draft-ietf-bier-ospf-bier-extensions-10.txt   draft-ietf-bier-ospf-bier-extensions-11.txt 
OSPF P. Psenak, Ed. OSPF P. Psenak, Ed.
Internet-Draft N. Kumar Internet-Draft N. Kumar
Intended status: Standards Track IJ. Wijnands Intended status: Standards Track IJ. Wijnands
Expires: June 7, 2018 Cisco Expires: August 16, 2018 Cisco
A. Dolganow A. Dolganow
Nokia Nokia
T. Przygienda T. Przygienda
J. Zhang J. Zhang
Juniper Networks, Inc. Juniper Networks, Inc.
S. Aldrin S. Aldrin
Google, Inc. Google, Inc.
December 4, 2017 February 12, 2018
OSPF Extensions for BIER OSPF Extensions for BIER
draft-ietf-bier-ospf-bier-extensions-10.txt draft-ietf-bier-ospf-bier-extensions-11.txt
Abstract Abstract
Bit Index Explicit Replication (BIER) is an architecture that Bit Index Explicit Replication (BIER) is an architecture that
provides multicast forwarding through a "BIER domain" without provides multicast forwarding through a "BIER domain" without
requiring intermediate routers to maintain multicast related per-flow requiring intermediate routers to maintain multicast related per-flow
state. Neither does BIER require an explicit tree-building protocol state. Neither does BIER require an explicit tree-building protocol
for its operation. A multicast data packet enters a BIER domain at a for its operation. A multicast data packet enters a BIER domain at a
"Bit-Forwarding Ingress Router" (BFIR), and leaves the BIER domain at "Bit-Forwarding Ingress Router" (BFIR), and leaves the BIER domain at
one or more "Bit-Forwarding Egress Routers" (BFERs). The BFIR router one or more "Bit-Forwarding Egress Routers" (BFERs). The BFIR router
adds a BIER header to the packet. Such header contains a bit-string adds a BIER header to the packet. Such header contains a bit-string
in which each bit represents exactly one BFER to forward the packet in which each bit represents exactly one BFER to forward the packet
to. The set of BFERs to which the multicast packet needs to be to. The set of BFERs to which the multicast packet needs to be
forwarded is expressed by the according set of bits set in BIER forwarded is expressed by the according set of bits set in BIER
packet header. packet header.
This document describes the OSPF protocol extension required for BIER This document describes the OSPF [RFC2328] protocol extension
with MPLS encapsulation. required for BIER with MPLS encapsulation.
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
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 June 7, 2018. This Internet-Draft will expire on August 16, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2017 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
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
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
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contains a bit-string in which each bit represents exactly one BFER contains a bit-string in which each bit represents exactly one BFER
to forward the packet to. The set of BFERs to which the multicast to forward the packet to. The set of BFERs to which the multicast
packet needs to be forwarded is expressed by setting the bits that packet needs to be forwarded is expressed by setting the bits that
correspond to those routers in the BIER header. correspond to those routers in the BIER header.
BIER architecture requires routers participating in BIER to exchange BIER architecture requires routers participating in BIER to exchange
BIER related information within a given domain. BIER architecture BIER related information within a given domain. BIER architecture
permits link-state routing protocols to perform distribution of such permits link-state routing protocols to perform distribution of such
information. This document describes extensions to OSPF necessary to information. This document describes extensions to OSPF necessary to
advertise BIER specific information in the case where BIER uses MPLS advertise BIER specific information in the case where BIER uses MPLS
encapsulation as described in [I-D.ietf-bier-mpls-encapsulation]. encapsulation as described in [RFC8296].
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 [RFC2119]. document are to be interpreted as described in [RFC2119].
2. Flooding of the BIER Information in OSPF 2. Flooding of the BIER Information in OSPF
All BIER specific information that a Bit-Forwarding Router (BFR) All BIER specific information that a Bit-Forwarding Router (BFR)
needs to advertise to other BFRs is associated with a BFR-Prefix. A needs to advertise to other BFRs is associated with a BFR-Prefix. A
BFR prefix is a unique (within a given BIER domain) routable IP BFR prefix is a unique (within a given BIER domain) routable IP
address that is assigned to each BFR as described in more detail in address that is assigned to each BFR as described in more detail in
section 2 of [I-D.ietf-bier-architecture]. section 2 of [RFC8279].
