Internet DRAFT - draft-esale-mpls-app-aware-tldp
draft-esale-mpls-app-aware-tldp
MPLS Working Group Santosh Esale
INTERNET-DRAFT Raveendra Torvi
Intended Status: Proposed Standard Chris Bowers
Expires: July 30, 2015 Juniper Networks
Luay Jalil
Verizon
U. Chunduri
Ericsson Inc.
Zhenbin Li
Huawei
Kamran Raza
Cisco Systems Inc.
January 26, 2015
Application-aware Targeted LDP
draft-esale-mpls-app-aware-tldp-03
Abstract
Recent targeted LDP applications such as remote loop-free alternates
(LFA) and BGP auto discovered pseudowire may automatically establish
a tLDP session to any LSR in a network. The initiating LSR has
information about the targeted applications to administratively
control initiation of the session. However the responding LSR has no
such information to control acceptance of this session. This document
defines a mechanism to advertise and negotiate Targeted Applications
Capability during LDP session initialization. As the responding LSR
becomes aware of targeted applications, it may establish a limited
number of tLDP sessions for certain applications. In addition, each
targeted application is mapped to LDP Forwarding Equivalence Class
(FEC) Elements to advertise only necessary LDP FEC-label bindings
over the session.
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
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other groups may also distribute working documents as
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
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The list of current Internet-Drafts can be accessed at
http://www.ietf.org/1id-abstracts.html
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Copyright and License Notice
Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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publication of this document. Please review these documents
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1 Conventions Used in This Document . . . . . . . . . . . . . 4
1.2 Terminology . . . . . . . . . . . . . . . . . . . . . . . . 5
2. Targeted Application Capability . . . . . . . . . . . . . . . . 5
2.1 Encoding . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 Procedures . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.3 LDP message procedures . . . . . . . . . . . . . . . . . . . 8
2.3.1 Initialization message . . . . . . . . . . . . . . . . . 8
2.3.2 Capability message . . . . . . . . . . . . . . . . . . . 8
3. Targeted Application FEC Advertisement Procedures . . . . . . . 9
4. Interaction of Targeted Application Capabilities and State
Advertisement Control Capabilities . . . . . . . . . . . . . . 10
5. Use cases . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.1 Remote LFA Automatic Targeted session . . . . . . . . . . . 12
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5.2 FEC 129 Auto Discovery Targeted session . . . . . . . . . . 13
5.3 LDP over RSVP and Remote LFA targeted session . . . . . . . 13
5.4 mLDP node protection targeted session . . . . . . . . . . . 13
6 Security Considerations . . . . . . . . . . . . . . . . . . . . 14
7 IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 14
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 15
9 References . . . . . . . . . . . . . . . . . . . . . . . . . . 15
9.1 Normative References . . . . . . . . . . . . . . . . . . . 15
9.2 Informative References . . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16
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1 Introduction
LDP can use the extended discovery mechanism to establish a tLDP
adjacency and subsequent session as described in [RFC5036]. An LSR
initiates extended discovery by sending a tLDP Hello to a specific
address. The remote LSR decides either to accept or ignore a tLDP
Hello based on local configuration only. For an application such as
FEC 128 pseudowire, the remote LSR is configured with the source LSR
address, so the remote LSR can use that information to accept or
ignore a given tLDP Hello.
Applications such as Remote LFA and BGP auto discovered pseudowire
automatically initiate asymmetric extended discovery to any LSR in a
network based on local state only. With these applications, the
remote LSR is not explicitly configured with the source LSR address.
so the remote LSR either responds to all LDP requests or ignores all
LDP requests.
In addition, since the session is initiated and established after
adjacency formation, the responding LSR has no targeted applications
information to choose the targeted application it is configured to
support. Also, the initiating LSR may employ a limit per application
on locally initiated automatic tLDP sessions, however the responding
LSR has no such information to employ a similar limit on the incoming
tLDP sessions. Further, the responding LSR does not know whether the
source LSR is establishing a tLDP session for a configured or an
automatic application or both.
