draft-ietf-isis-mpls-elc-11.txt   draft-ietf-isis-mpls-elc-12.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: September 25, 2020 Expires: October 30, 2020
P. Psenak P. Psenak
C. Filsfils C. Filsfils
S. Litkowski S. Litkowski
Cisco Systems, Inc. Cisco Systems, Inc.
M. Bocci M. Bocci
Nokia Nokia
March 24, 2020 April 28, 2020
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-11 draft-ietf-isis-mpls-elc-12
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 Label Switched Path (LSP) unless an egress LSR has indicated given Label Switched Path (LSP) unless an egress LSR has indicated
via signaling that it has the capability to process ELs, referred to via signaling that it has the capability to process ELs, referred to
as the Entropy Label Capability (ELC), on that tunnel. In addition, as the Entropy Label Capability (ELC), on that tunnel. In addition,
it would be useful for ingress LSRs to know each LSR's capability for it would be useful for ingress LSRs to know each LSR's capability for
skipping to change at page 1, line 48 skipping to change at page 1, line 48
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 25, 2020. This Internet-Draft will expire on October 30, 2020.
Copyright Notice Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 2, line 34 skipping to change at page 2, line 34
3. Advertising ELC Using IS-IS . . . . . . . . . . . . . . . . . 3 3. Advertising ELC Using IS-IS . . . . . . . . . . . . . . . . . 3
4. Advertising ERLD Using IS-IS . . . . . . . . . . . . . . . . 4 4. Advertising ERLD Using IS-IS . . . . . . . . . . . . . . . . 4
5. Signaling ELC and ERLD in BGP-LS . . . . . . . . . . . . . . 4 5. Signaling ELC and ERLD in BGP-LS . . . . . . . . . . . . . . 4
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
7. Security Considerations . . . . . . . . . . . . . . . . . . . 5 7. Security Considerations . . . . . . . . . . . . . . . . . . . 5
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 5 8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 5
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
10.1. Normative References . . . . . . . . . . . . . . . . . . 6 10.1. Normative References . . . . . . . . . . . . . . . . . . 6
10.2. Informative References . . . . . . . . . . . . . . . . . 7 10.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
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). It also Switching (MPLS) traffic flows using Entropy Labels (EL). It also
introduces the concept of Entropy Label Capability (ELC) and defines introduces the concept of Entropy Label Capability (ELC) and defines
the signaling of this capability via MPLS signaling protocols. the signaling of this capability via MPLS signaling protocols.
Recently, mechanisms have been defined to signal labels via link- Recently, mechanisms have been defined to signal labels via link-
state Interior Gateway Protocols (IGP) such as IS-IS [RFC8660]. This state Interior Gateway Protocols (IGP) such as IS-IS [RFC8667]. This
draft defines a mechanism to signal the ELC using IS-IS. draft defines a mechanism to signal the ELC using IS-IS.
In cases where LSPs are used for whatever reasons (e.g., SR-MPLS In cases where LSPs are used (e.g., SR-MPLS [RFC8660], it would be
[RFC8660], it would be useful for ingress LSRs to know each useful for ingress LSRs to know each intermediate LSR's capability of
intermediate LSR's capability of reading the maximum label stack reading the maximum label stack depth and performing EL-based load-
depth and performing EL-based load-balancing. This capability, balancing. This capability, referred to as Entropy Readable Label
referred to as Entropy Readable Label Depth (ERLD) as defined in Depth (ERLD) as defined in [RFC8662] may be used by ingress LSRs to
[RFC8662] may be used by ingress LSRs to determine the position of determine the position of the EL label in the stack, and whether it's
the EL label in the stack, and whether it's necessary to insert necessary to insert multiple ELs at different positions in the label
multiple ELs at different positions in the label stack. stack.
2. Terminology 2. Terminology
This memo makes use of the terms defined in [RFC6790], and [RFC8662]. This memo makes use of the terms defined in [RFC6790], and [RFC8662].
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
skipping to change at page 3, line 27 skipping to change at page 3, line 27
3. Advertising ELC Using IS-IS 3. Advertising ELC Using IS-IS
Even though ELC is a property of the node, in some cases it is Even though ELC is a property of the node, in some cases it is
advantageous to associate and advertise the ELC with a prefix. In a advantageous to associate and advertise the ELC with a prefix. In a
multi-area network, routers may not know the identity of the prefix multi-area network, routers may not know the identity of the prefix
originator in a remote area, or may not know the capabilities of such originator in a remote area, or may not know the capabilities of such
originator. Similarly in a multi-domain network, the identity of the originator. Similarly in a multi-domain network, the identity of the
prefix originator and its capabilities may not be known to the prefix originator and its capabilities may not be known to the
ingress LSR. ingress LSR.
