Internet DRAFT - draft-rajagopalan-pcep-rsvp-color
draft-rajagopalan-pcep-rsvp-color
PCE Working Group B. Rajagopalan
Internet-Draft V. Beeram
Intended status: Standards Track Juniper Networks
Expires: January 13, 2022 G. Mishra
Verizon Communications Inc.
July 12, 2021
Path Computation Element Protocol(PCEP) Extension for RSVP Color
draft-rajagopalan-pcep-rsvp-color-01
Abstract
This document specifies extensions to Path Computation Element
Protocol (PCEP) to carry a newly defined attribute of RSVP LSP called
'color' that can be used as a guiding criterion for selecting the LSP
as a next hop for a service route.
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 [RFC2119].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
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."
This Internet-Draft will expire on January 13, 2022.
Copyright Notice
Copyright (c) 2021 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
Rajagopalan, et al. Expires January 13, 2022 [Page 1]
Internet-Draft PCEP RSVP Color July 2021
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Protocol Operation . . . . . . . . . . . . . . . . . . . . . 3
3. TLV Format . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Usage with BGP-CT . . . . . . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 5
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
8.1. Normative References . . . . . . . . . . . . . . . . . . 5
8.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
This document defines a new RSVP LSP property, called "color", that
can be exchanged over PCEP. The 'color' field can be used as one of
the guiding criteria in selecting the LSP as a next hop for service
prefixes.
While the specific details of how the service prefixes are associated
with the appropriate RSVP LSP's are outside the scope of this
specification, the envisioned high level usage of the 'color' field
is as follows.
The service prefixes are marked with some indication of the type of
underlay they need. The underlay LSP's carry corresponding markings,
which we refer to as "color" in this specification, enabling an
ingress node to associate the service prefixes with the appropriate
underlay LSP's.
As an example, for a BGP-based service, the originating PE could
attach some community, e.g. the Extended Color Community [RFC5512]
with the service route. A receiving PE could use locally configured
policies to associate service routes carrying Extended Color
Community 'X' with underlay RSVP LSP's of color 'Y'.
While the Extended Color Community provides a convenient method to
perform the mapping, the policy on the ingress node is free to
Rajagopalan, et al. Expires January 13, 2022 [Page 2]
Internet-Draft PCEP RSVP Color July 2021
classify on any property of the route to select underlay RSVP LSP's
of a certain color.
The 'color' specified in this draft is mainly used for facilitating
underlay selection, and does not have any effect on the constraints
used for path computation.
2. Protocol Operation
The STATEFUL-PCE-CAPABILITY negotiation message is enhanced to carry
the color capability, which allows PCC & PCE to determine how
incompatibility should be handled, should only one of them support
color. An older implementation that does not recognize the new color
TLV would ignore it upon receipt. This can sometimes result in
undesirable behavior. For example, if PCE passes color to a PCC that
does not understand colors, the LSP may not be used as intended. A
PCE that clearly knows the PCC's color capability can handle such
cases better, and vice versa. Following are the rules for handling
mismatch in color capability.
A PCE that has color capability MUST NOT send color TLV to a PCC that
does not have color capability. A PCE that does not have color
capability can ignore color marking reported by PCC.
When a PCC is interacting with a PCE that does not have color
capability, the PCC
o SHOULD NOT report color to the PCE.
o MUST NOT override the local color, if it is configured, based on
any messages coming from the PCE.
The actual color value itself is carried in a newly defined TLV in
the LSP Object defined in [RFC8231].
If a PCC is unable to honor a color value passed in an LSP Update
request, the PCC must keep the LSP in DOWN state, and include an LSP
Error Code value of "Unsupported Color" [Value to be assigned by
IANA] in LSP State Report message.
If an RSVP tunnel has multiple LSP's associated with it, the PCE
should designate one of the LSP's as primary, and attach the color
with that LSP. If PCC receives color TLV for an LSP that it treats
as secondary, it SHOULD respond with an error code of 4 (Unacceptable
Parameters).
Rajagopalan, et al. Expires January 13, 2022 [Page 3]
Internet-Draft PCEP RSVP Color July 2021
3. TLV Format
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Color |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Color TLV in LSP Object
Type has the value [TO-BE-ASSIGNED-BY-IANA]. Length carries a value
of 4. The 'color' field is 4-bytes long, and carries the actual
color value.
