protection switching.
To prevent this from happening the "BFD Configuration sub-TLV" has an
Integrity flag that when set enables BFD Authentication using Keyed
SHA1 with an empty key (all 0s) [RFC5880]. This would make every BFD
Control packet carry an SHA1 hash of itself that can be used to
detect errors.
If BFD Authentication using a shared key / password is desired (i.e.
actual authentication not only error detection) the "BFD
Authentication sub-TLV" MUST be included in the "BFD Configuration
sub-TLV". The "BFD Authentication sub-TLV" is used to specify which
authentication method that should be used and which shared key /
password that should be used for this particular session. How the
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key exchange is performed is out of scope of this document.
Additional OAM functions may be configured by setting the appropriate
flags in the "OAM Functions TLV", these include Performace
Measurements (packet loss and packet delay) and Fault Management
Signal handling.
By setting the PM Loss flag in the "OAM Functions TLV" and including
the "MPLS OAM PM Loss sub-TLV" one can configure the measurement
interval and loss threshold values for triggering protection.
Delay measurements are configured by setting PM Delay flag in the
"OAM Functions TLV" and including the "MPLS OAM PM Loss sub-TLV" one
can configure the measurement interval and the delay threshold values
for triggering protection.
To configure Fault Monitoring Signals and their refresh time the FMS
flag in the "OAM Functions TLV" MUST be set and the "MPLS OAM FMS
sub-TLV" included.
3.2. OAM Functions TLV
The "OAM Functions TLV" depicted below is carried as a TLV of the LSP
Echo request/response messages.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OAM Func. Type (16) (IANA) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|C|V|L|D|F| OAM Function Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ sub-TLVs ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The "OAM Functions TLV" contains a number of flags indicating which
OAM functions should be activated as well as OAM function specific
sub-TLVs with configuration parameters for the particular function.
Type: indicates a new type, the "OAM Functions TLV" (IANA to define,
suggested value 16).
Length: the length of the OAM Function Flags field including the
total length of the sub-TLVs in octets.
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OAM Function Flags: a bitmap numbered from left to right as shown in
the figure.
These flags are defined in this document:
OAM Function Flag bit# Description
--------------------- ---------------------------
0 (C) Continuity Check (CC)
1 (V) Connectivity Verification (CV)
2 (L) Performance Monitoring/Loss (PM/Loss)
3 (D) Performance Monitoring/Delay (PM/Delay)
4 (F) Fault Management Signals (FMS)
5-31 Reserved (set all to 0s)
Sub-TLVs corresponding to the different flags are as follows:
- "BFD Configuration sub-TLV", which MUST be included if the CC
OAM Function flag is set. This sub-TLV MUST carry a "BFD Local
Discriminator sub-TLV" and a "Timer Negotiation Parameters sub-
TLV" if the N flag is cleared. If the CV flag is set, the CC flag
MUST be set at the same time and a "MPLS OAM SOURCE MEP-ID sub-
TLV" MUST be included in the "BFD Configuration sub-TLV". It MAY
carry a "BFD Authentication sub-TLV" if the I flag is set. If the
I flag is set but no "BFD Authentication sub-TLV" is included
Keyed SHA1 with an empty key is used.
- "MPLS OAM PM Loss sub-TLV", which MAY be included if the PM/Loss
OAM Function flag is set. If the "MPLS OAM PM Loss sub-TLV" is
not included, default configuration values are used.
- "MPLS OAM PM Delay sub-TLV", which MAY be included if the PM/
Delay OAM Function flag is set. If the "MPLS OAM PM Delay sub-
TLV" is not included, default configuration values are used.
- "MPLS OAM FMS sub-TLV", which MAY be included if the FMS OAM
Function flag is set. If the "MPLS OAM FMS sub-TLV" is not
included, default configuration values are used.
3.2.1. BFD Configuration sub-TLV
The "BFD Configuration sub-TLV" (depicted below) is defined for BFD
OAM specific configuration parameters. The "BFD Configuration sub-
TLV" is carried as a sub-TLV of the "OAM Functions TLV".
