RFC 6003 PROPOSED STANDARD GMPLS · ETHERNET · SIGNALING
Ethernet TSPEC: Ethernet Traffic Parameters
How a GMPLS signaling request states the Ethernet traffic rates it needs.
RFC EDITOR
Papadimitriou, D., "Ethernet Traffic Parameters", RFC 6003, DOI 10.17487/RFC6003, October 2010, <https://www.rfc-editor.org/info/rfc6003>.
BIBTEX
@misc{rfc6003,
series = {Request for Comments},
number = 6003,
howpublished = {RFC 6003},
publisher = {RFC Editor},
doi = {10.17487/RFC6003},
url = {https://www.rfc-editor.org/info/rfc6003},
author = {D. Papadimitriou},
title = {{Ethernet Traffic Parameters}},
pagetotal = 14,
year = 2010,
month = oct,
} LINEAGE · FROM THE RFC INDEXOpen full graph →
RFC text
Contents
Internet Engineering Task Force (IETF) D. Papadimitriou
Request for Comments: 6003 Alcatel-Lucent
Updates: 3471, 3473 October 2010
Category: Standards Track
ISSN: 2070-1721
Ethernet Traffic Parameters
Abstract
This document describes the support of Metro Ethernet Forum (MEF)
Ethernet traffic parameters as described in MEF10.1 when using
Generalized Multi-Protocol Label Switching (GMPLS) Resource
ReSerVation Protocol - Traffic Engineering (RSVP-TE) signaling.
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/rfc6003.
Copyright Notice
Copyright (c) 2010 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
(http://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.
1. Introduction
Per [RFC3471], Generalized Multi-Protocol Label Switching (GMPLS)
allows the inclusion of technology-specific parameters in signaling.
This document introduces Ethernet SENDER_TSPEC and FLOWSPEC-specific
objects in support of Metro Ethernet Forum (MEF) Ethernet traffic
parameters as specified in [MEF10.1] and ITU-T Ethernet Service
Switching as discussed in [RFC6004]. For example:
o For Ethernet Private Line (EPL) services [MEF6], these traffic
parameters are applicable to each Ethernet Virtual Connection
(EVC) crossing a given port.
o For Ethernet Virtual Private Line (EVPL) services [MEF6], these
traffic parameters are applicable per Ethernet Virtual Connection
(EVC) with a single or multiple Class of Service (CoS),
independent of its associated Virtual LAN ID (VID) or set of VIDs.
Association between EVC and VIDs is detailed in [MEF10.1]. The
format and encoding of the VID (or set of VIDs) is documented in a
companion document [RFC6004].
This does not preclude broader usage of the Ethernet SENDER_TSPEC and
FLOWSPEC-specific objects specified this document. For instance,
they may also be used for signaling Ethernet Label Switched Paths
(LSPs), in the Generalized Label Request (see [RFC3471]), the
Switching Type field is set to Layer 2 Switching Capability (L2SC)
and the LSP Encoding Type field to Ethernet.
2. 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].
Moreover, the reader is assumed to be familiar with the terminology
in [MEF10.1] as well as in [RFC3471] and [RFC3473].
3. Overview
In GMPLS RSVP-TE [RFC3473], the SENDER_TSPEC object is used on a Path
message to indicate the bandwidth that is requested for the LSP being
established, and the FLOWSPEC object is used on a Resv message to
indicate the bandwidth actually reserved for the LSP. The Ethernet
SENDER_TSPEC/FLOWSPEC object includes the Ethernet link type
(switching granularity) of the requested LSP and the MTU value for
the LSP. Other information about the requested bandwidth
characteristics of the LSP are carried in the Bandwidth Profile as a
TLV within the Ethernet SENDER_TSPEC/FLOWSPEC object.
The Ethernet SENDER_TSPEC/FLOWSPEC object includes the Ethernet link
type (switching granularity) of the requested LSP and the MTU value
for the LSP.