Bit 3 in the Prefix Attribute Flags [RFC7794] is used as the ECL Flag Bit 3 in the Prefix Attribute Flags [RFC7794] is used as the ELC Flag
(E-flag), as shown in Figure 1. If a router has multiple interfaces, (E-flag), as shown in Figure 1. If a router has multiple interfaces,
the router MUST NOT announce the ELC for any local host prefixes the router MUST NOT announce the ELC for any local host prefixes
unless all of its interfaces are capable of processing ELs. If a unless all of its interfaces are capable of processing ELs. If a
router supports ELs on all of its interfaces, it SHOULD set the ELC router supports ELs on all of its interfaces, it SHOULD set the ELC
for every local host prefix it advertises in IS-IS. for every local host prefix it advertises in IS-IS.
0 1 2 3 4 5 6 7... 0 1 2 3 4 5 6 7...
+-+-+-+-+-+-+-+-+... +-+-+-+-+-+-+-+-+...
|X|R|N|E| ... |X|R|N|E| ...
+-+-+-+-+-+-+-+-+... +-+-+-+-+-+-+-+-+...
skipping to change at page 4, line 9 skipping to change at page 4, line 9
redistributing from another protocol to an IS-IS protocol instance, a redistributing from another protocol to an IS-IS protocol instance, a
router SHOULD preserve the ELC signaling for that prefix. The exact router SHOULD preserve the ELC signaling for that prefix. The exact
mechanism used to exchange ELC between protocol instances running on mechanism used to exchange ELC between protocol instances running on
an Autonomous System Boundary Router (ASBR) is outside of the scope an Autonomous System Boundary Router (ASBR) is outside of the scope
of this document. of this document.
4. Advertising ERLD Using IS-IS 4. Advertising ERLD Using IS-IS
A new MSD-type [RFC8491], called ERLD-MSD is defined to advertise the A new MSD-type [RFC8491], called ERLD-MSD is defined to advertise the
ERLD [RFC8662] of a given router. A MSD-Type code 2 has been ERLD [RFC8662] of a given router. A MSD-Type code 2 has been
assigned by IANA for EARLD-MSD. MSD-Value field is set to the ERLD assigned by IANA for ERLD-MSD. The MSD-Value field is set to the
in the range between 0 to 255. The scope of the advertisement ERLD in the range between 0 to 255. The scope of the advertisement
depends on the application. If a router has multiple interfaces with depends on the application. If a router has multiple interfaces with
different capabilities of reading the maximum label stack depth, the different capabilities of reading the maximum label stack depth, the
router MUST advertise the smallest one. router MUST advertise the smallest one.
The absence of ERLD-MSD advertisements indicates only that the The absence of ERLD-MSD advertisements indicates only that the
advertising node does not support advertisement of this capability. advertising node does not support advertisement of this capability.
The considerations for advertising the ERLD are specified in The considerations for advertising the ERLD are specified in
[RFC8662]. [RFC8662].
skipping to change at page 4, line 40 skipping to change at page 4, line 40
5. Signaling ELC and ERLD in BGP-LS 5. Signaling ELC and ERLD in BGP-LS
The IS-IS extensions defined in this document can be advertised via The IS-IS extensions defined in this document can be advertised via
BGP-LS [RFC7752] using existing BGP-LS TLVs. BGP-LS [RFC7752] using existing BGP-LS TLVs.
The ELC is advertised using the Prefix Attribute Flags TLV as defined The ELC is advertised using the Prefix Attribute Flags TLV as defined
in [I-D.ietf-idr-bgp-ls-segment-routing-ext]. in [I-D.ietf-idr-bgp-ls-segment-routing-ext].
The ERLD-MSD is advertised using the Node MSD TLV as defined in The ERLD-MSD is advertised using the Node MSD TLV as defined in
[I-D.ietf-idr-bgp-ls-segment-routing-ext]. [I-D.ietf-idr-bgp-ls-segment-routing-msd].