This document proposes and describes a solution to advertise Targeted
Application Capability, consisting of a targeted application list,
during initialization of a tLDP session. It also defines a mechanism
to enable a new application and disable an old application after
session establishment. This capability advertisement provides the
responding LSR with the necessary information to control the
acceptance of tLDP sessions per application. For instance, an LSR may
accept all BGP auto discovered tLDP sessions as defined in [RFC6074]
but may only accept limited number of Remote LFA tLDP sessions as
defined in [I-D.draft-ietf-rtgwg-remote-lfa]
Also, targeted LDP application is mapped to LDP FEC element type to
advertise specific application FECs only, avoiding the advertisement
of other unnecessary FECs over a tLDP session.
1.1 Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
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1.2 Terminology
This document uses terminology discussed in [I-D.draft-ietf-mpls-ldp-
ip-pw-capability] along with others defined in this document.
TAC : Targeted Application Capability
TAE : Targeted Application Element
TA-Id : Targeted Application Identifier
SAC : State Advertisement Control Capability
2. Targeted Application Capability
2.1 Encoding
An LSR MAY advertise that it is capable to negotiate a targeted LDP
application list over a tLDP session by using the Capability
Advertisement as defined in [RFC5561].
A new optional capability TLV is defined, 'Targeted Application
Capability (TAC)'. Its encoding 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|U|F| Targeted App. Cap.(IANA)| Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|S| Reserved | |
+-+-+-+-+-+-+-+-+ |
| |
~ Targeted App. Cap. data ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
As described in [RFC5561]
U: set to 1. Ignore, if not known.
F: Set to 0. Do not forward.
S: MUST be set to 1 or 0 to advertise or withdraw the Targeted
Application Capability TLV respectively.
Targeted Application Capability data:
A Targeted Applications Capability data consists of none, one
or more 32 bit Targeted Application Elements. Its encoding is
as follows:
Targeted Application Element(TAE)
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
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|E| Targ. Appl. Id | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Targeted Application Identifier (TA-Id):
a 16 bit Targeted Application Identifier value.
E-bit: The enable bit indicates whether the sender is
advertising or withdrawing the Targeted Application.
The E-bit value is used as follows:
1 - The TAE is advertising the targeted application.
0 - The TAE is withdrawing the targeted application.
The length of TAC depends on the number of TAEs. For instance,
if two TAEs are added, the length is set to 9.
2.2 Procedures
At tLDP session establishment time, a LSR MAY include a new
capability TLV, Targeted Application Capability (TAC) TLV, as an
optional TLV in the LDP Initialization message. The TAC TLV's
Capability data MUST consists of none, one or more Targeted
Application Element(TAE) each pertaining to a unique Targeted
Application Identifier(TA-Id) that a LSR supports over the session.
If the receiver LSR receives the same TA-Id in more than one TAE, it
MUST process the first element and ignore the duplicate elements. If
the receiver LSR receives an unknown TA-Id in a TAE, it MUST silently
ignore such a TAE and continue processing the rest of the TLV.
If the receiver LSR does not receive the TAC in the Initialization
message or it does not understand the TAC TLV, the TAC negotiation
MUST be considered unsuccessful and the session establishment MUST
proceed as per [RFC5036]. On the receipt of a valid TAC TLV, an LSR
MUST generate its own TAC TLV with TAEs consisting of unique TA-Ids
that it supports over the tLDP session. If there is at least one TAE
common between the TAC TLV it has received and its own, the session
MUST proceed to establishment as per [RFC5036]. If not, A LSR MUST
send a 'Session Rejected/Targeted Application Capability Mis-Match'
Notification message to the peer and close the session. The
initiating LSR SHOULD tear down the corresponding tLDP adjacency
after send or receipt of a 'Session Rejected/Targeted Application
Capability Mis-Match' Notification message to or from the responding
LSR respectively.
If both the peers advertise TAC, an LSR decides to establish or close
a tLDP session based on the negotiated targeted application list. For
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instance, suppose a initiating LSR advertises A, B and C as TA-Ids.
Further, suppose the responding LSR advertises C, D and E as TA-Ids.