The Bandwidth Profile defines the set of traffic parameters
applicable to a sequence of Service Frames, referred to as bandwidth
profile parameters (as specified in [MEF10.1]):
o Committed Rate: indicates the rate at which traffic commits to be
sent to the Ethernet LSP. The committed rate is described in
terms of the CIR (Committed Information Rate) and CBS (Committed
Burst Size) traffic parameters.
o CIR is defined as the average rate (in bytes per unit of time)
up to which the network is committed to transfer frames and
meets its performance objectives.
o CBS defines a limit on the maximum number of information units
(e.g., bytes) available for a burst of frames sent at the
interface speed to remain CIR-conformant.
o Excess Rate: indicates the extent by which the traffic sent on an
Ethernet LSP exceeds the committed rate. The Excess Rate is
described in terms of the EIR (Excess Information Rate) and EBS
(Excess Burst Size) traffic parameters.
o EIR is defined as the average rate (in bytes per unit of time),
in excess of the CIR, up to which the network may transfer
frames without any performance objectives.
o EBS defines a limit on the maximum number of information units
(e.g., bytes) available for a burst of frames sent at the
interface speed to remain EIR-conformant.
o Color mode (CM): indicates whether the "color-aware" or "color-
blind" property is employed by the bandwidth profile.
o Coupling flag (CF): allows the choice between two modes of
operation of the rate enforcement algorithm.
4. Ethernet SENDER_TSPEC Object
The Ethernet SENDER_TSPEC object (Class-Num = 12, Class-Type = 6) 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length | Class-Num (12)| C-Type (6) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Switching Granularity | MTU |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ TLVs ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Switching Granularity (SG): 16 bits
This field indicates the type of link that comprises the requested
Ethernet LSP.
The permitted Ethernet Link Type values are:
Value Switching Granularity
----- ---------------------
0 Provided in signaling. See [RFC6004].
1 Ethernet Port (for port-based service)
2 Ethernet Frame (for EVC-based service)
255 Reserved
Values 0 to 2 are specified by the present document. Values 3
through 239 are to be assigned by IANA via Standards Action
[RFC5226]. Value 255 is reserved by the present document (its
Length is to be determined by the RFC that will specify it).
Values 240 through 254 are reserved for vendor-specific use.
Values 256 through 65535 are not assigned at this time.
MTU: 16 bits
This is a two-octet value indicating the MTU in octets.
The MTU field MUST NOT take a value smaller than 46 bytes for
Ethernet v2 [ETHv2] and 38 bytes for IEEE 802.3 [IEEE802.3].
TLV (Type-Length-Value):
The Ethernet SENDER_TSPEC object MUST include at least one TLV and
MAY include more than one TLV.
Each TLV MUST have 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Value ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 16 bits
Defined values are:
Type Length Format Description
------------------------------------------------------
0 - Reserved Reserved value
1 - Reserved Reserved value
2 24 see Section 3.1 Ethernet Bandwidth
Profile [MEF10.1]
3 8 [RFC6004] Layer 2 Control
Protocol (L2CP)
255 - Reserved Reserved value
Values 0, 1, and 255 are reserved by the present document. Values
2 and 3 are specified by the present document.
Values 4 through 239 are to be assigned by IANA via Standards
Action [RFC5226].
Values 240 through 254 are reserved for vendor-specific use.
Values 256 through 65535 are not assigned at this time.
Length: 16 bits
Indicates the length in bytes of the whole TLV including the Type
and Length fields. A value field whose length is not a multiple
of four MUST be zero-padded (with trailing zeros) so that the TLV
is four-octet aligned.
4.1. Ethernet Bandwidth Profile TLV
The Type 2 TLV specifies the Ethernet Bandwidth Profile (BW profile).
It defines an upper bound on the volume of the expected service
frames belonging to a particular Ethernet service instance. The
Ethernet SENDER_TSPEC object MAY include more than one Ethernet
Bandwidth Profile TLV.
The Type 2 TLV 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Profile | Index | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CIR |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| CBS |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| EIR |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| EBS |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Profile: 8 bits
This field is defined as a bit vector of binary flags. The
following flags are defined:
Flag 1 (bit 0): Coupling Flag (CF)
Flag 2 (bit 1): Color Mode (CM)
Where bit 0 is the low order bit. Other flags are reserved, they
SHOULD be set to zero when sent, and SHOULD be ignored when
received.
