< draft-ietf-isis-mpls-elc-02.txt   draft-ietf-isis-mpls-elc-03.txt >
ISIS Working Group X. Xu ISIS Working Group X. Xu
Internet-Draft Huawei Internet-Draft Huawei
Intended status: Standards Track S. Kini Intended status: Standards Track S. Kini
Expires: April 17, 2017 Ericsson Expires: July 7, 2018 Ericsson
S. Sivabalan S. Sivabalan
C. Filsfils C. Filsfils
Cisco Cisco
S. Litkowski S. Litkowski
Orange Orange
October 14, 2016 January 3, 2018
Signaling Entropy Label Capability Using IS-IS Signaling Entropy Label Capability and Readable Label-stack Depth Using
draft-ietf-isis-mpls-elc-02 IS-IS
draft-ietf-isis-mpls-elc-03
Abstract Abstract
Multi Protocol 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 LSR balance traffic flows using Entropy Labels (EL). An ingress Label
cannot insert ELs for packets going into a given tunnel unless an Switching Router (LSR) cannot insert ELs for packets going into a
egress LSR has indicated via signaling that it can process ELs on given tunnel unless an egress LSR has indicated via signaling that it
that tunnel. This draft defines a mechanism to signal that has the capability of processing ELs, referred to as Entropy Label
capability using IS-IS. This mechanism is useful when the label Capability (ELC), on that tunnel. In addition, it would be useful
advertisement is also done via IS-IS. for ingress LSRs to know each LSR's capability of reading the maximum
label stack depth, referred to as Readable Label-stack Depth (RLD),
in the cases where stacked LSPs are used for whatever reasons. This
document defines mechanisms to signal these two capabilities using
OSPF. These mechanisms are useful when the label advertisement is
also done via IS-IS.
Requirements Language Requirements Language
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].
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on April 17, 2017. This Internet-Draft will expire on July 7, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2016 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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described in the Simplified BSD License. described in the Simplified BSD License.
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. Advertising ELC Using IS-IS . . . . . . . . . . . . . . . . . 3
4. Advertising RLDC Using IS-IS . . . . . . . . . . . . . . . . 3 4. Advertising RLD Using IS-IS . . . . . . . . . . . . . . . . . 3
5. Usage and Applicability . . . . . . . . . . . . . . . . . . . 4 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 7. Security Considerations . . . . . . . . . . . . . . . . . . . 4
8. Security Considerations . . . . . . . . . . . . . . . . . . . 4 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 8.1. Normative References . . . . . . . . . . . . . . . . . . 4
9.1. Normative References . . . . . . . . . . . . . . . . . . 4 8.2. Informative References . . . . . . . . . . . . . . . . . 4
9.2. Informative References . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction 1. Introduction
Multi Protocol Label Switching (MPLS) has defined a method in [RFC6790] describes a method to load balance Multiprotocol Label
[RFC6790] to load balance traffic flows using Entropy Labels (EL). Switching (MPLS) traffic flows using Entropy Labels (EL). [RFC6790]
An ingress LSR cannot insert ELs for packets going into a given introduces the concept of Entropy Label Capability (ELC) and defines
tunnel unless an egress LSR has indicated that it can process ELs on the signalings of this capability via MPLS signaling protocols.
that tunnel. [RFC6790] defines the signaling of this capability Recently, mechanisms are being defined to signal labels via link-
(a.k.a., Entropy Label Capability - ELC) via signaling protocols.