Than the negotiated TA-Id, as per both the LSRs is C. In the second
instance, suppose a initiating LSR advertises A, B and C as TA-Ids
and the responding LSR, which acts as a passive LSR, advertises all
the applications - A, B, C, D and E that it supports over this
session. Than the negotiated targeted application as per both the
LSRs are A, B and C. In the last instance, suppose the initiating LSR
advertises A, B and C as a TA-Ids and the responding LSR advertises D
and E as TA-Ids, than the negotiated targeted applciations as per
both the LSRs is none. The Responding LSR sends 'Session
Rejected/Targeted Application Capability Mis-Match' Notification
message to the initiating LSR and may close the session.
When the responding LSR playing the active role in LDP session
establishment receives a 'Session Rejected/Targeted Application
Capability Mis-Match' Notification message, it MUST set its session
setup retry interval to a maximum value, as 0xffff. The session MAY
stay in non-existent state. When it detects a change in the
initiating LSR configuration or local LSR configuration pertaining to
TAC TLV, it MUST clear the session setup back off delay associated
with the session to re-attempt the session establishment. A LSR
detects configuration change on the other LSR with the receipt of
tLDP Hello message that has a higher configuration sequence number
than the earlier tLDP Hello message.
When the initiating LSR playing the active role in LDP session
establishment receives a 'Session Rejected/Targeted Application
Capability Mis-Match' Notification message, either it MUST close the
session and tear down the corresponding tLDP adjacency or it MUST set
its session setup retry interval to a maximum value, as 0xffff.
If it decides to tear down the associated tLDP adjacency, the session
is destroyed on the initiating as well as the responding LSR. The
initiating LSR MAY take appropriate actions if it is unable to bring
up the tLDP session. For instance, if an automatic session intended
to support the Remote LFA application is rejected by the responding
LSR, the initiating LSR may inform the IGP to calculate another PQ
node [I-D.draft-ietf-rtgwg-remote-lfa] for the route or set of
routes. More specific actions are a local matter and outside the
scope of this document.
If it sets the session setup retry interval to maximum, the session
MAY stay in a non-existent state. When this LSR detects a change in
the responding LSR configuration or its own configuration pertaining
to TAC TLV, it MUST clear the session setup back off delay associated
with the session to re-attempt the session establishment.
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After a tLDP session has been established with TAC capability, the
initiating and responding LSR MUST distribute FEC-label bindings for
the negotiated applications only. For instance, if the tLDP session
is established for BGP auto discovered pseudowire, only FEC 129 label
bindings MUST be distributed over the session. Similarly, a LSR
operating in downstream on demand mode MUST request FEC-label
bindings for the negotiated applications only.
If the Targeted Application Capability and Dynamic Capability, as
described in [RFC5561], are negotiated during session initialization,
TAC MAY be re-negotiated after session establishment by sending an
updated TAC TLV in LDP Capability message. The updated TAC TLV
carries TA-Ids with incremental update only. The updated TLV MUST
consist of one or more TAEs with E-bit set or E-bit off to advertise
or withdraw the new and old application respectively. This may lead
to advertisements or withdrawals of certain types of FEC-Label
bindings over the session or tear down of the tLDP adjacency and
subsequently the session.
The Targeted Application Capability is advertised on tLDP session
only. If the tLDP session changes to link session, a LSR should
withdraw it with S bit set to 0, which indicates wildcard withdrawal
of all TAE elements. Similarly, if the link session changes to tLDP,
a LSR should advertise it via the Capability message. If the
capability negotiation fails, this may lead to destruction of the
tLDP session.
Also, currently the remote LSR accepts asymmetric extended Hellos by
default or by appropriate configuration. With this document, the LSR
MUST accept tLDP hellos in order to then accept or reject the tLDP
session based on the application information.
2.3 LDP message procedures
2.3.1 Initialization message disbaled
1. The S-bit of the Targeted Application Capability TLV MUST be
set to 1 to advertise Targeted Application Capability and
SHOULD be ignored on the receipt.
2. The E-bit of the Targeted Application Element MUST be set to 1 to
enable Targeted application and SHOULD be ignored on the receipt.
3. An LSR MAY add State Control Capability by mapping Targeted
Application Element to State Advertisement Control (SAC) Elements
as defined in Section 4.
2.3.2 Capability message
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The initiating or responding LSR may re-negotiate the TAC after local
configuration change with the Capability message.
1. The S-bit of Targeted Application Capability is set to 1 or 0
to advertise or withdraw it.