Given that BIER information must be associated with a BFR prefix, the Given that BIER information must be associated with a BFR prefix, the
OSPF Extended Prefix Opaque LSA [RFC7684] has been chosen for OSPF Extended Prefix Opaque LSA [RFC7684] has been chosen for
advertisement. advertisement.
2.1. BIER Sub-TLV 2.1. BIER Sub-TLV
A Sub-TLV of the Extended Prefix TLV (defined in [RFC7684]) is A Sub-TLV of the Extended Prefix TLV (defined in [RFC7684]) is
defined for distributing BIER information. The Sub-TLV is called the defined for distributing BIER information. The Sub-TLV is called the
BIER Sub-TLV. Multiple BIER Sub-TLVs may be included in the Extended BIER Sub-TLV. Multiple BIER Sub-TLVs may be included in the Extended
skipping to change at page 4, line 7 skipping to change at page 4, line 7
| BAR | Reserved | | BAR | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub-TLVs (variable) | | Sub-TLVs (variable) |
+- -+ +- -+
| | | |
Type: 9 Type: 9
Length: Variable, dependent on sub-TLVs. Length: Variable, dependent on sub-TLVs.
Sub-domain-ID: Unique value identifying the BIER sub-domain within Sub-domain-ID: Unique value identifying the BIER sub-domain within
the BIER domain, as described in section 1 of the BIER domain, as described in section 1 of [RFC8279].
[I-D.ietf-bier-architecture].
MT-ID: Multi-Topology ID (as defined in [RFC4915]) that identifies MT-ID: Multi-Topology ID (as defined in [RFC4915]) that identifies
the topology that is associated with the BIER sub-domain. the topology that is associated with the BIER sub-domain.
BFR-id: A 2 octet field encoding the BFR-id, as documented in BFR-id: A 2 octet field encoding the BFR-id, as documented in
section 2 of [I-D.ietf-bier-architecture]. If the BFR is not section 2 of [RFC8279]. If the BFR is not locally configured with
locally configured with a valid BFR-id, the value of this field is a valid BFR-id, the value of this field is set to invalid BFR-id
set to invalid BFR-id per [I-D.ietf-bier-architecture]. per [RFC8279].
BAR: Single octet BIER Algorithm. 0 is the only supported value BAR: Single octet BIER Algorithm. 0 is the only supported value
defined in this document and represents Shortest Path First (SPF) defined in this document and represents Shortest Path First (SPF)
algorithm based on IGP link metric. This is the standard shortest algorithm based on IGP link metric. This is the standard shortest
path algorithm as computed by the OSPF protocol. Other values may path algorithm as computed by the OSPF protocol. Other values may
be defined in the future. be defined in the future.
Each BFR sub-domain MUST be associated with one and only one OSPF Each BFR sub-domain MUST be associated with one and only one OSPF
topology that is identified by the MT-ID. If the association between topology that is identified by the MT-ID. If the association between
BIER sub-domain and OSPF topology advertised in the BIER sub-TLV by BIER sub-domain and OSPF topology advertised in the BIER sub-TLV by
skipping to change at page 5, line 12 skipping to change at page 5, line 10
MPLS specific information used for BIER. It MAY appear multiple MPLS specific information used for BIER. It MAY appear multiple
times in the BIER Sub-TLV. times in the BIER Sub-TLV.
The BIER MPLS Encapsulation Sub-TLV has the following format: The BIER MPLS Encapsulation Sub-TLV has the following format:
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 | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Lbl Range Size | Label Range Base | | Max SI | Label |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|BS Len | Reserved | |BS Len | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: 10 Type: 10
Length: 4 octets Length: 4 octets
Label Range Size: A 1 octet field encoding the label range size of Max SI : A 1 octet field encoding the Maximum Set Identifier
the label range. It MUST be greater then 0, otherwise the (section 1 of [RFC8296]), used in the encapsulation for this BIER
advertising router MUST be treated as if it did not advertise a sub-domain for this bitstring length.
BIER sub-TLV.
Label Range Base: A 3 octet field, where the 20 rightmost bits Label: A 3 octet field, where the 20 rightmost bits represent the
represent the first label in the label range. The 4 leftmost bits first label in the label range. The 4 leftmost bits MUST be
MUST be ignored. ignored.
