Internet DRAFT - draft-ietf-ospf-prefix-link-attr
draft-ietf-ospf-prefix-link-attr
Network Working Group P. Psenak
Internet-Draft Cisco Systems
Intended status: Standards Track H. Gredler
Expires: February 21, 2016 Juniper Networks, Inc.
R. Shakir
Individual Contributor
W. Henderickx
Alcatel-Lucent
J. Tantsura
Ericsson
A. Lindem
Cisco Systems
August 20, 2015
OSPFv2 Prefix/Link Attribute Advertisement
draft-ietf-ospf-prefix-link-attr-13.txt
Abstract
OSPFv2 requires functional extension beyond what can readily be done
with the fixed-format Link State Advertisements (LSAs) as described
in RFC 2328. This document defines OSPF opaque LSAs based on Type-
Length-Value (TLV) tuples that can be used to associate additional
attributes with prefixes or links. Dependent on the application,
these prefixes and links may or not be advertised in the fixed-format
LSAs. The OSPF opaque LSAs are optional and fully backward
compatible.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on February 21, 2016.
Psenak, et al. Expires February 21, 2016 [Page 1]
Internet-Draft OSPFv2 Prefix/Link Attributes August 2015
Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
This document may contain material from IETF Documents or IETF
Contributions published or made publicly available before November
10, 2008. The person(s) controlling the copyright in some of this
material may not have granted the IETF Trust the right to allow
modifications of such material outside the IETF Standards Process.
Without obtaining an adequate license from the person(s) controlling
the copyright in such materials, this document may not be modified
outside the IETF Standards Process, and derivative works of it may
not be created outside the IETF Standards Process, except to format
it for publication as an RFC or to translate it into languages other
than English.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements notation . . . . . . . . . . . . . . . . . . 3
2. OSPFv2 Extended Prefix Opaque LSA . . . . . . . . . . . . . . 3
2.1. OSPFv2 Extended Prefix TLV . . . . . . . . . . . . . . . 5
3. OSPFv2 Extended Link Opaque LSA . . . . . . . . . . . . . . . 8
3.1. OSPFv2 Extended Link TLV . . . . . . . . . . . . . . . . 9
4. Backward Compatibility . . . . . . . . . . . . . . . . . . . 10
5. Implementation Status . . . . . . . . . . . . . . . . . . . . 10
5.1. Implementation Survey Results . . . . . . . . . . . . . . 11
6. Security Considerations . . . . . . . . . . . . . . . . . . . 12
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
7.1. OSPF Extended Prefix Opaque LSA TLV Registry . . . . . . 13
7.2. OSPF Extended Prefix TLV Sub-TLV Registry . . . . . . . . 13
7.3. OSPF Extended Prefix TLV Flags Registry . . . . . . . . . 13
7.4. OSPF Extended Link Opaque LSA TLV Registry . . . . . . . 14
7.5. OSPF Extended Link TLV Sub-TLV Registry . . . . . . . . . 14
8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 14
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
9.1. Normative References . . . . . . . . . . . . . . . . . . 15
Psenak, et al. Expires February 21, 2016 [Page 2]
Internet-Draft OSPFv2 Prefix/Link Attributes August 2015
9.2. Informative References . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16
1. Introduction
OSPFv2 requires functional extension beyond what can readily be done
with the fixed-format Link State Advertisements (LSAs) as described
in RFC 2328 [OSPFV2]. This document defines OSPF opaque LSAs based
on Type-Length-Value (TLV) tuples that can be used to associate
additional attributes with prefixes or links. Dependent on the
application, these prefixes and links may or not be advertised in the
fixed-format LSAs. The OSPF opaque LSAs are optional and fully
backward compatible. This is in contrast to the approach taken in
OSPFv3 [I-D.ietf-ospf-ospfv3-lsa-extend] where the existing LSAs will
be replaced by TLV-based extended LSAs.
New requirements such as source/destination routing, route tagging,
and segment routing necessitate this extension.
This specification defines the following OSPFv2 opaque LSAs:
1. OSPFv2 Extended Prefix Opaque LSA - Allows advertisement of
additional attributes for prefixes advertised in Router-LSAs,
Network-LSAs, Network-Summary-LSAs, NSSA-LSAs, and AS-External-
LSAs [OSPFV2]
2. OSPFv2 Extended Link Opaque LSA - Allows advertisement of
additional attributes for links advertised in Router-LSAs.
Additionally, the following TLVs are defined:
1. OSPFv2 Extended Prefix TLV - Top-level TLV advertising attributes
for a prefix in the OSPFv2 Extended Prefix Opaque LSA.
2. OSPFv2 Extended Link TLV - Top-level TLV advertising attributes
for a link in the OSPFv2 Extended Link Opaque LSA.
1.1. Requirements notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC-KEYWORDS].
2. OSPFv2 Extended Prefix Opaque LSA
The OSPFv2 Extended Prefix Opaque LSA will be used to advertise
additional prefix attributes. Opaque LSAs are described in [OPAQUE].
