draft-ietf-ospf-xaf-te-04.txt   draft-ietf-ospf-xaf-te-05.txt 
LSR A. Smirnov LSR A. Smirnov
Internet-Draft Cisco Systems, Inc. Internet-Draft Cisco Systems, Inc.
Updates: 5786 (if approved) A. Retana Updates: 5786 (if approved) A. Retana
Intended status: Standards Track Huawei R&D USA Intended status: Standards Track Huawei R&D USA
Expires: April 25, 2019 M. Barnes Expires: June 13, 2019 M. Barnes
Cisco Systems, Inc. Cisco Systems, Inc.
October 22, 2018 December 10, 2018
OSPF Routing with Cross-Address Family Traffic Engineering Tunnels OSPF Routing with Cross-Address Family Traffic Engineering Tunnels
draft-ietf-ospf-xaf-te-04 draft-ietf-ospf-xaf-te-05
Abstract Abstract
When using Traffic Engineering (TE) in a dual-stack IPv4/IPv6 When using Traffic Engineering (TE) in a dual-stack IPv4/IPv6
network, the Multiprotocol Label Switching (MPLS) TE Label Switched network, the Multiprotocol Label Switching (MPLS) TE Label Switched
Paths (LSP) infrastructure may be duplicated, even if the destination Paths (LSP) infrastructure may be duplicated, even if the destination
IPv4 and IPv6 addresses belong to the same remote router. In order IPv4 and IPv6 addresses belong to the same remote router. In order
to achieve an integrated MPLS TE LSP infrastructure, OSPF routes must to achieve an integrated MPLS TE LSP infrastructure, OSPF routes must
be computed over MPLS TE tunnels created using information propagated be computed over MPLS TE tunnels created using information propagated
in another OSPF instance. This issue is solved by advertising cross- in another OSPF instance. This issue is solved by advertising cross-
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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 April 25, 2019. This Internet-Draft will expire on June 13, 2019.
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.
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
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to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
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. Requirements Language . . . . . . . . . . . . . . . . . . . . 3 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3
3. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Backward Compatibility . . . . . . . . . . . . . . . . . . . 5 4. Backward Compatibility . . . . . . . . . . . . . . . . . . . 6
4.1. Automatically Switched Optical Networks . . . . . . . . . 6 4.1. Automatically Switched Optical Networks . . . . . . . . . 6
5. Security Considerations . . . . . . . . . . . . . . . . . . . 6 5. Security Considerations . . . . . . . . . . . . . . . . . . . 6
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
8.1. Normative References . . . . . . . . . . . . . . . . . . 7 8.1. Normative References . . . . . . . . . . . . . . . . . . 7
8.2. Informative References . . . . . . . . . . . . . . . . . 7 8.2. Informative References . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction 1. Introduction
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business characteristics and/or applications or class of service, not business characteristics and/or applications or class of service, not
constrained by the network protocol used. constrained by the network protocol used.
For example, an LSP created based on MPLS TE information propagated For example, an LSP created based on MPLS TE information propagated
by an OSPFv2 instance can be used to transport both IPv4 and IPv6 by an OSPFv2 instance can be used to transport both IPv4 and IPv6
traffic, as opposed to using both OSPFv2 and OSPFv3 to provision a traffic, as opposed to using both OSPFv2 and OSPFv3 to provision a
separate LSP for each address family. Even if in some cases the separate LSP for each address family. Even if in some cases the
address family-specific traffic is to be separated, calculation from address family-specific traffic is to be separated, calculation from
a common database may prove to be operationally beneficial. a common database may prove to be operationally beneficial.