A flag is set to value 1 to indicate that the corresponding
metering profile is requested.
The Flag 1 (CF) allows the choice between two modes of operation
of the rate enforcement algorithm.
The Flag 2 (CM) indicates whether the color-aware or color-blind
property [MEF10.2] is employed by the bandwidth profile. When
Flag 2 is set to value 0 (1), the bandwidth profile algorithm is
said to be in color-blind (color-aware) mode.
Index: 8 bits
The Index field is used to reference bandwidth allocated for a
given traffic class in case a multiple-class LSP is being
requested. The Index field value MUST correspond to at least one
of the Class-Type values included either in the CLASSTYPE object
[RFC4124] or in the EXTENDED_CLASSTYPE object [MCOS].
A given index value j can be associated to at most N Class-Type
values CTi (i =< N) of the EXTENDED_CLASSTYPE object. This
association applies when a set of one or more CTIs maps to a
single (shared) BW profile. An example of value setting consists
in assigning an arbitrary value comprised within the range
[0x08,0xF8] associated to a set of CTi, the values in the range
[0xF8,0xFF] being selected for reserved sets. This allows mapping
to one of 248 predefined CTi sets.
A given index value j can be associated to a single CTi (1:1
correspondence). In this case, the index value setting consists
in assigning the 3 least significant bits of the Index field
itself to the CTi value itself (comprised in the range
[0x00,0x07]). This applies in case a single CTi maps a single
(dedicated) BW profile or multiple (dedicated) BW profiles. In
the former case, the Ethernet SENDER_TSPEC object includes a
single Ethernet Bandwidth Profile TLV. In the latter case, the
Ethernet SENDER_TSPEC includes a set of more than one Ethernet
Bandwidth Profile TLVs (whose respective index value is associated
to a single CTi value).
Note that the current specification allows for combining shared
and dedicated BW profiles to the same LSP. That is, an Ethernet
SENDER_TSPEC object MAY include multiple Ethernet Bandwidth
Profile TLVs whose respective index can be associated on a 1:1
basis to a single CTi or to a set of multiple CTis.
For each subobject of the EXTENDED_CLASSTYPE object [MCOS]:
o Each CTi value SHOULD correspond 1:1 to the MEF Customer
Edge VLAN CoS (CE-VLAN CoS).
o The BW requested per CTi field MAY be used for bandwidth
accounting purposes.
By default, the value of the Index field MUST be set to 0.
Reserved: 16 bits
These bits SHOULD be set to zero when sent and MUST be ignored
when received.
CIR (Committed Information Rate): 32 bits
The value of the CIR is in units of bytes per second. The CIR is
encoded as a 32-bit IEEE single-precision floating-point number
(see [RFC4506]).
The CIR value MUST be greater than or equal to 0.
CBS (Committed Burst Size): 32 bits
The value of the CBS is in units of bytes. The CBS is encoded as
a 32-bit IEEE single-precision floating-point number (see
[RFC4506]).
When CIR is strictly greater than 0 (CIR > 0), the CBS MUST be
greater than or equal to the maximum frame size.
EIR (Excess Information Rate): 32 bits
The value of the EIR is in units of bytes per second. The EIR is
encoded as a 32-bit IEEE single-precision floating-point number
(see [RFC4506]).
The EIR value MUST be greater than or equal to 0.
EBS (Excess Burst Size): 32 bits
The value of the EBS is in units of bytes. The EBS is encoded as
a 32-bit IEEE single-precision floating-point number (see
[RFC4506]).
When EIR is strictly greater than 0 (EIR > 0), the EBS MUST be
greater than or equal to the maximum frame size.
5. Ethernet FLOWSPEC Object
The Ethernet FLOWSPEC object (Class-Num = 9, Class-Type = 6) has the
same format as the Ethernet SENDER_TSPEC object.
6. Ethernet ADSPEC Object
There is no ADSPEC object associated with the Ethernet SENDER_TSPEC
object.
Either the ADSPEC object is omitted or an IntServ ADSPEC with the
Default General Characterization Parameters and Guaranteed Service
fragment is used, see [RFC2210].