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
signaling mechanisms defined in [RFC6790] are inadequate. This draft signaling mechanisms defined in [RFC6790] are inadequate. This draft
defines a mechanism to signal the ELC using IS-IS. This mechanism is defines a mechanism to signal the ELC [RFC6790] using IS-IS. This
useful when the label advertisement is also done via IS-IS. In mechanism is useful when the label advertisement is also done via IS-
addition, in the cases where stacked LSPs are used for whatever IS. In addition, in the cases where stacked LSPs are used for
reasons (e.g., SPRING-MPLS [I-D.ietf-spring-segment-routing-mpls]), whatever reasons (e.g., SPRING-MPLS
it would be useful for ingress LSRs to know each LSR's capability of [I-D.ietf-spring-segment-routing-mpls]), it would be useful for
reading the maximum label stack deepth. This capability, referred to ingress LSRs to know each LSR's capability of reading the maximum
as Readable Label Deepth Capability (RLDC) can be used by ingress label stack depth. This capability, referred to as Readable Label-
LSRs to determine whether it's necessary to insert an EL for a given stack Depth (RLD) may be used by ingress LSRs to determine whether
LSP tunnel in the case where there has already been at least one EL it's necessary to insert an EL for a given LSP of the stacked LSP
in the label stack [I-D.ietf-mpls-spring-entropy-label] . Of course, tunnel in the case where there has already been at least one EL in
even it has been determined that it's neccessary to insert an EL for the label stack [I-D.ietf-mpls-spring-entropy-label].
a given LSP tunnel, if the egress LSR of that LSP tunnel has not yet
indicated that it can process ELs for that tunnel, the ingress LSR
MUST NOT include an entropy label for that tunnel as well.
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].
3. Advertising ELC Using IS-IS 3. Advertising ELC Using IS-IS
The IS-IS Router CAPABILITY TLV as defined in [RFC4971] is used by The IS-IS Router CAPABILITY TLV as defined in [RFC4971] is used by
IS-IS routers to announce their capabilities. A new sub-TLV of this IS-IS routers to announce their capabilities. A new sub-TLV of this
TLV, called ELC sub-TLV is defined to advertise the capability of the TLV, called ELC sub-TLV is defined to advertise the capability of the
router to process the ELs. It is formatted as described in [RFC5305] router to process the ELs. As shown in Figure 1, it is formatted as
with a Type code to be assigned by IANA and a Length of zero. The described in [RFC5305] with a Type code to be assigned by IANA and a
scope of the advertisement depends on the application but it is Length of zero. The scope of the advertisement depends on the
RECOMMENDED that it SHOULD be domain-wide. If a router has multiple application but it is RECOMMENDED that it SHOULD be domain-wide. If
linecards, the router MUST NOT advertise the ELC unless all of the a router has multiple linecards, the router MUST NOT advertise the
linecards are capable of processing ELs. ELC unless all of the linecards are capable of processing ELs.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=TBD1 | Length=0 | | Type=TBD1 | Length=0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: ELC sub-TLV Format Figure 1: ELC sub-TLV Format
4. Advertising RLDC Using IS-IS 4. Advertising RLD Using IS-IS
A new sub-TLV of the IS-IS Router CAPABILITY TLV, called RLDC sub-TLV A new sub-TLV of the IS-IS Router CAPABILITY TLV, called RLD sub-TLV
is defined to advertise the capability of the router to read the is defined to advertise the capability of the router to read the
maximum label stack depth. As shown in Figure 2, it is formatted as maximum label stack depth. As shown in Figure 2, it is formatted as
described in [RFC5305] with a Type code to be assigned by IANA and a described in [RFC5305] with a Type code to be assigned by IANA and a
Length of one. The Value field is set to the maximum readable label Length of one. The Value field is set to the maximum readable label
stack deepth in the range between 1 to 255. The scope of the stack deepth in the range between 1 to 255. The scope of the
advertisement depends on the application but it is RECOMMENDED that advertisement depends on the application but it is RECOMMENDED that
it SHOULD be domain-wide. If a router has multiple linecards with it SHOULD be domain-wide. If a router has multiple linecards with
different capabilities of reading the maximum label stack deepth, the different capabilities of reading the maximum label stack deepth, the
router MUST advertise the smallest one in the RLDC sub-TLV. router MUST advertise the smallest one in the RLDC sub-TLV.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=TBD2 | Length=1 | RLD | | Type=TBD2 | Length=1 | RLD |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: RLDC sub-TLV Format Figure 2: RLD sub-TLV Format
5. Usage and Applicability
The ELC is used by ingress LSRs to determine whether an EL could be
inserted into a given LSP tunnel. The RLDC is used by ingress LSRs
to determine whether it's necessary to insert an EL for a given LSP
tunnel in the case where there has already been at least one EL in
the label stack. This document only describes how to signal the ELC
and RLDC using IS-IS. As for how to apply those capabilities when
inserting EL(s) into LSP tunnel(s), it's outside the scope of this
document and accordingly would be described in
[I-D.ietf-mpls-spring-entropy-label].