6. IANA Considerations 6. IANA Considerations
Early allocation has been done by IANA for this document as follows: Early allocation has been done by IANA for this document as follows:
- Bit 3 in the Bit Values for Prefix Attribute Flags Sub-TLV - Bit 3 in the Bit Values for Prefix Attribute Flags Sub-TLV
registry has been assigned to the ELC Flag. IANA is asked to registry has been assigned to the ELC Flag. IANA is asked to
update the registry to reflect the name used in this document: ECL update the registry to reflect the name used in this document: ELC
Flag (E-flag). Flag (E-flag).
- Type 2 in the IGP MSD-Types registry has been assigned for the - Type 2 in the IGP MSD-Types registry has been assigned for the
ERLD-MSD. IANA is asked to update the registry to reflect the ERLD-MSD. IANA is asked to update the registry to reflect the
name used in this document: ERLD-MSD. name used in this document: ERLD-MSD.
7. Security Considerations 7. Security Considerations
This document specifies the ability to advertise additional node This document specifies the ability to advertise additional node
capabilities using IS-IS and BGP-LS. As such, the security capabilities using IS-IS and BGP-LS. As such, the security
considerations as described in [RFC4971], [RFC7752], [RFC7794], considerations as described in [RFC7981], [RFC7752], [RFC7794],
[RFC8491], [RFC7752], [RFC8662], [RFC8491], [RFC8662], [I-D.ietf-idr-bgp-ls-segment-routing-ext] and
[I-D.ietf-idr-bgp-ls-segment-routing-ext] and
[I-D.ietf-idr-bgp-ls-segment-routing-msd] are applicable to this [I-D.ietf-idr-bgp-ls-segment-routing-msd] are applicable to this
document. document.
Incorrectly setting the E flag during origination, propagation or Incorrectly setting the E flag during origination, propagation or
redistribution may lead to black-holing of the traffic on the egress redistribution may lead to black-holing of the traffic on the egress
node. node.
Incorrectly setting of the ERLD value may lead to poor or no load- Incorrectly setting of the ERLD value may lead to poor or no load-
balancing of the traffic. balancing of the traffic.
skipping to change at page 6, line 26 skipping to change at page 6, line 26
[I-D.ietf-idr-bgp-ls-segment-routing-ext] [I-D.ietf-idr-bgp-ls-segment-routing-ext]
Previdi, S., Talaulikar, K., Filsfils, C., Gredler, H., Previdi, S., Talaulikar, K., Filsfils, C., Gredler, H.,
and M. Chen, "BGP Link-State extensions for Segment and M. Chen, "BGP Link-State extensions for Segment
Routing", draft-ietf-idr-bgp-ls-segment-routing-ext-16 Routing", draft-ietf-idr-bgp-ls-segment-routing-ext-16
(work in progress), June 2019. (work in progress), June 2019.
[I-D.ietf-idr-bgp-ls-segment-routing-msd] [I-D.ietf-idr-bgp-ls-segment-routing-msd]
Tantsura, J., Chunduri, U., Talaulikar, K., Mirsky, G., Tantsura, J., Chunduri, U., Talaulikar, K., Mirsky, G.,
and N. Triantafillis, "Signaling MSD (Maximum SID Depth) and N. Triantafillis, "Signaling MSD (Maximum SID Depth)
using Border Gateway Protocol - Link State", draft-ietf- using Border Gateway Protocol - Link State", draft-ietf-
idr-bgp-ls-segment-routing-msd-15 (work in progress), idr-bgp-ls-segment-routing-msd-17 (work in progress),
March 2020. April 2020.
[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,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC4971] Vasseur, JP., Ed., Shen, N., Ed., and R. Aggarwal, Ed.,
"Intermediate System to Intermediate System (IS-IS)
Extensions for Advertising Router Information", RFC 4971,
DOI 10.17487/RFC4971, July 2007,
<https://www.rfc-editor.org/info/rfc4971>.
[RFC5302] Li, T., Smit, H., and T. Przygienda, "Domain-Wide Prefix [RFC5302] Li, T., Smit, H., and T. Przygienda, "Domain-Wide Prefix
Distribution with Two-Level IS-IS", RFC 5302, Distribution with Two-Level IS-IS", RFC 5302,
DOI 10.17487/RFC5302, October 2008, DOI 10.17487/RFC5302, October 2008,
<https://www.rfc-editor.org/info/rfc5302>. <https://www.rfc-editor.org/info/rfc5302>.
[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>.
 End of changes. 14 change blocks. 
30 lines changed or deleted 23 lines changed or added

This html diff was produced by rfcdiff 1.47. The latest version is available from http://tools.ietf.org/tools/rfcdiff/