2. After configuration change, If there is no common TAE between
its new TAE list and peers TAE list, the LSR MUST send a
'Session Rejected/Targeted Application Capability Mis-Match'
Notification message and close the session.
3. If there is a common TAE, a LSR MAY also update SAC Capability
based on updated TAC as described in section 4 and sends the
updated TAC and SAC capabilities in a Capability message to
the peer.
4. A receiving LSR processes the Capability message with TAC TLV.
If the S-bit is set to 0, the TAC is disabled for the session.
After that, the session may remain in established state or
torn down based on [RFC5036] rules.
5. If the S-bit is set to 1, a LSR process a list of TAEs from
TACs capability data with E-bit set to 1 or 0 to update the
peers TAE. Also, it updates the negotiated TAE list over the
tLDP session.
3. Targeted Application FEC Advertisement Procedures
The targeted LDP application MUST be mapped to LDP FEC element types
as follows to advertise only necessary LDP FEC-Label bindings over
the tLDP session.
Targeted Application Description FEC mappings
+----------------------+------------------------+------------------+
|LDPv4 Tunneling | LDP IPv4 over RSVP-TE | IPv4 FEC |
| | or other MPLS tunnel | |
+----------------------+------------------------+------------------+
| | | |
|LDPv6 Tunneling | LDP IPv6 over RSVP-TE | IPv6 FEC |
| | or other MPLS tunnel | |
+----------------------+------------------------+------------------+
|mLDP Tunneling | mLDP over RSVP-TE or | P2MP FEC |
| | or other MPLS tunnel | MP2MP FEC |
| | | HSMP-downstream |
| | | FEC |
| | | HSMP-upstream FEC|
+----------------------+------------------------+------------------+
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| | | |
|LDPv4 Remote LFA | LDPv4 over LDPv4 or | IPv4 FEC |
| | other MPLS tunnel | |
+----------------------+------------------------+------------------+
|LDPv6 Remote LFA | LDPv6 over LDPv6 or | IPv6 FEC |
| | other MPLS tunnel | |
+----------------------+------------------------+------------------+
| | | |
|LDP FEC 128 PW | LDP FEC 128 Pseudowire | FEC 128 |
+----------------------+------------------------+------------------+
| | | |
|LDP FEC 129 PW | LDP FEC 129 Pseudowire | FEC 129 |
+----------------------+------------------------+------------------+
| | | FEC types as |
|LDP Session Protection| DP session protection | per protected |
| | other MPLS tunnel | session |
+----------------------+------------------------+------------------+
|LDP ICCP | LDP Inter-chasis | |
| | control protocol | None |
+----------------------+------------------------+------------------+
| | | |
|LDP P2MP PW | LDP P2MP Pseudowire | P2MP PW FEC |
+----------------------+------------------------+------------------+
| | | P2MP FEC |
|mLDP Node Protection | mLDP node protection | MP2MP FEC |
| | | HSMP-downstream |
| | | FEC |
| | | HSMP-upstream FEC|
+----------------------+------------------------+------------------+
| | | |
|IPv4 intra-area FECs | IPv4 intra-area FECs | IPv4 FECs |
+----------------------+------------------------+------------------+
| | | |
|IPv6 intra-area FECs | IPv6 intra-area FECs | IPv6 FECs |
+----------------------+------------------------+------------------+
4. Interaction of Targeted Application Capabilities and State
Advertisement Control Capabilities
As described in this document, the set of TAEs negotiated between two
LDP peers advertising TAC represents the willingness of both peers to
advertise state information for a set of applications. The set of
applications negotiated by the TAC mechanism is symmetric between the
two LDP peers. In the absence of further mechanisms, two LDP peers
will both advertise state information for the same set of
applications.
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As described in [I-D.draft-ietf-mpls-ldp-ip-pw-capability], State
Advertisement Control(SAC) TLV can be used by an LDP speaker to
communicate its interest or disinterest in receiving state
information from a given peer for a particular application. Two LDP
peers can use the SAC mechanism to create asymmetric advertisement of
state information between the two peers.