6. Acknowledgements 5. Acknowledgements
The authors would like to thank Yimin Shen, George Swallow, Acee The authors would like to thank Yimin Shen, George Swallow, Acee
Lindem and Carlos Pignataro for their valuable comments. Lindem and Carlos Pignataro for their valuable comments.
7. IANA Considerations 6. IANA Considerations
This memo includes a request to IANA to allocate two sub-TLV types This memo includes a request to IANA to allocate two sub-TLV types
within the IS-IS Router Capability TLV. within the IS-IS Router Capability TLV.
8. Security Considerations 7. Security Considerations
The security considerations as described in [RFC4971] is appliable to The security considerations as described in [RFC4971] is applicable
this document. This document does not introduce any new security to this document. This document does not introduce any new security
risk. risk.
9. References 8. References
9.1. Normative References 8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC4971] Vasseur, JP., Ed., Shen, N., Ed., and R. Aggarwal, Ed., [RFC4971] Vasseur, JP., Ed., Shen, N., Ed., and R. Aggarwal, Ed.,
"Intermediate System to Intermediate System (IS-IS) "Intermediate System to Intermediate System (IS-IS)
Extensions for Advertising Router Information", RFC 4971, Extensions for Advertising Router Information", RFC 4971,
DOI 10.17487/RFC4971, July 2007, DOI 10.17487/RFC4971, July 2007,
<http://www.rfc-editor.org/info/rfc4971>. <https://www.rfc-editor.org/info/rfc4971>.
9.2. Informative References 8.2. Informative References
[I-D.ietf-isis-segment-routing-extensions] [I-D.ietf-isis-segment-routing-extensions]
Previdi, S., Filsfils, C., Bashandy, A., Gredler, H., Previdi, S., Ginsberg, L., Filsfils, C., Bashandy, A.,
Litkowski, S., Decraene, B., and j. jefftant@gmail.com, 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-08 (work in progress), October segment-routing-extensions-15 (work in progress), December
2016. 2017.
[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. jefftant@gmail.com, "Entropy labels for Shakir, R., and J. Tantsura, "Entropy label for SPRING
source routed tunnels with label stacks", draft-ietf-mpls- tunnels", draft-ietf-mpls-spring-entropy-label-07 (work in
spring-entropy-label-04 (work in progress), July 2016. progress), October 2017.
[I-D.ietf-spring-segment-routing-mpls] [I-D.ietf-spring-segment-routing-mpls]
Filsfils, C., Previdi, S., Bashandy, A., Decraene, B., Filsfils, C., Previdi, S., Bashandy, A., Decraene, B.,
Litkowski, S., Horneffer, M., Shakir, R., Litkowski, S., and R. Shakir, "Segment Routing with MPLS
jefftant@gmail.com, j., and E. Crabbe, "Segment Routing data plane", draft-ietf-spring-segment-routing-mpls-11
with MPLS data plane", draft-ietf-spring-segment-routing- (work in progress), October 2017.
mpls-05 (work in progress), July 2016.
[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, <http://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,
<http://www.rfc-editor.org/info/rfc6790>. <https://www.rfc-editor.org/info/rfc6790>.
Authors' Addresses Authors' Addresses
Xiaohu Xu Xiaohu Xu
Huawei Huawei
Email: xuxiaohu@huawei.com Email: xuxh.mail@gmail.com
Sriganesh Kini Sriganesh Kini
Ericsson Ericsson
Email: sriganesh.kini@ericsson.com Email: sriganesh.kini@ericsson.com
Siva Sivabalan Siva Sivabalan
Cisco Cisco
Email: msiva@cisco.com Email: msiva@cisco.com
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