7. Processing
The Ethernet SENDER_TSPEC and FLOWSPEC objects specified in this
document MAY be used for signaling Ethernet LSP. For signaling such
an LSP, in the Generalized LABEL_REQUEST object (see [RFC3471]), the
Switching Type field MUST be set to the value 51 (L2SC) and the LSP
Encoding Type field MUST be set to the value 2 (Ethernet).
The Ethernet SENDER_TSPEC object carries the traffic specification
generated by the RSVP session sender. The Ethernet SENDER_TSPEC
object SHOULD be forwarded and delivered unchanged to both
intermediate and egress nodes.
The Ethernet FLOWSPEC object carries reservation request information
generated by receivers. As with any FLOWSPEC object, the Ethernet
FLOWSPEC object flows upstream toward the ingress node.
Intermediate and egress nodes MUST verify that the node itself and
the interfaces on which the LSP will be established can support the
requested Switching Granularity, MTU and values included in subobject
TLVs. These nodes MUST be configured with the same predefined CT
sets as the index value signaled as part of the Index field of the
Ethernet Bandwidth Profile TLV (see Section 4.1). If the requested
value(s) cannot be supported, the receiver node MUST generate a
PathErr message with the error code "Traffic Control Error" and the
error value "Service unsupported" (see [RFC2205]).
In addition, if the MTU field is received with a value smaller than
the minimum transfer unit size of the Ethernet frame (e.g., 46 bytes
for Ethernet v2, 38 bytes for IEEE 802.3), the node MUST generate a
PathErr message with the error code "Traffic Control Error" and the
error value "Bad Tspec value" (see [RFC2205]).
Error processing of the CLASSTYPE object follows rules defined in
[RFC4124]. Error processing of the EXTENDED_CLASSTYPE object follows
rules defined in [MCOS]. Moreover, a Label Switching Router (LSR)
receiving a Path message with the EXTENDED_CLASSTYPE object, which
recognizes the object and the particular Class-Type but does detect a
mismatch in the index values, MUST send a PathErr message towards the
sender with the error code "Extended Class-Type Error" and the error
value "Class-Type mismatch" (see [RFC2205]).
8. Security Considerations
This document introduces no new security considerations to [RFC3473].
GMPLS security is described in Section 11 of [RFC3471] and refers to
[RFC3209] for RSVP-TE. Further details of MPLS-TE and GMPLS security
can be found in [RFC5920].
9. IANA Considerations
IANA maintains registries and sub-registries for RSVP-TE as used by
GMPLS. IANA has made allocations from these registries as set out in
the following sections.
9.1. RSVP Objects Class Types
This document introduces two new Class Types for existing RSVP
objects. IANA has made allocations from the "Resource ReSerVation
Protocol (RSVP) Parameters" registry using the "Class Names, Class
Numbers, and Class Types" sub-registry.
Class Number Class Name Reference
------------ ----------------------- ---------
9 FLOWSPEC [RFC2205]
Class Type (C-Type):
6 Ethernet SENDER_TSPEC [RFC6003]
Class Number Class Name Reference
------------ ----------------------- ---------
12 SENDER_TSPEC [RFC2205]
Class Type (C-Type):
6 Ethernet SENDER_TSPEC [RFC6003]
9.2. Ethernet Switching Granularities
IANA maintains a registry of GMPLS parameters called "Generalized
Multi-Protocol Label Switching (GMPLS) Signaling Parameters".
IANA has created a new sub-registry called "Ethernet Switching
Granularities" to contain the values that may be carried in the
Switching Granularity field of the Ethernet SENDER_TSPEC object.
Values are as follows:
0-2 See below.
3-239 Unassigned
240-254 Reserved for Vendor-Specific Use
255 Reserved
256-65535 Not assigned at this time
The registration procedure is Standards Action.
Initial entries in this sub-registry are as follows:
Value Switching Granularity Reference
----- -------------------------------------- ------------------
0 Provided in signaling. [RFC6003][RFC6004]
1 Ethernet Port (for port-based service) [RFC6003]
2 Ethernet Frame (for EVC-based service) [RFC6003]
255 Reserved [RFC6003]
9.3. Ethernet Sender TSpec TLVs
IANA maintains a registry of GMPLS parameters called "Generalized
Multi-Protocol Label Switching (GMPLS) Signaling Parameters".
