Revised Definition of the GMPLS Switching Capability and Type Fields
RFC 7074
Internet Engineering Task Force (IETF) L. Berger
Request for Comments: 7074 LabN
Updates: 3471, 4202, 4203, 5307 J. Meuric
Category: Standards Track Orange
ISSN: 2070-1721 November 2013
Revised Definition of the GMPLS Switching Capability and Type Fields
Abstract
GMPLS provides control for multiple switching technologies and for
hierarchical switching within a technology. GMPLS routing and
signaling use common values to indicate the type of switching
technology. These values are carried in routing protocols via the
Switching Capability field, and in signaling protocols via the
Switching Type field. While the values used in these fields are the
primary indicators of the technology and hierarchy level being
controlled, the values are not consistently defined and used across
the different technologies supported by GMPLS. This document is
intended to resolve the inconsistent definition and use of the
Switching Capability and Type fields by narrowly scoping the meaning
and use of the fields. This document updates all documents that use
the GMPLS Switching Capability and Types fields, in particular RFCs
3471, 4202, 4203, and 5307.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7074.
Berger & Meuric Standards Track [Page 1]
RFC 7074 GMPLS Switching and Type Fields Revision November 2013
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1. Introduction
Generalized Multiprotocol Label Switching (GMPLS) provides control
for multiple switching technologies. It also supports hierarchical
switching within a technology. The original GMPLS Architecture, per
[RFC3945], included support for five types of switching capabilities.
An additional type was also defined in [RFC6002]. The switching
types defined in these documents include:
1. Packet Switch Capable (PSC)
2. Layer-2 Switch Capable (L2SC)
3. Time-Division Multiplex Capable (TDM)
4. Lambda Switch Capable (LSC)
5. Fiber-Switch Capable (FSC)
6. Data Channel Switching Capable (DCSC)
Support for the original types was defined for routing in [RFC4202],
[RFC4203], and [RFC5307], where the types were represented in the
Switching Capability (Switching Cap) field. In general, hierarchy
within a type is addressed in a type-specific fashion, and a single
Switching Capability field value is defined per type. The exception
to this is PSC, which was assigned four values to indicate four
levels of hierarchy: PSC-1, PSC-2, PSC-3, and PSC-4. The same values
used in routing are defined for signaling in [RFC3471], and are
carried in the Switching Type field. Following the IANA registry, we
refer to the values used in the routing Switching Capability field
and signaling Switching Type field as Switching Types.
Berger & Meuric Standards Track [Page 2]
RFC 7074 GMPLS Switching and Type Fields Revision November 2013
In general, a Switching Type does not indicate a specific data-plane
technology; this needs to be inferred from context. For example,
L2SC was defined to cover Ethernet and ATM, and TDM was defined to
cover both SONET/SDH [RFC4606] and G.709 [RFC4328]. The basic
assumption was that different technologies of the same type would
never operate within the same control, i.e., signaling and routing
domains.
The past approach in assignment of Switching Types has proven to be
problematic from two perspectives. The first issue is that some
examples of switching technologies have different levels of switching
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