Bit String Length: A 4 bits field encoding the supported BitString Bit String Length: A 4 bits field encoding the supported BitString
length associated with this BFR-prefix. The values allowed in length associated with this BFR-prefix. The values allowed in
this field are specified in section 2 of this field are specified in section 2 of [RFC8296].
[I-D.ietf-bier-mpls-encapsulation].
The "label range" is the set of labels beginning with the label The "label range" is the set of labels beginning with the Label
range base and ending with ((label range base)+(label range size)- and ending with (Label + (Max SI)). A unique label range is
1). A unique label range is allocated for each BitStream length allocated for each BitStream length and Sub-domain-ID. These
and Sub-domain-ID. These labels are used for BIER forwarding as labels are used for BIER forwarding as described in [RFC8279] and
described in [I-D.ietf-bier-architecture] and [RFC8296].
[I-D.ietf-bier-mpls-encapsulation].
The size of the label range is determined by the number of Set The size of the label range is determined by the number of Set
Identifiers (SI) (section 1 of [I-D.ietf-bier-architecture]) that Identifiers (SI) (section 1 of [RFC8279]) that are used in the
are used in the network. Each SI maps to a single label in the network. Each SI maps to a single label in the label range. The
label range. The first label is for SI=0, the second label is for first label is for SI=0, the second label is for SI=1, etc.
SI=1, etc.
If same BS length is repeated in multiple BIER MPLS Encapsulation If same BS length is repeated in multiple BIER MPLS Encapsulation
Sub-TLV inside the same BIER Sub-TLV, the BIER sub-TLV MUST be Sub-TLV inside the same BIER Sub-TLV, the BIER sub-TLV MUST be
ignored. ignored.
Label ranges within all BIER MPLS Encapsulation Sub-TLV inside the Label ranges within all BIER MPLS Encapsulation Sub-TLV inside the
same BIER Sub-TLV MUST NOT overlap. If the overlap is detected, the same BIER Sub-TLV MUST NOT overlap. If the overlap is detected, the
advertising router MUST be treated as if it did not advertise a BIER advertising router MUST be treated as if it did not advertise a BIER
sub-TLV. sub-TLV.
skipping to change at page 6, line 49 skipping to change at page 6, line 41
- Examine its best path to the prefix in the source area and - Examine its best path to the prefix in the source area and
find the advertising router associated with the best path to find the advertising router associated with the best path to
that prefix. that prefix.
- Determine if such advertising router advertised a BIER Sub- - Determine if such advertising router advertised a BIER Sub-
TLV for the prefix. If yes, the ABR will copy the information TLV for the prefix. If yes, the ABR will copy the information
from such BIER Sub-TLV when advertising BIER Sub-TLV to each from such BIER Sub-TLV when advertising BIER Sub-TLV to each
attached area. attached area.
In the Figure 1, R1 advertises a prefix 192.0.0.1/32 in Area 1. In the Figure 1, R1 advertises a prefix 192.0.2.1/32 in Area 1.
It also advertises Extended Prefix Opaque LSA for prefix It also advertises Extended Prefix Opaque LSA for prefix
192.0.0.1/32 and includes BIER Sub-TLV in it. Area Border Router 192.0.2.1/32 and includes BIER Sub-TLV in it. Area Border Router
(ABR) R2 calculates the reachability for prefix 192.0.0.1/32 (ABR) R2 calculates the reachability for prefix 192.0.2.1/32
inside Area 1 and propagates it to Area 0. When doing so, it inside Area 1 and propagates it to Area 0. When doing so, it
copies the entire BIER Sub-TLV (including all its Sub-TLVs) it copies the entire BIER Sub-TLV (including all its Sub-TLVs) it
received from R1 in Area 1 and includes it in the Extended Prefix received from R1 in Area 1 and includes it in the Extended Prefix
Opaque LSA it generates for 192.0.0.1/32 in Area 0. ABR R3 Opaque LSA it generates for 192.0.2.1/32 in Area 0. ABR R3
calculates the reachability for prefix 192.0.0.1/32 inside Area 0 calculates the reachability for prefix 192.0.2.1/32 inside Area 0
and propagates it to Area 2. When doing so, it copies the entire and propagates it to Area 2. When doing so, it copies the entire
BIER Sub-TLV (including all its Sub-TLVs) it received from R2 in BIER Sub-TLV (including all its Sub-TLVs) it received from R2 in
Area 0 and includes it in the Extended Prefix Opaque LSA it Area 0 and includes it in the Extended Prefix Opaque LSA it
generates for 192.0.0.1/32 in Area 2. generates for 192.0.2.1/32 in Area 2.