The TAC negotiation facilitates the awareness of targeted
applications to both the peers. It enables them to advertise only
necessary LDP FEC-label bindings corresponding to negotiated
applications. With the SAC, the responding LSR is not aware of
targeted applications. Thus it may be unable to communicate its
interest or disinterest to receive state information from the peer.
However after TAC mechanism makes the responding LSR aware of
targeted application, the SAC mechanism may be used to communicate
its disinterest in receiving state information from the peer for a
particular negotiated application.
Thus, the TAC mechanism enables two LDP peers to symmetrically
advertise state information for negotiated targeted applications.
Further, the SAC mechanism enables both of them to asymmetrically
disable receipt of state information for some of the already
negotiated targeted applications. Collectively, both TAC and SAC
mechanisms can be used to control the FEC-label bindings that are
advertised over the tLDP session. For instance, suppose the
initiating LSR establishes a tLDP session to the responding LSR for
Remote LFA and FEC 129 PW targeted applications with TAC. So each LSR
advertises the corresponding FEC-Label bindings. Further, suppose
the initiating LSR is not the PQ node for responding LSRs Remote LFA
IGP calculations. In such a case, the responding LSR may use the SAC
mechanism to convey its disinterest in receiving state information
for Remote LFA targeted LDP application.
For a given tLDP session, the TAC mechanism can be used without the
SAC mechanism, and the SAC mechanism can be used without the TAC
mechanism. It is useful to discuss the behavior when TAC and SAC
mechanisms are used on the same tLDP session. The TAC mechanism MUST
take precedence over the SAC mechanism with respect to enabling
applications for which state information will be advertised. For a
tLDP session using the TAC mechanism, the LDP peers MUST NOT
advertise state information for an application that has not been
negotiated in the most recent TAE list (referred to as an un-
negotiated application). This is true even if one of the peers
announces its interest in receiving state information that
corresponds to the un-negotiated application by sending a SAC TLV.
In other words, when TAC is being used, SAC cannot and should not
enable state information advertisement for applications that have not
been enabled by TAC.
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On the other hand, the SAC mechanism MUST take precedence over the
TAC mechanism with respect to disabling state information
advertisements. If an LDP speaker has announced its disinterest in
receiving state information for a given application to a given peer
using the SAC mechanism, its peer MUST NOT send state information for
that application, even if the two peers have negotiated that the
corresponding application via the TAC mechanism.
For the purposes of determining the correspondence between targeted
applications defined in this document and application state as
defined in [I-D.draft-ietf-mpls-ldp-ip-pw-capability] an LSR MUST use
the following mappings:
LDPv4 Tunneling - IPv4 Prefix-LSPs
LDPv6 Tunneling - IPv6 Prefix-LSPs
LDPv4 Remote LFA - IPv4 Prefix-LSPs
LDPv6 Remote LFA - IPv6 Prefix-LSPs
LDP FEC 128 PW - FEC128 P2P-PW
LDP FEC 129 PW - FEC129 P2P-PW
An LSR MUST map Targeted Application to LDP capability as follows:
mLDP Tunneling - P2MP Capability, MP2MP Capability
and HSMP LSP Capability TLV
mLDP node protection - P2MP Capability, MP2MP Capability
and HSMP LSP Capability TLV
5. Use cases
5.1 Remote LFA Automatic Targeted session
An LSR determines that it needs to form an automatic tLDP session to
remote LSR based on IGP calculation as described in [I-D.draft-ietf-
rtgwg-remote-lfa] or some other mechanism, which is outside the scope
of this document. The LSR forms the tLDP adjacency and during session
setup, constructs an Initialization message with Targeted
Applications Capability (TAC) with Targeted Application Element (TAE)
as Remote LFA. The receiver LSR processes the LDP Initialization
message and verifies whether it is configured to accept a Remote LFA
tLDP session. If it is, it may further verify that establishing such
a session does not exceed the configured limit for Remote LFA
sessions. If all these conditions are met, the receiver LSR may
respond back with an Initialization message with TAC corresponding to
Remote LFA, and subsequently the session may be established.
After the session has been established with TAC capability, the
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sender and receiver LSR distribute IPv4 or IPv6 FEC label bindings
over the session. Further, the receiver LSR may determine that it
does not need these FEC label bindings. So it may disable the receipt
of these FEC label bindings by mapping targeted application element
to state control capability as described in section 4.