This TLV accommodates generic BFD OAM information and carries sub-
TLVs.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BFD Conf. Type (1) (IANA) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Vers.| PHB |N|S| Reserved (set to all 0s) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ sub TLVs ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: indicates a new type, the "BFD Configuration sub-TLV" (IANA to
define, suggested value 1).
Length: indicates the length of the TLV including sub-TLVs but
excluding the Type and Length field, in octets.
Version: identifies the BFD protocol version. If a node does not
support a specific BFD version an error must be generated: "OAM
Problem/Unsupported OAM Version".
PHB: Identifies the Per-Hop Behavior (PHB) to be used for periodic
continuity monitoring messages.
BFD Negotiation (N): If set timer negotiation/re-negotiation via BFD
Control Messages is enabled, when cleared it is disabled.
Symmetric session (S): If set the BFD session MUST use symmetric
timing values.
Integrity (I): If set BFD Authentication MUST be enabled. If the
"BFD Configuration sub-TLV" does not include a "BFD Authentication
sub-TLV" the authentication MUST use Keyed SHA1 with an empty pre-
shared key (all 0s).
The "BFD Configuration sub-TLV" MUST include the following sub-TLVs
in the LSP Echo request message:
- "Local Discriminator sub-TLV";
- "Negotiation Timer Parameters sub-TLV" if N flag is cleared.
The "BFD Configuration sub-TLV" MUST include the following sub-TLVs
in the LSP Echo reply message:
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- "Local Discriminator sub-TLV;"
- "Negotiation Timer Parameters sub-TLV" if:
- N flag and S are cleared
- N flag is cleared and S flag is set and a timing value higher
than the one received needs to be used
Reserved: Reserved for future specification and set to 0.
3.2.1.1. Local Discriminator sub-TLV
The "Local Discriminator sub-TLV" is carried as a sub-TLV of the "BFD
Configuration sub-TLV" and is depicted below.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Lcl. Discr. Type (1) (IANA) | Length (4) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local Discriminator |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: indicates a new type, the "Local Discriminator sub-TLV" (IANA
to define, suggested value 1).
Length: indicates the TLV total length in octets.
Local Discriminator: A unique, nonzero discriminator value generated
by the transmitting system and referring to itself, used to
demultiplex multiple BFD sessions between the same pair of systems.
3.2.1.2. Negotiation Timer Parameters sub-TLV
The "Negotiation Timer Parameters sub-TLV" is carried as a sub-TLV of
the "BFD Configuration sub-TLV" and is depicted below.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timer Neg. Type (2) (IANA) | Length (16) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Acceptable Min. Asynchronous TX interval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Acceptable Min. Asynchronous RX interval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Required Echo TX Interval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Detect. Mult.| Reserved (set to all 0s) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: indicates a new type, the "Negotiation Timer Parameters sub-
TLV" (IANA to define, suggested value 2).
Length: indicates the length of the parameters in octets (16).
Acceptable Min. Asynchronous TX interval: in case of S (symmetric)
flag set in the "BFD Configuration" TLV, it expresses the desired
time interval (in microseconds) at which the LER initiating the
signaling intends to both transmit and receive BFD periodic control
packets. If the receiving edge LSR can not support such value, it is
allowed to reply back with an interval greater than the one proposed.
In case of S (symmetric) flag cleared in the "BFD Configuration sub-
TLV", this field expresses the desired time interval (in
microseconds) at which a edge LSR intends to transmit BFD periodic
control packets in its transmitting direction.
Acceptable Min. Asynchronous RX interval: in case of S (symmetric)
flag set in the "BFD Configuration sub-TLV", this field MUST be equal
to "Acceptable Min. Asynchronous TX interval" and has no additional
meaning respect to the one described for "Acceptable Min.
Asynchronous TX interval".
In case of S (symmetric) flag cleared in the "BFD Configuration sub-
TLV", it expresses the minimum time interval (in microseconds) at
which edge LSRs can receive BFD periodic control packets. In case
this value is greater than the "Acceptable Min. Asynchronous TX
interval" received from the other edge LSR, such edge LSR MUST adopt
the interval expressed in this "Acceptable Min. Asynchronous RX
interval".