IANA has created a new sub-registry called "Ethernet Sender TSpec
TLVs / Ethernet Flowspec TLVs" to contain the TLV type values for
TLVs carried in the Ethernet SENDER_TSPEC object.
Values are as follows:
0-3 See below.
4-239 Unassigned
240-254 Reserved for Vendor-Specific Use
255 Reserved
256-65535 Not assigned at this time
The registration procedure is Standards Action.
Initial entries in this sub-registry are as follows:
Type Description Reference
----- -------------------------------- ---------
0 Reserved [RFC6003]
1 Reserved [RFC6003]
2 Ethernet Bandwidth Profile [RFC6003]
3 Layer 2 Control Protocol (L2CP) [RFC6003]
255 Reserved [RFC6003]
9.4. Ethernet Bandwidth Profiles
IANA maintains a registry of GMPLS parameters called "Generalized
Multi-Protocol Label Switching (GMPLS) Signaling Parameters".
IANA has created a new sub-registry called "Ethernet Bandwidth
Profiles" to contain bit flags carried in the Ethernet Bandwidth
Profile TLV of the Ethernet SENDER_TSPEC object.
Bits are to be allocated by IETF Standards Action. Bits are numbered
from bit 0 as the low order bit. Initial entries are as follows:
Bit Hex Description Reference
--- ---- -------------------------- -------------
0 0x01 Coupling Flag (CF) [RFC6003]
1 0x02 Color Mode (CM) [RFC6003]
10. Acknowledgments
Many thanks to Adrian Farrel for his comments. Lou Berger provided
the input on control traffic processing.
11. References
11.1. Normative References
[MEF10.1] The MEF Technical Specification, "Ethernet Services
Attributes Phase 2", MEF 10.1, November 2006.
[RFC2205] Braden, R., Ed., Zhang, L., Berson, S., Herzog, S., and S.
Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
Functional Specification", RFC 2205, September 1997.
[RFC2210] Wroclawski, J., "The Use of RSVP with IETF Integrated
Services", RFC 2210, September 1997.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, December 2001.
[RFC3471] Berger, L., Ed., "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Functional Description", RFC
3471, January 2003.
[RFC3473] Berger, L., Ed., "Generalized Multi-Protocol Label
Switching (GMPLS) Signaling Resource ReserVation Protocol-
Traffic Engineering (RSVP-TE) Extensions", RFC 3473,
January 2003.
[RFC4124] Le Faucheur, F., Ed., "Protocol Extensions for Support of
Diffserv-aware MPLS Traffic Engineering", RFC 4124, June
2005.
[RFC4506] Eisler, M., Ed., "XDR: External Data Representation
Standard", STD 67, RFC 4506, May 2006.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
[RFC6004] Berger, L. and D. Fedyk, "Generalized MPLS (GMPLS) Support
for Metro Ethernet Forum and G.8011 Ethernet Services",
RFC 6004, October 2010.
11.2. Informative References
[ETHv2] Digital, Intel, and Xerox, "The Ethernet -- A Local Area
Network: Data Link Layer and Physical Layer
Specifications", Version 2.0, November 1982.
[IEEE802.3]
IEEE 802.3 LAN/MAN CSMA/CD (Ethernet) Access Method, IEEE
Standard for Information technology- Specific requirements
- Part 3: Carrier Sense Multiple Access with Collision
Detection (CMSA/CD) Access Method and Physical Layer
Specifications, IEEE 802.3-2008.
[MCOS] Minei, I., Gan, D., Kompella, K., and X. Li, "Extensions
for Differentiated Services-aware Traffic Engineered
LSPs", Work in Progress, June 2006.
[MEF6] The Metro Ethernet Forum, "Ethernet Services Definitions -
Phase I", MEF 6, June 2004.
[MEF10.2] The MEF Technical Specification, "Ethernet Services
Attributes Phase 2", MEF 10.2, October 2009.
[RFC5920] Fang, L., Ed., "Security Framework for MPLS and GMPLS
Networks", RFC 5920, July 2010.