A requirement when creating a common MPLS TE infrastructure is the During the SPF calculation on the TE tunnel head-end router, OSPF
ability to reliably map the X-AF family addresses to the computes shortcut routes using TE tunnels. A commonly used algorithm
corresponding advertising tail-end router. This mapping is a for computing shortcuts is defined in [RFC3906]. For that, or any
similar, algorithm to work with a common MPLS TE infrastructure in a
dual-stack network, a requirement is to reliably map the X-AF
addresses to the corresponding tail-end router. This mapping is a
challenge because the LSAs containing the routing information are challenge because the LSAs containing the routing information are
carried in one OSPF instance while the TE calculation may be done carried in one OSPF instance while the TE calculations may be done
using a TE database from a different instance. using a TE database from a different OSPF instance.
A simple solution to this problem is to rely on the Router ID to A simple solution to this problem is to rely on the Router ID to
identify a node in the corresponding OSPFv2 and OSPFv3 databases. identify a node in the corresponding OSPFv2 and OSPFv3 databases.
This solution would mandate both instances on the same router to be This solution would mandate both instances on the same router to be
configured with the same Router ID. However, relying on the configured with the same Router ID. However, relying on the
correctness of configuration puts additional burden and cost on the correctness of configuration puts additional burden and cost on the
operation of the network. The network becomes even more difficult to operation of the network. The network becomes even more difficult to
manage if OSPFv2 and OSPFv3 topologies do not match exactly, for manage if OSPFv2 and OSPFv3 topologies do not match exactly, for
example if area borders are chosen differently in the two protocols. example if area borders are chosen differently in the two protocols.
Also, if the routing processes do fall out of sync (e.g., having Also, if the routing processes do fall out of sync (e.g., having
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one or more local X-AF addresses using the corresponding Local one or more local X-AF addresses using the corresponding Local
Address sub-TLV. In other words, to implement the X-AF routing Address sub-TLV. In other words, to implement the X-AF routing
technique described in this document, OSPFv2 will advertise the Node technique described in this document, OSPFv2 will advertise the Node
IPv6 Local Address sub-TLV and OSPFv3 will advertise the Node IPv4 IPv6 Local Address sub-TLV and OSPFv3 will advertise the Node IPv4
Local Address sub-TLV, possibly in addition to advertising other IP Local Address sub-TLV, possibly in addition to advertising other IP
addresses as documented by [RFC5786]. addresses as documented by [RFC5786].
A node that implements X-AF routing SHOULD advertise, in the A node that implements X-AF routing SHOULD advertise, in the
corresponding Node Local Address sub-TLV, all X-AF IPv4 and IPv6 corresponding Node Local Address sub-TLV, all X-AF IPv4 and IPv6
addresses local to the router that can be used by Constrained SPF addresses local to the router that can be used by Constrained SPF
(CSPF) to calculate MPLS TE LSPs. In general, OSPF SHOULD advertise (CSPF) to calculate MPLS TE LSPs. OSPF MUST advertise the IP address
the IP address listed in the Router Address TLV [RFC3630] [RFC5329] listed in the Router Address TLV [RFC3630] [RFC5329] of the X-AF
of the X-AF instance maintaining the MPLS TE database, plus any instance maintaining the MPLS TE database, and SHOULD include
additional local addresses advertised by the X-AF OSPF instance in additional local addresses advertised by the X-AF OSPF instance in
its Node Local Address sub-TLVs. An implementation MAY advertise its Node Local Address sub-TLVs. An implementation MAY advertise
other local X-AF addresses. other local X-AF addresses.
If the Node Attribute TLV carries both the Node IPv4 Local Address If the Node Attribute TLV carries both the Node IPv4 Local Address
sub-TLV and the Node IPv6 Local Address sub-TLV, then the X-AF sub-TLV and the Node IPv6 Local Address sub-TLV, then the X-AF
component MUST be considered for the consolidated calculation of MPLS component MUST be considered for the consolidated calculation of MPLS
TE LSPs. Both instances MAY advertise the required information and TE LSPs. Both instances MAY advertise the required information and
it is left to local configuration to determine which database is it is left to local configuration to determine which database is
used. used.