3. Security Considerations 3. Security Considerations
Implementations must assure that malformed TLV and Sub-TLV Implementations must assure that malformed TLV and Sub-TLV
permutations do not result in errors which cause hard OSPF failures. permutations do not result in errors which cause hard OSPF failures.
4. IANA Considerations 4. IANA Considerations
The document requests three new allocations from the OSPF Extended The document requests three new allocations from the OSPF Extended
Prefix sub-TLV registry as defined in [RFC7684]. Prefix sub-TLV registry as defined in [RFC7684].
skipping to change at page 7, line 37 skipping to change at page 7, line 29
BIER MPLS Encapsulation Sub-TLV: 10 BIER MPLS Encapsulation Sub-TLV: 10
5. Acknowledgments 5. Acknowledgments
The authors would like to thank Rajiv Asati, Christian Martin, Greg The authors would like to thank Rajiv Asati, Christian Martin, Greg
Shepherd and Eric Rosen for their contribution. Shepherd and Eric Rosen for their contribution.
6. Normative References 6. Normative References
[I-D.ietf-bier-architecture]
Wijnands, I., Rosen, E., Dolganow, A., Przygienda, T., and
S. Aldrin, "Multicast using Bit Index Explicit
Replication", draft-ietf-bier-architecture-06 (work in
progress), April 2017.
[I-D.ietf-bier-mpls-encapsulation]
Wijnands, I., Rosen, E., Dolganow, A., Tantsura, J.,
Aldrin, S., and I. Meilik, "Encapsulation for Bit Index
Explicit Replication in MPLS and non-MPLS Networks",
draft-ietf-bier-mpls-encapsulation-07 (work in progress),
June 2017.
[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>.
[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328,
DOI 10.17487/RFC2328, April 1998,
<https://www.rfc-editor.org/info/rfc2328>.
[RFC4915] Psenak, P., Mirtorabi, S., Roy, A., Nguyen, L., and P. [RFC4915] Psenak, P., Mirtorabi, S., Roy, A., Nguyen, L., and P.
Pillay-Esnault, "Multi-Topology (MT) Routing in OSPF", Pillay-Esnault, "Multi-Topology (MT) Routing in OSPF",
RFC 4915, DOI 10.17487/RFC4915, June 2007, RFC 4915, DOI 10.17487/RFC4915, June 2007,
<https://www.rfc-editor.org/info/rfc4915>. <https://www.rfc-editor.org/info/rfc4915>.
[RFC7120] Cotton, M., "Early IANA Allocation of Standards Track Code
Points", BCP 100, RFC 7120, DOI 10.17487/RFC7120, January
2014, <https://www.rfc-editor.org/info/rfc7120>.
[RFC7684] Psenak, P., Gredler, H., Shakir, R., Henderickx, W., [RFC7684] Psenak, P., Gredler, H., Shakir, R., Henderickx, W.,
Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute
Advertisement", RFC 7684, DOI 10.17487/RFC7684, November Advertisement", RFC 7684, DOI 10.17487/RFC7684, November
2015, <https://www.rfc-editor.org/info/rfc7684>. 2015, <https://www.rfc-editor.org/info/rfc7684>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for [RFC8279] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
Writing an IANA Considerations Section in RFCs", BCP 26, Przygienda, T., and S. Aldrin, "Multicast Using Bit Index
RFC 8126, DOI 10.17487/RFC8126, June 2017, Explicit Replication (BIER)", RFC 8279,
<https://www.rfc-editor.org/info/rfc8126>. DOI 10.17487/RFC8279, November 2017,
<https://www.rfc-editor.org/info/rfc8279>.
[RFC8296] Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
Tantsura, J., Aldrin, S., and I. Meilik, "Encapsulation
for Bit Index Explicit Replication (BIER) in MPLS and Non-
MPLS Networks", RFC 8296, DOI 10.17487/RFC8296, January
2018, <https://www.rfc-editor.org/info/rfc8296>.
Authors' Addresses Authors' Addresses
Peter Psenak (editor) Peter Psenak (editor)
Cisco Cisco
Apollo Business Center Apollo Business Center
Mlynske nivy 43 Mlynske nivy 43
Bratislava 821 09 Bratislava 821 09
Slovakia Slovakia
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