Required Echo TX Interval: the minimum interval (in microseconds)
between received BFD Echo packets that this system is capable of
supporting, less any jitter applied by the sender as described in
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[RFC5880] sect. 6.8.9. This value is also an indication for the
receiving system of the minimum interval between transmitted BFD Echo
packets. If this value is zero, the transmitting system does not
support the receipt of BFD Echo packets. If the receiving system can
not support this value an error MUST be generated "Unsupported BFD TX
rate interval".
Detection time multiplier: The negotiated transmit interval,
multiplied by this value, provides the Detection Time for the
receiving system in Asynchronous mode.
Reserved: Reserved for future specification and set to 0.
3.2.1.3. MPLS OAM SOURCE MEP-ID sub-TLV
The "MPLS OAM SOURCE MEP-ID sub-TLV" depicted below is carried as a
sub-TLV of the "OAM Functions TLV".
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Src MEP-ID Type (3) (IANA) | Length (8) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SRC NODE ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TUNNEL ID | LSP ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: indicates a new type, the "MPLS OAM SOURCE MEP-ID sub-TLV"
(IANA to define, suggested value 3).
Length: indicates the length of the parameters in octets (8).
SRC NODE ID: 32-bit node identifier as defined in [MPLS-TP-IDENTIF].
TUNNEL ID: a 16-bit unsigned integer unique to the node as defined in
[MPLS-TP-IDENTIF].
LSP ID: a 16-bit unsigned integer unique within the Tunnel_ID as
defined in [MPLS-TP-IDENTIF].
3.2.1.4. BFD Authentication sub-TLV
The "BFD Authentication sub-TLV" is carried as a sub-TLV of the "BFD
Configuration sub-TLV" and is depicted below.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BFD Auth. Type (4) (IANA) | Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Auth Type | Auth Key ID | Reserved (0s) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: indicates a new type, the "BFD Authentication sub-TLV" (IANA to
define).
Length: indicates the TLV total length in octets. (8)
Auth Type: indicates which type of authentication to use. The same
values as are defined in section 4.1 of [RFC5880] are used.
Auth Key ID: indicates which authentication key or password
(depending on Auth Type) should be used. How the key exchange is
performed is out of scope of this document.
Reserved: Reserved for future specification and set to 0.
3.2.2. MPLS OAM PM Loss sub-TLV
The "MPLS OAM PM Loss sub-TLV" depicted below is carried as a sub-TLV
of the "OAM Functions TLV".
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PM Loss Type (2) (IANA) | Length (12) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Vers.|E|C| | Reserved (set to all 0s) | PHB |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Measurement Interval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Loss Threshold |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: indicates a new type, the "MPLS OAM PM Loss sub-TLV" (IANA to
define, suggested value 2).
Length: indicates the length of the parameters in octets (12).
Version: indicates the Loss measurement protocol version.
Configuration Flags:
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- E: exclude from the Loss Measurement all G-ACh messages
- C: require the use of a counter in the "Querier Context" field
described in [MPLS-PM]
- Remaining bits: Reserved for future specification and set to 0.
PHB: identifies the per-hop behavior of packets with loss
information.
Measurement Interval: the time interval (in microseconds) at which
Loss Measurement query messages MUST be sent on both directions. If
the edge LSR receiving the Path message can not support such value,
it can reply back with a higher interval.
Loss Threshold: the threshold value of lost packets over which
protections MUST be triggered.
3.2.3. MPLS OAM PM Delay sub-TLV
The "MPLS OAM PM Delay sub-TLV" depicted below is carried as a sub-
TLV of the "OAM Functions TLV".
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| PM Delay Type (3) (IANA) | Length (12) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Vers.| Flags | Reserved (set all to 0) | PHB |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Measurement Interval |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Delay Threshold |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: indicates a new type, the "MPLS OAM PM Delay sub-TLV" (IANA to
define, suggested value 3).
Length: indicates the length of the parameters in octets (12).
Version: indicates the Delay measurement protocol version.