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connected to the same set of areas to know with which area to connected to the same set of areas to know with which area to
associate computed MPLS TE tunnels. associate computed MPLS TE tunnels.
During the X-AF routing calculation, X-AF IP addresses are used to During the X-AF routing calculation, X-AF IP addresses are used to
map locally created LSPs to tail-end routers in the Link State map locally created LSPs to tail-end routers in the Link State
Database (LSDB). The mapping algorithm can be described as: Database (LSDB). The mapping algorithm can be described as:
Walk the list of all MPLS TE tunnels for which the computing Walk the list of all MPLS TE tunnels for which the computing
router is a head-end. For each MPLS TE tunnel T: router is a head-end. For each MPLS TE tunnel T:
1. If T's destination IP address is from the same address family as 1. If T's destination address is from the same address family as the
the computing OSPF instance, then the tunnel must have been OSPF instance associated with the LSDB, then the extensions
signaled based on MPLS TE information propagated in the same OSPF defined in this document do not apply.
instance. Process the tunnel as per [RFC3630] or [RFC5329].
2. Otherwise it is a X-AF MPLS TE tunnel. Note tunnel's destination 2. Otherwise it is a X-AF MPLS TE tunnel. Note tunnel's destination
IP address. IP address.
3. Walk the X-AF IP addresses in the LSDBs of all connected areas. 3. Walk the X-AF IP addresses in the LSDBs of all connected areas.
If a matching IP address is found, advertised by router R in area If a matching IP address is found, advertised by router R in area
A, then mark the tunnel T as belonging to area A and terminating A, then mark the tunnel T as belonging to area A and terminating
on tail-end router R. Assign the intra-area SPF cost to reach on tail-end router R. Assign the intra-area SPF cost to reach
router R within area A as the IGP cost of tunnel T. router R within area A as the IGP cost of tunnel T.
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[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328,
DOI 10.17487/RFC2328, April 1998, DOI 10.17487/RFC2328, April 1998,
<https://www.rfc-editor.org/info/rfc2328>. <https://www.rfc-editor.org/info/rfc2328>.
[RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
(TE) Extensions to OSPF Version 2", RFC 3630, (TE) Extensions to OSPF Version 2", RFC 3630,
DOI 10.17487/RFC3630, September 2003, DOI 10.17487/RFC3630, September 2003,
<https://www.rfc-editor.org/info/rfc3630>. <https://www.rfc-editor.org/info/rfc3630>.
[RFC3906] Shen, N. and H. Smit, "Calculating Interior Gateway
Protocol (IGP) Routes Over Traffic Engineering Tunnels",
RFC 3906, DOI 10.17487/RFC3906, October 2004,
<https://www.rfc-editor.org/info/rfc3906>.
[RFC4461] Yasukawa, S., Ed., "Signaling Requirements for Point-to- [RFC4461] Yasukawa, S., Ed., "Signaling Requirements for Point-to-
Multipoint Traffic-Engineered MPLS Label Switched Paths Multipoint Traffic-Engineered MPLS Label Switched Paths
(LSPs)", RFC 4461, DOI 10.17487/RFC4461, April 2006, (LSPs)", RFC 4461, DOI 10.17487/RFC4461, April 2006,
<https://www.rfc-editor.org/info/rfc4461>. <https://www.rfc-editor.org/info/rfc4461>.
[RFC5329] Ishiguro, K., Manral, V., Davey, A., and A. Lindem, Ed., [RFC5329] Ishiguro, K., Manral, V., Davey, A., and A. Lindem, Ed.,
"Traffic Engineering Extensions to OSPF Version 3", "Traffic Engineering Extensions to OSPF Version 3",
RFC 5329, DOI 10.17487/RFC5329, September 2008, RFC 5329, DOI 10.17487/RFC5329, September 2008,
<https://www.rfc-editor.org/info/rfc5329>. <https://www.rfc-editor.org/info/rfc5329>.
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