5.2 FEC 129 Auto Discovery Targeted session
BGP auto discovery MAY determine whether an LSR needs to initiate an
auto-discovery tLDP session with a border LSR. Multiple LSRs MAY try
to form an auto discovered tLDP session with a border LSR. So, a
service provider may want to limit the number of auto discovered tLDP
sessions a border LSR may accept. As described in Section 2, LDP may
convey targeted applications with TAC TLV to border LSR. A border LSR
may establish or reject the tLDP session based on local
administrative policy. Also, as the receiver LSR becomes aware of
targeted applications, it can also employ an administrative policy
for security. For instance, it can employ a policy 'accept all auto-
discovered session from source-list'.
Moreover, the sender and receiver LSR MUST exchange FEC 129 label
bindings only over the tLDP session.
5.3 LDP over RSVP and Remote LFA targeted session
A LSR may want to establish a tLDP session to a remote LSR for LDP
over RSVP tunneling and Remote LFA applications. The sender LSR may
add both these applications as a unique Targeted Application Element
in the Targeted Application Capability data of a TAC TLV. The
receiver LSR MAY have reached a configured limit for accepting Remote
LFA automatic tLDP sessions, but it may also be configured to accept
LDP over RSVP tunneling. In such a case, the tLDP session is formed
for both LDP over RSVP and Remote LFA applications as both needs same
FECs - IPv4 and/or IPv6.
5.4 mLDP node protection targeted session
A merge point LSR may determines that it needs to form automatic tLDP
session to the upstream point of local repair (PLR) LSR for MP2P and
MP2MP LSP node protection as described in the [I-D.draft-ietf-mpls-
mldp-node-protection]. The MPT LSR may add a new targeted LDP
application - mLDP protection, as a unique TAE in the Targeted
Application Capability Data of a TAC TLV and send it in the
Initialization message to the PLR. If the PLR is configured for mLDP
node protection and establishing this session does not exceed the
limit of either mLDP node protection sessions or automatic tLDP
sessions, the PLR may decide to accept this session. Further, the PLR
responds back with the initialization message with a TAC TLV that has
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one of the TAEs as - mLDP protection and the session proceeds to
establishment as per [RFC5036].
6 Security Considerations
The Capability procedure described in this document will apply and
does not introduce any change to LDP Security Considerations section
described in [RFC5036].
As described in [RFC5036], DoS attacks via Extended Hellos can be
addressed by filtering Extended Hellos using access lists that define
addresses with which Extended Discovery is permitted. Further, as
described in section 5.2 of this document, a LSR can employ a policy
to accept all auto-discovered Extended Hellos from the configured
source addresses list.
Also for the two LSRs supporting TAC, the tLDP session is only
established after successful negotiation of the TAC. When there is no
common targeted LDP application between two LSRs due to
administrative policy, the tLDP session is not established.
7 IANA Considerations
This document requires the assignment of a new code point for a
Capability Parameter TLVs from the IANA managed LDP registry "TLV
Type Name Space", corresponding to the advertisement of the Targeted
Applications capability. IANA is requested to assign the lowest
available value after 0x050B.
Value Description Reference
----- -------------------------------- ---------
TBD1 Targeted Applications capability [This draft]
This document requires the assignment of a new code point for a
status code from the IANA managed registry "STATUS CODE NAME SPACE"
on the Label Distribution Protocol (LDP) Parameters page,
corresponding to the notification of session Rejected/Targeted
Application Capability Mis-Match. IANA is requested to assign the
lowest available value after 0x0000004B.
Value Description Reference
----- -------------------------------- ---------
TBD2 Session Rejected/Targeted
Application Capability Mis-Match [This draft]
This document also creates a new name space 'the LDP Targeted
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Application Identifier' on the Label Distribution Protocol (LDP)
Parameters page, that is to be managed by IANA. The range is 0x0001-
0xFFFE, with the following values requested in this document.