Configuration Flags:
- E: exclude from the Loss Measurement all G-ACh messages
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- C: require the use of a counter in the "Querier Context" field
described in [MPLS-PM]
- Remaining bits: Reserved for future specification and set to 0.
PHB: - identifies the per-hop behavior of packets with delay
information.
Measurement Interval: the time interval (in microseconds) at which
Delay Measurement query messages MUST be sent on both directions. If
the edge LSR receiving the Path message can not support such value,
it can reply back with a higher interval.
Delay Threshold: the threshold value of measured delay (in
microseconds) over which protections MUST be triggered.
[Author's note: TBD if we want to include the timestamp format
negotiation as in [MPLS-PM] 4.2.5.]
3.2.4. MPLS OAM FMS sub-TLV
The "MPLS OAM FMS sub-TLV" depicted below is carried as a sub-TLV of
the "OAM Functions TLV".
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Fault mgmt Type (4) (IANA) | Length (8) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A|D|L|C| Reserved (set to all 0s) |E| PHB |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Refresh Timer |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: indicates a new type, the "MPLS OAM FMS sub-TLV" (IANA to
define, suggested value 4).
Length: indicates the length of the parameters in octets (8).
Signal Flags: are used to enable the following signals:
- A: Alarm Indication Signal (AIS) as described in [MPLS-FMS]
- D: Link Down Indication (LDI) as described in [MPLS-FMS]
- L: Locked Report (LKR) as described in [MPLS-FMS]
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- C: Client Signal Failure (CSF) as described in [MPLS-CSF]
- Remaining bits: Reserved for future specification and set to 0.
Configuration Flags:
- E: used to enable/disable explicitly clearing faults
- PHB: identifies the per-hop behavior of packets with fault
management information
Refresh Timer: indicates the refresh timer (in microseconds) of fault
indication messages. If the edge LSR receiving the Path message can
not support such value, it can reply back with a higher interval.
3.3. IANA Considerations
This document specifies the following new TLV types:
- "OAM Functions" type: 16;
sub-TLV types to be carried in the "OAM Functions TLV":
- "BFD Configuration" type: 1;
- "MPLS OAM PM Loss" type: 2;
- "MPLS OAM PM Delay" type: 3;
- "MPLS OAM FMS" type: 4.
sub-TLV types to be carried in the "BFD Configuration sub-TLV":
- "Local Discriminator" type: 1;
- "Negotiation Timer Parameters" type: 2;
- "MPLS OAM SOURCE MEP-ID" type: 3.
- "BFD Authentication" sub-TLV type: 4.
4. OAM configuration errors
This document specifies additional Return Codes to LSP Ping:
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- "MPLS OAM Unsupported Functionality" (IANA to assign, suggested
value 16);
- "OAM Problem/Unsupported TX rate interval" (IANA to assign,
suggested value 17.
5. Security Considerations
The signaling of OAM related parameters and the automatic
establishment of OAM entities introduces additional security
considerations to those discussed in [RFC3473]. In particular, a
network element could be overloaded, if an attacker would request
liveliness monitoring, with frequent periodic messages, for a high
number of LSPs, targeting a single network element.
Security aspects will be covered in more detailed in subsequent
versions of this document.
6. References
6.1. Normative References
[MPLS-CSF]
He, J., Li, H., and E. Bellagamba, "Indication of Client
Failure in MPLS-TP", 2010, <draft-he-mpls-tp-csf>.
[MPLS-FMS]
Swallow, G., Fulignoli, A., Vigoureux, M., Boutros, S.,
and D. Ward, "MPLS Fault Management OAM", 2009,
<draft-ietf-mpls-tp-fault>.
[MPLS-PM] Bryant, S. and D. Frost, "Packet Loss and Delay
Measurement for the MPLS Transport Profile", 2010,
<draft-ietf-mpls-tp-loss-delay>.
[MPLS-PM-Profile]
Bryant, S. and D. Frost, "A Packet Loss and Delay
Measurement Profile for MPLS-based Transport Networks",
2010, <draft-ietf-mpls-tp-loss-delay-profile>.