Author's Address
Dimitri Papadimitriou
Alcatel-Lucent Bell
Copernicuslaan 50
B-2018 Antwerpen, Belgium
Phone: +32 3 2408491
EMail: dimitri.papadimitriou@alcatel-lucent.be
AI ELI5
On this page
PROBLEMGMPLS signaling had no way to carry the Metro Ethernet Forum traffic parameters, such as committed and excess rates, when setting up an Ethernet path.
MECHANISMIt defines Ethernet SENDER_TSPEC and FLOWSPEC objects (C-Type 6) holding a switching granularity, an MTU and TLVs, chiefly an Ethernet Bandwidth Profile TLV with CIR, CBS, EIR and EBS.
WHY IT MATTERSEthernet LSPs can request and reserve bandwidth in MEF terms. The RFC updates RFC 3471 and RFC 3473.
§1Purpose and Scope
GMPLS lets signaling carry technology-specific parameters (RFC 3471). This document adds Ethernet SENDER_TSPEC and FLOWSPEC objects to support the Metro Ethernet Forum (MEF) traffic parameters of MEF 10.1 and ITU-T Ethernet Service Switching (RFC 6004).
For Ethernet Private Line services the parameters apply to each Ethernet Virtual Connection (EVC) crossing a port. For Ethernet Virtual Private Line services they apply per EVC, with a single or multiple Class of Service, independent of the VLAN IDs. The objects can also signal Ethernet Label Switched Paths (LSPs) more broadly.
This adds a new form field to the messages that set up network paths, so you can write down how much Ethernet traffic the path should carry.
§3How the Objects and the Bandwidth Profile Fit In
In GMPLS RSVP-TE (RFC 3473), the SENDER_TSPEC object on a Path message says what bandwidth is requested, and the FLOWSPEC object on a Resv message says what was actually reserved. The Ethernet versions carry the link type (switching granularity) and an MTU, with the bandwidth details in a Bandwidth Profile TLV.
The Bandwidth Profile uses the MEF 10.1 parameters. The committed rate is described by CIR (Committed Information Rate, an average rate the network commits to carry) and CBS (Committed Burst Size). The excess rate is described by EIR (Excess Information Rate, an average rate above CIR with no performance objectives) and EBS (Excess Burst Size). The Color Mode says whether the profile is color-aware or color-blind, and the Coupling Flag chooses between two modes of the rate enforcement algorithm.
It is like a phone plan: a rate you are promised, a bit extra you may use with no promise, and a limit on how big a quick burst can be.
§4The Ethernet SENDER_TSPEC Object
The Ethernet SENDER_TSPEC object has Class-Num 12 and Class-Type 6. After the standard header come a 16-bit Switching Granularity, a 16-bit MTU, and TLVs. There MUST be at least one TLV.
Switching Granularity values are 0 (provided in signaling, see RFC 6004), 1 (Ethernet Port, for port-based service) and 2 (Ethernet Frame, for EVC-based service). The MTU is in octets and MUST NOT be smaller than 46 bytes for Ethernet v2 or 38 bytes for IEEE 802.3.
Each TLV has a 16-bit Type and a 16-bit Length that covers the whole TLV, and values are zero-padded to a multiple of four octets. Type 2 is the Ethernet Bandwidth Profile (length 24) and Type 3 is the Layer 2 Control Protocol (length 8, defined in RFC 6004). Types 0, 1 and 255 are reserved.
The form has a box for what kind of link you want, a box for the biggest message size, and then a list of extra notes, each in its own labeled slot.
§4.1The Ethernet Bandwidth Profile TLV
The Type 2 TLV carries an 8-bit Profile bit vector, an 8-bit Index, 16 reserved bits, and four 32-bit values: CIR, CBS, EIR and EBS. Profile bit 0 is the Coupling Flag and bit 1 is the Color Mode; a Color Mode of 0 means color-blind and 1 means color-aware. Other flags SHOULD be zero when sent and ignored when received. An object MAY hold more than one such TLV.
