draft-ietf-isis-mpls-elc-04.txt   draft-ietf-isis-mpls-elc-05.txt 
Network Working Group X. Xu Network Working Group X. Xu
Internet-Draft Alibaba Inc Internet-Draft Alibaba Inc
Intended status: Standards Track S. Kini Intended status: Standards Track S. Kini
Expires: January 26, 2019 Expires: January 30, 2019
S. Sivabalan S. Sivabalan
C. Filsfils C. Filsfils
Cisco Cisco
S. Litkowski S. Litkowski
Orange Orange
July 25, 2018 July 29, 2018
Signaling Entropy Label Capability and Entropy Readable Label Depth Signaling Entropy Label Capability and Entropy Readable Label Depth
Using IS-IS Using IS-IS
draft-ietf-isis-mpls-elc-04 draft-ietf-isis-mpls-elc-05
Abstract Abstract
Multiprotocol Label Switching (MPLS) has defined a mechanism to load Multiprotocol Label Switching (MPLS) has defined a mechanism to load
balance traffic flows using Entropy Labels (EL). An ingress Label balance traffic flows using Entropy Labels (EL). An ingress Label
Switching Router (LSR) cannot insert ELs for packets going into a Switching Router (LSR) cannot insert ELs for packets going into a
given tunnel unless an egress LSR has indicated via signaling that it given tunnel unless an egress LSR has indicated via signaling that it
has the capability of processing ELs, referred to as Entropy Label has the capability of processing ELs, referred to as Entropy Label
Capability (ELC), on that tunnel. In addition, it would be useful Capability (ELC), on that tunnel. In addition, it would be useful
for ingress LSRs to know each LSR's capability of reading the maximum for ingress LSRs to know each LSR's capability of reading the maximum
label stack depth and performing EL-based load-balancing, referred to label stack depth and performing EL-based load-balancing, referred to
as Entropy Readable Label Depth (ERLD), in the cases where stacked as Entropy Readable Label Depth (ERLD), in the cases where stacked
LSPs are used for whatever reasons. This document defines mechanisms LSPs are used for whatever reasons. This document defines mechanisms
to signal these two capabilities using IS-IS. These mechanisms are to signal these two capabilities using IS-IS. These mechanisms are
useful when the label advertisement is also done via IS-IS. useful when the label advertisement is also done via IS-IS. In
addition, this document introduces the Non-IGP Functional
Capabilities Sub-TLV for advertising IS-IS router's actual non-IGP
functional capabilities. ELC is one of such non-IGP functional
capabilities.
Status of This Memo Status of This Memo
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Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Advertising ELC Using IS-IS . . . . . . . . . . . . . . . . . 3 3. Non-IGP Functional Capabilities Sub-TLV . . . . . . . . . . . 3
4. Advertising ERLD Using IS-IS . . . . . . . . . . . . . . . . 3 4. Advertising ELC Using IS-IS . . . . . . . . . . . . . . . . . 4
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 5. Advertising ERLD Using IS-IS . . . . . . . . . . . . . . . . 4
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
7. Security Considerations . . . . . . . . . . . . . . . . . . . 4 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 8. Security Considerations . . . . . . . . . . . . . . . . . . . 5
8.1. Normative References . . . . . . . . . . . . . . . . . . 4 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
8.2. Informative References . . . . . . . . . . . . . . . . . 5 9.1. Normative References . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 9.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction 1. Introduction
[RFC6790] describes a method to load balance Multiprotocol Label [RFC6790] describes a method to load balance Multiprotocol Label
Switching (MPLS) traffic flows using Entropy Labels (EL). [RFC6790] Switching (MPLS) traffic flows using Entropy Labels (EL). [RFC6790]
introduces the concept of Entropy Label Capability (ELC) and defines introduces the concept of Entropy Label Capability (ELC) and defines
the signalings of this capability via MPLS signaling protocols. the signalings of this capability via MPLS signaling protocols.
Recently, mechanisms are being defined to signal labels via link- Recently, mechanisms are being defined to signal labels via link-
state Interior Gateway Protocols (IGP) such as IS-IS state Interior Gateway Protocols (IGP) such as IS-IS
[I-D.ietf-isis-segment-routing-extensions]. In such scenario, the [I-D.ietf-isis-segment-routing-extensions]. In such scenario, the
skipping to change at page 3, line 18 skipping to change at page 3, line 24
least one EL in the label stack [I-D.ietf-mpls-spring-entropy-label]. least one EL in the label stack [I-D.ietf-mpls-spring-entropy-label].