0x0000: Reserved
0x0001: LDPv4 Tunneling
0x0002: LDPv6 Tunneling
0x0003: mLDP Tunneling
0x0004: LDPv4 Remote LFA
0x0005: LDPv6 Remote LFA
0x0006: LDP FEC 128 PW
0x0007: LDP FEC 129 PW
0x0008: LDP Session Protection
0x0009: LDP ICCP
0x000A: LDP P2MP PW
0x000B: mLDP Node Protection
0x000C: LDPv4 Intra-area FECs
0x000D: LDPv6 Intra-area FECs
0xFFFF: Reserved
Following the policies outlined in IANA, Targeted Application
Identifiers in the range 0x0001 - 0x1FFF are allocated through an
IETF Consensus action, and Targeted Application Identifiers in the
range 0x2000 - 0x7FFE are allocated as First Come First Served.
8. Acknowledgments
The authors wish to thank Nischal Sheth, Hassan Hosseini, Kishore
Tiruveedhul, Loa Andersson, Eric Rosen, Yakov Rekhter, Thomas
Beckhaus, Tarek Saad and Lizhong Jin for doing the detailed review.
Thanks to Manish Gupta and Martin Ehlers for their input to this work
and for many helpful suggestions.
9 References
9.1 Normative References
[RFC5036] Andersson, L., Ed., Minei, I., Ed., and B. Thomas, Ed.,
"LDP Specification", RFC 5036, October 2007.
[RFC5561] Thomas, B., Raza, K., Aggarwal, S., Aggarwal, R., and JL.
Le Roux, "LDP Capabilities", RFC 5561, July 2009.
[I-D.draft-ietf-mpls-ldp-ip-pw-capability] Kamran Raza, Sami Boutros,
"Disabling IPoMPLS and P2P PW LDP Application's State
Advertisement", draft-ietf-mpls-ldp-ip-pw-capability-09
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(work in progress), October 15, 2014.
[I-D.draft-ietf-mpls-mldp-node-protection] IJ. Wijnands, E. Rosen, K.
Raza, J. Tantsura, A. Atlas, Q. Zhao, "mLDP Node
Protection", draft-ietf-mpls-mldp-node-protection-02 (work
in progress), November 13, 2014.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
9.2 Informative References
[I-D.draft-ietf-rtgwg-remote-lfa] S. Bryant, C. Filsfils, S. Previdi,
M. Shand, N. So, "Remote LFA FRR", draft-ietf-rtgwg-
remote-lfa-10 (work in progress), September 26, 2014.
[RFC6074] E. Rosen, B. Davie, V. Radoaca, and W. Luo, "Provisioning,
Auto-Discovery, and Signaling in Layer 2 Virtual Private
Networks (L2VPNs)"
[RFC4762] M. Lasserre, and V. Kompella, "Virtual Private LAN Service
VPLS) Using Label Distribution Protocol (LDP) Signaling",
RFC 4762, January 2007.
[RFC4447] L. Martini, E. Rosen, El-Aawar, T. Smith, and G. Heron,
"Pseudowire Setup and Maintenance using the Label
Distribution Protocol", RFC 4447, April 2006.
[RFC5331] Aggarwal, R., Rekhter, Y., and E. Rosen, "MPLS Upstream
Label Assignment and Context-Specific Label Space", RFC
5331, August 2008.
Authors' Addresses
Santosh Esale
Juniper Networks
1194 N. Mathilda Ave.
Sunnyvale, CA 94089
US
EMail: sesale@juniper.net
Raveendra Torvi
Juniper Networks
10 Technology Park Drive.
Westford, MA 01886
US
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EMail: rtorvi@juniper.net
Chris Bowers
Juniper Networks
1194 N. Mathilda Ave.
Sunnyvale, CA 94089
US
EMail: cbowers@juniper.net
Luay Jalil
Verizon
1201 E Arapaho Rd.
Richardson, TX 75081
US
Email: luay.jalil@verizon.com
Uma Chunduri
Ericsson Inc.
300 Holger Way
San Jose, California 95134
US
Email: uma.chunduri@ericsson.com
Zhenbin Li
Huawei Bld No.156 Beiqing Rd.
Beijing 100095
China
Email: lizhenbin@huawei.com
Kamran Raza
Cisco Systems, Inc.
2000 Innovation Drive
Ottawa, ON K2K-3E8
Canada
E-mail: skraza@cisco.com
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