CIR and EIR are in bytes per second, CBS and EBS in bytes, all encoded as 32-bit IEEE single-precision floating-point numbers (RFC 4506). CIR and EIR MUST be at least 0. When CIR is greater than 0, CBS MUST be at least the maximum frame size, and likewise EBS when EIR is greater than 0.
The Index ties a profile to the traffic class in a multiple-class LSP and MUST match a Class-Type in the CLASSTYPE or EXTENDED_CLASSTYPE object. By default it MUST be 0. One index can map to a set of class types sharing a profile, or to a single class type with a dedicated profile.
This is the actual price list: how fast, how big a burst, and extra allowed speed. Each number is stored in a fixed-size slot.
| Field | Name | Size | Value | Description |
|---|---|---|---|---|
PROFILE | Profile | 1 byte | Flags: bit 0 Coupling Flag, bit 1 Color Mode. | |
INDEX | Index | 1 byte | Refers to the traffic class; default 0. | |
RESERVED | Reserved | 2 bytes | Zero when sent, ignored when received. | |
CIR | CIR | 4 bytes | Committed rate, bytes per second. | |
CBS | CBS | 4 bytes | Committed burst size, bytes. | |
EIR | EIR | 4 bytes | Excess rate, bytes per second. | |
EBS | EBS | 4 bytes | Excess burst size, bytes. |
§5FLOWSPEC, ADSPEC and Processing Rules
The Ethernet FLOWSPEC object has Class-Num 9 and Class-Type 6, and the same format as the SENDER_TSPEC. There is no Ethernet ADSPEC: it is either omitted or an IntServ ADSPEC is used.
When signaling an Ethernet LSP, the Generalized LABEL_REQUEST Switching Type MUST be 51 (L2SC) and the LSP Encoding Type MUST be 2 (Ethernet). The SENDER_TSPEC SHOULD be forwarded unchanged to intermediate and egress nodes, and the FLOWSPEC flows upstream toward the ingress.
Nodes MUST check that they and their interfaces can support the requested granularity, MTU and TLV values. If not, the receiver MUST send a PathErr with error code Traffic Control Error and value Service unsupported. An MTU below the minimum Ethernet frame size gives Traffic Control Error with Bad Tspec value. A mismatch in index values with an EXTENDED_CLASSTYPE object gives Extended Class-Type Error, Class-Type mismatch.
Each switch along the way checks whether it can honor the request. If it cannot, it sends back a note saying which part it could not do.
§8Security and IANA Considerations
The document introduces no new security considerations beyond RFC 3473. GMPLS security is described in Section 11 of RFC 3471, and further details are in RFC 5920.
IANA assigned C-Type 6 under both the FLOWSPEC (class 9) and SENDER_TSPEC (class 12) classes. It created registries for Ethernet Switching Granularities, Ethernet Sender TSpec TLVs and Ethernet Bandwidth Profile bit flags (CF at 0x01 and CM at 0x02), all with Standards Action as the registration procedure.
Nothing new to worry about here beyond what the older rules already cover. The official lists were extended so that everyone uses the same numbers.
§7References
[RFC2205]RFC 2205Braden, R., Ed., et al., "Resource ReSerVation Protocol (RSVP) -- Version 1 Functional Specification", RFC 2205, September 1997.September 1997[RFC3471]RFC 3471Berger, L., Ed., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Functional Description", RFC 3471, January 2003.February 2003[RFC3473]RFC 3473Berger, L., Ed., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Resource ReserVation Protocol-Traffic Engineering (RSVP-TE) Extensions", RFC 3473, January 2003.February 2003[RFC4124]RFC 4124Le Faucheur, F., Ed., "Protocol Extensions for Support of Diffserv-aware MPLS Traffic Engineering", RFC 4124, June 2005.June 2005[RFC4506]RFC 4506Eisler, M., Ed., "XDR: External Data Representation Standard", STD 67, RFC 4506, May 2006.May 2006[RFC6004]RFC 6004Berger, L. and D. Fedyk, "Generalized MPLS (GMPLS) Support for Metro Ethernet Forum and G.8011 Ethernet Services", RFC 6004, October 2010.October 2010
[MEF10.1]The MEF Technical Specification, "Ethernet Services Attributes Phase 2", MEF 10.1, November 2006.