2. Terminology 2. Terminology
This memo makes use of the terms defined in [RFC6790] and [RFC4971]. This memo makes use of the terms defined in [RFC6790] and [RFC4971].
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
3. Advertising ELC Using IS-IS 3. Non-IGP Functional Capabilities Sub-TLV
The IS-IS Router CAPABILITY TLV as defined in [RFC4971] is used by This document defines the Non-IGP Functional Capabilities Sub-TLV
IS-IS routers to announce their capabilities. A new sub-TLV of this with Sub-TLV type of TBD1 within the body of the IS-IS Router
TLV, called ELC sub-TLV is defined to advertise the capability of the Capability TLV. An IS-IS router advertising an IS-IS Router
router to process the ELs. As shown in Figure 1, it is formatted as Capability TLV MAY include the Non-IGP Functional Capabilities Sub-
described in [RFC5305] with a Type code to be assigned by IANA and a TLV. The Sub-TLV MUST reflect the advertising IS-IS router's actual
Length of zero. The scope of the advertisement depends on the non-IGP functional capabilities in the flooding scope of the
application. If a router has multiple linecards, the router MUST NOT containing Router Capability TLV.
advertise the ELC unless all of the linecards are capable of
processing ELs.
0 1 2 3 The format of the Router Non-IGP Functional Capabilities Sub-TLV is
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 as follows:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=TBD1 | Length=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: ELC sub-TLV Format
4. Advertising ERLD Using IS-IS 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=TBD1 | Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Non-IGP Functional Capabilities |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Non-IGP Functional Capabilities Sub-TLV Format
A new MSD-type of the IS-IS Node MSD sub-TLV Type: TBD1.
Length: Indicates the length of the value portion in octets and
will be a multiple of 4 octets dependent on the number of
capabilities advertised. Initially, the length will be 4,
denoting 4 octets of non-IGP functional capability bits.
Value: A variable-length sequence of capability bits rounded to a
multiple of 4 octets padded with undefined bits. Initially, there
are 4 octets of capability bits. Bits are numbered left to right
starting with the most significant bit being bit 0.
The Non-IGP Functional Capabilities Sub-TLV MAY be followed by
optional Sub-TLVs that further specify a non-IGP functional
capability. The specifications for non-IGP functional capabilities
advertised in this Sub-TLV MUST describe protocol behavior and
address backwards compatibility.
4. Advertising ELC Using IS-IS
One bit of the Non-IGP Functional Capability Bits (Bit 0 is desired)
is to be assigned by the IANA for the ELC [RFC6790]. If a router has
multiple line cards, the router MUST NOT announce the ELC [RFC6790]
unless all of its linecards are capable of processing ELs.
5. Advertising ERLD Using IS-IS
A new MSD-type of the Node MSD sub-TLV
[I-D.ietf-isis-segment-routing-msd], called ERLD is defined to [I-D.ietf-isis-segment-routing-msd], called ERLD is defined to
advertise the ERLD of a given router . As shown in Figure 2, it is advertise the ERLD of a given router. As shown in Figure 2, it is
formatted as described in [I-D.ietf-isis-segment-routing-msd] with a formatted as described in [I-D.ietf-isis-segment-routing-msd] with a
new MSD-Type code to be assigned by IANA (the type code of 2 is new MSD-Type code to be assigned by IANA (the type code of 2 is
desired) and the Value field is set to the ERLD in the range between desired) and the Value field is set to the ERLD in the range between
0 to 255. The scope of the advertisement depends on the application. 0 to 255. The scope of the advertisement depends on the application.
If a router has multiple linecards with different capabilities of If a router has multiple linecards with different capabilities of
reading the maximum label stack deepth, the router MUST advertise the reading the maximum label stack deepth, the router MUST advertise the
smallest one. smallest one.
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MSD-Type=TBD2 | ERLD | | MSD-Type=TBD2 | ERLD |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: ERLD MSD-Type Format Figure 2: ERLD MSD-Type Format
5. Acknowledgements 6. Acknowledgements
The authors would like to thank Yimin Shen, George Swallow, Acee The authors would like to thank Yimin Shen, George Swallow, Acee
Lindem, Les Ginsberg, Ketan Talaulikar, Jeff Tantsura and Carlos Lindem, Les Ginsberg, Ketan Talaulikar, Jeff Tantsura and Carlos
Pignataro for their valuable comments. Pignataro for their valuable comments.