[MPLS-TP-IDENTIF]
Bocci, M., Swallow, G., and E. Gray, "MPLS-TP
Identifiers", 2010, <draft-ietf-mpls-tp-identifiers>.
[OAM-CONF-FWK]
Takacs, A., Fedyk, D., and J. van He, "OAM Configuration
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Framework for GMPLS RSVP-TE", 2009,
<draft-ietf-ccamp-oam-configuration-fwk>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3471] Berger, L., "Generalized Multi-Protocol Label Switching
(GMPLS) Signaling Functional Description", RFC 3471,
January 2003.
[RFC5586] Bocci, M., Vigoureux, M., and S. Bryant, "MPLS Generic
Associated Channel", RFC 5586, June 2009.
[RFC5654] Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N.,
and S. Ueno, "Requirements of an MPLS Transport Profile",
RFC 5654, September 2009.
[RFC5860] Vigoureux, M., Ward, D., and M. Betts, "Requirements for
Operations, Administration, and Maintenance (OAM) in MPLS
Transport Networks", RFC 5860, May 2010.
[RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD)", RFC 5880, June 2010.
[RSVP-TE CONF]
Bellagamba, E., Ward, D., Andersson, L., and P.
Skoldstrom, "Configuration of pro-active MPLS-TP
Operations, Administration, and Maintenance (OAM)
Functions Using RSVP-TE", 2010,
<draft-ietf-ccamp-rsvp-te-mpls-tp-oam-ext>.
6.2. Informative References
[BFD-CCCV]
Allan, D., Swallow, G., and J. Drake, "Proactive
Connectivity Verification, Continuity Check and Remote
Defect indication for MPLS Transport Profile", 2010,
<draft-ietf-mpls-tp-bfd-cc-cv-rdi>.
[BFD-Ping]
Bahadur, N., Aggarwal, R., Ward, D., Nadeau, T., Sprecher,
N., and Y. Weingarten, "LSP Ping and BFD encapsulation
over ACH", 2010,
<draft-ietf-mpls-tp-lsp-ping-bfd-procedures-02>.
[ETH-OAM] Takacs, A., Gero, B., Fedyk, D., Mohan, D., and D. Long,
"GMPLS RSVP-TE Extensions for Ethernet OAM", 2009,
<draft-ietf-ccamp-rsvp-te-eth-oam-ext>.
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[LSP Ping]
Kompella, K. and G. Swallow, "Detecting Multi-Protocol
Label Switched (MPLS) Data Plane Failures", 2006, <RFC
3479>.
[MPLS-TP OAM Analysis]
Sprecher, N., Weingarten, Y., and E. Bellagamba, "MPLS-TP
OAM Analysis", 2011, <draft-ietf-mpls-tp-oam-analysis>.
[MPLS-TP-OAM-FWK]
Bocci, M. and D. Allan, "Operations, Administration and
Maintenance Framework for MPLS-based Transport Networks",
2010, <draft-ietf-mpls-tp-oam-framework>.
[RFC4447] Martini, L., Rosen, E., El-Aawar, N., Smith, T., and G.
Heron, "Pseudowire Setup and Maintenance Using the Label
Distribution Protocol (LDP)", RFC 4447, April 2006.
[RFC5921] Bocci, M., Bryant, S., Frost, D., Levrau, L., and L.
Berger, "A Framework for MPLS in Transport Networks",
RFC 5921, July 2010.
Authors' Addresses
Elisa Bellagamba (editor)
Ericsson
Farogatan 6
Kista, 164 40
Sweden
Phone: +46 761440785
Email: elisa.bellagamba@ericsson.com
Loa Andersson
Ericsson
Farogatan 6
Kista, 164 40
Sweden
Phone:
Email: loa.andersson@ericsson.com
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Pontus Skoldstrom (editor)
Acreo AB
Electrum 236
Kista, 164 40
Sweden
Phone: +46 8 6327731
Email: pontus.skoldstrom@acreo.se
Dave Ward
Juniper
Phone:
Email: dward@juniper.net
John Drake
Juniper
Phone:
Email: jdrake@juniper.net
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