Section 7.1.1 of RFC8231 [RFC8231] defines STATEFUL-PCE-CAPABILITY
flags. The following flag is used to indicate if the speaker
supports color capability:
C-bit (TO-BE-ASSIGNED-BY-IANA): A PCE/PCC that supports color
capability must turn on this bit.
4. Usage with BGP-CT
RSVP LSP's marked with color can also be used for inter-domain
service mapping as defined in BGP-CT
[I-D.kaliraj-idr-bgp-classful-transport-planes]. In BGP-CT, the
mapping community of the service route is used to select a
"resolution scheme", which in turn selects LSP's of various
"transport classes" in the defined order of preference. The 'color'
field defined in this specification could be used to associate the
RSVP LSP with a particular transport class.
A colored RSVP LSP can also be exported into BGP-CT for inter-domain
classful transport.
5. Security Considerations
This document defines a new TLV for color, and a new flag in
capability negotiation, which do not add any new security concerns
beyond those discussed in [RFC5440], [RFC8231] and [RFC8281].
An unauthorized PCE may maliciously associate the LSP with an
incorrect color. The procedures described in [RFC8253] and [RFC7525]
can be used to protect against this attack.
Rajagopalan, et al. Expires January 13, 2022 [Page 4]
Internet-Draft PCEP RSVP Color July 2021
6. IANA Considerations
IANA is requested to assign code points for the following:
o Code point for "Color" TLV from the sub-registry "PCEP TLV Type
Indicators".
o C-bit value from the sub-registry "STATEFUL-PCE-CAPABILITY TLV
Flag Field".
o An error code for "Unsupported color" from the sub-registry "LSP-
ERROR-CODE TLV Error Code Field".
7. Acknowledgments
The authors would like to thank Kaliraj Vairavakkalai, Colby Barth &
Natrajan Venkataraman for their review & suggestions, which helped
improve this specification.
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol (PCEP)", RFC 5440,
DOI 10.17487/RFC5440, March 2009,
<https://www.rfc-editor.org/info/rfc5440>.
[RFC5512] Mohapatra, P. and E. Rosen, "The BGP Encapsulation
Subsequent Address Family Identifier (SAFI) and the BGP
Tunnel Encapsulation Attribute", RFC 5512,
DOI 10.17487/RFC5512, April 2009,
<https://www.rfc-editor.org/info/rfc5512>.
[RFC7525] Sheffer, Y., Holz, R., and P. Saint-Andre,
"Recommendations for Secure Use of Transport Layer
Security (TLS) and Datagram Transport Layer Security
(DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May
2015, <https://www.rfc-editor.org/info/rfc7525>.
Rajagopalan, et al. Expires January 13, 2022 [Page 5]
Internet-Draft PCEP RSVP Color July 2021
[RFC8231] Crabbe, E., Minei, I., Medved, J., and R. Varga, "Path
Computation Element Communication Protocol (PCEP)
Extensions for Stateful PCE", RFC 8231,
DOI 10.17487/RFC8231, September 2017,
<https://www.rfc-editor.org/info/rfc8231>.
[RFC8253] Lopez, D., Gonzalez de Dios, O., Wu, Q., and D. Dhody,
"PCEPS: Usage of TLS to Provide a Secure Transport for the
Path Computation Element Communication Protocol (PCEP)",
RFC 8253, DOI 10.17487/RFC8253, October 2017,
<https://www.rfc-editor.org/info/rfc8253>.
[RFC8281] Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "Path
Computation Element Communication Protocol (PCEP)
Extensions for PCE-Initiated LSP Setup in a Stateful PCE
Model", RFC 8281, DOI 10.17487/RFC8281, December 2017,
<https://www.rfc-editor.org/info/rfc8281>.
8.2. Informative References
[I-D.kaliraj-idr-bgp-classful-transport-planes]
Vairavakkalai, K., Venkataraman, N., Rajagopalan, B.,
Mishra, G., Khaddam, M., Xu, X., and R. J. Szarecki, "BGP
Classful Transport Planes", draft-kaliraj-idr-bgp-
classful-transport-planes-07 (work in progress), February
2021.
Authors' Addresses
Balaji Rajagopalan
Juniper Networks
Email: balajir@juniper.net
Vishnu Pavan Beeram
Juniper Networks
Email: vbeeram@juniper.net
Gyan Mishra
Verizon Communications Inc.
Email: gyan.s.mishra@verizon.com
Rajagopalan, et al. Expires January 13, 2022 [Page 6]