6. IANA Considerations 7. IANA Considerations
IANA is requested to allocate one sub-TLV type of the IS-IS Router This document requests IANA to allocate one sub-TLV type of the
Capability TLV for ELC and a MSD type (the type code of 2 is desired) Router Capability TLV registry for the Non-IGP Functional
from the "IGP MSD Types" registry for ERLD. Capabilities Sub-TLV. Futhermore, this document requests IANA to
creat a subregistry for "Non-IGP Functional Capability Bits" within
the "Interior Gateway Protocol (IGP) Parameters" registry. This
subregistry is comprised of the fields Bit Number, Capability Name,
and Reference. Initially, one bit is reqested to be assigned for the
ELC. The registration procedure is "Expert Review" as defined in
[RFC8126]. The following values are defined by this document:
7. Security Considerations Bit No. Capability Name Reference
----- --------------------- -------------
0 ELC This document
1-31 Unassigned This document
Figure 3: Non-IGP Functional Capability Bits Registry
IANA is requested to allocate a MSD type (the type code of 2 is
desired) from the "IGP MSD Types" registry for ERLD.
8. Security Considerations
The security considerations as described in [RFC4971] is applicable The security considerations as described in [RFC4971] is applicable
to this document. This document does not introduce any new security to this document. This document does not introduce any new security
risk. risk.
8. References 9. References
8.1. Normative References 9.1. Normative References
[I-D.ietf-isis-segment-routing-extensions] [I-D.ietf-isis-segment-routing-extensions]
Previdi, S., Ginsberg, L., Filsfils, C., Bashandy, A., Previdi, S., Ginsberg, L., Filsfils, C., Bashandy, A.,
Gredler, H., Litkowski, S., Decraene, B., and J. Tantsura, Gredler, H., Litkowski, S., Decraene, B., and J. Tantsura,
"IS-IS Extensions for Segment Routing", draft-ietf-isis- "IS-IS Extensions for Segment Routing", draft-ietf-isis-
segment-routing-extensions-19 (work in progress), July segment-routing-extensions-19 (work in progress), July
2018. 2018.
[I-D.ietf-isis-segment-routing-msd] [I-D.ietf-isis-segment-routing-msd]
Tantsura, J., Chunduri, U., Aldrin, S., and L. Ginsberg, Tantsura, J., Chunduri, U., Aldrin, S., and L. Ginsberg,
skipping to change at page 5, line 25 skipping to change at page 6, line 31
[RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic
Engineering", RFC 5305, DOI 10.17487/RFC5305, October Engineering", RFC 5305, DOI 10.17487/RFC5305, October
2008, <https://www.rfc-editor.org/info/rfc5305>. 2008, <https://www.rfc-editor.org/info/rfc5305>.
[RFC6790] Kompella, K., Drake, J., Amante, S., Henderickx, W., and [RFC6790] Kompella, K., Drake, J., Amante, S., Henderickx, W., and
L. Yong, "The Use of Entropy Labels in MPLS Forwarding", L. Yong, "The Use of Entropy Labels in MPLS Forwarding",
RFC 6790, DOI 10.17487/RFC6790, November 2012, RFC 6790, DOI 10.17487/RFC6790, November 2012,
<https://www.rfc-editor.org/info/rfc6790>. <https://www.rfc-editor.org/info/rfc6790>.
8.2. Informative References [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
9.2. Informative References
[I-D.ietf-mpls-spring-entropy-label] [I-D.ietf-mpls-spring-entropy-label]
Kini, S., Kompella, K., Sivabalan, S., Litkowski, S., Kini, S., Kompella, K., Sivabalan, S., Litkowski, S.,
Shakir, R., and J. Tantsura, "Entropy label for SPRING Shakir, R., and J. Tantsura, "Entropy label for SPRING
tunnels", draft-ietf-mpls-spring-entropy-label-12 (work in tunnels", draft-ietf-mpls-spring-entropy-label-12 (work in
progress), July 2018. progress), July 2018.
Authors' Addresses Authors' Addresses
Xiaohu Xu Xiaohu Xu
Alibaba Inc Alibaba Inc
Email: xiaohu.xxh@alibabab-inc.com Email: xiaohu.xxh@alibaba-inc.com
Sriganesh Kini Sriganesh Kini
Email: sriganeshkini@gmail.com Email: sriganeshkini@gmail.com
Siva Sivabalan Siva Sivabalan
Cisco Cisco
Email: msiva@cisco.com Email: msiva@cisco.com
Clarence Filsfils Clarence Filsfils
Cisco Cisco
Email: cfilsfil@cisco.com Email: cfilsfil@cisco.com
Stephane Litkowski Stephane Litkowski
Orange Orange
Email: stephane.litkowski@orange.com Email: stephane.litkowski@orange.com
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