Psenak, et al. Expires February 21, 2016 [Page 3]
Internet-Draft OSPFv2 Prefix/Link Attributes August 2015
Multiple OSPFv2 Extended Prefix Opaque LSAs can be advertised by an
OSPFv2 router. The flooding scope of the OSPFv2 Extended Prefix
Opaque LSA depends on the scope of the advertised prefixes and is
under the control of the advertising router. In some cases (e.g.,
mapping server deployment [SEGMENT-ROUTING]), the LSA flooding scope
may be greater than the scope of the corresponding prefixes.
The format of the OSPFv2 Extended Prefix Opaque LSA is as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LS age | Options | LS Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opaque type | Opaque ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Advertising Router |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LS sequence number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LS checksum | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+- TLVs -+
| ... |
OSPFv2 Extended Prefix Opaque LSA
The opaque type used by OSPFv2 Extended Prefix Opaque LSA is 7. The
opaque type is used to differentiate the various type of OSPFv2
Opaque LSA and is described in section 3 of [OPAQUE]. The LS Type
may be 10 or 11 indicating that the Opaque LSA flooding scope is
area-local (10) or AS-wide (11) [OPAQUE]. The LSA "Length" field
[OSPFV2] represents the total length (in octets) of the Opaque LSA
including the LSA header and all TLVs (including padding).
The Opaque ID field is an arbitrary value used to maintain multiple
Extended Prefix Opaque LSAs. For OSPFv2 Extended Prefix Opaque LSAs,
the Opaque ID has no semantic significance other than to
differentiate Extended Prefix Opaque LSAs originated by the same
OSPFv2 router. If multiple Extended Prefix Opaque LSAs include the
same prefix, the attributes from the Opaque LSA with the lowest
Opaque ID SHOULD be used.
The format of the TLVs within the body of the OSPFv2 Extended Prefix
Opaque LSA is the same as the format used by the Traffic Engineering
Extensions to OSPF [TE]. The variable TLV section consists of one or
Psenak, et al. Expires February 21, 2016 [Page 4]
Internet-Draft OSPFv2 Prefix/Link Attributes August 2015
more nested Type/Length/Value (TLV) tuples. Nested TLVs are also
referred to as sub-TLVs. The format of each TLV 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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value |
o
o
o
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
TLV Format
The Length field defines the length of the value portion in octets
(thus a TLV with no value portion would have a length of 0). The TLV
is padded to 4-octet alignment; padding is not included in the length
field (so a 3-octet value would have a length of 3, but the total
size of the TLV would be 8 octets). Nested TLVs are also 32-bit
aligned. For example, a 1-byte value would have the length field set
to 1, and 3 octets of padding would be added to the end of the value
portion of the TLV. The padding is composed of zeros.
2.1. OSPFv2 Extended Prefix TLV
The OSPF Extended Prefix TLV is used to advertise additional
attributes associated with the prefix. Multiple OSPF Extended Prefix
TLVs MAY be advertised in each OSPFv2 Extended Prefix Opaque LSA.
However, since the opaque LSA type defines the flooding scope, the
LSA flooding scope MUST satisfy the application specific requirements
for all the prefixes included in a single OSPFv2 Extended Prefix
Opaque LSA. The OSPF Extended Prefix TLV has the following format:
Psenak, et al. Expires February 21, 2016 [Page 5]
Internet-Draft OSPFv2 Prefix/Link Attributes August 2015
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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Route Type | Prefix Length | AF | Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address Prefix (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub-TLVs (variable) |
+- -+
| |
OSPFv2 Extended Prefix TLV
Type
The TLV type. The value is 1 for this TLV type.
Length
Variable dependent on sub-TLVs.
Route Type
Route type: type of the OSPF route. If the route type is 0
(Unspecified), the information inside the OSPF External Prefix TLV
applies to the prefix regardless of prefix's route-type. This is
useful when prefix specific attributes are advertised by an
external entity that is not aware of the route-type associated
with the prefix. Supported types are:
0 - Unspecified
1 - Intra-Area
3 - Inter-Area
5 - AS External
7 - NSSA External
These route types correspond directly to the OSPFv2 LSAs types as
defined in http://www.iana.org/assignments/ospfv2-parameters/
ospfv2-parameters.xhtml#ospfv2-parameters-5. Specification of
route types other than those defined will prevent correlation with
existing OSPFv2 LSAs and is beyond the scope this specification.
Prefix Length
Psenak, et al. Expires February 21, 2016 [Page 6]
Internet-Draft OSPFv2 Prefix/Link Attributes August 2015
Length in the prefix in bits.
AF
Address family for the prefix. Currently, the only supported
value is 0 for IPv4 unicast. The inclusion of address family in
this TLV allows for future extension.
Flags
This one octet field contains flags applicable to the prefix.
Supported Flags include:
0x80 - A-Flag (Attach flag): An Area Border Router (ABR)
generating an Extended Prefix TLV for inter-area prefix that is
locally connected or attached in other connected area SHOULD
set this flag.
0x40 - N-Flag (Node Flag): Set when the prefix identifies the
advertising router i.e., the prefix is a host prefix
advertising a globally reachable address typically associated
with a loopback address. The advertising router MAY choose to
not set this flag even when the above conditions are met. If
the flag is set and the prefix length is not a host prefix then
the flag MUST be ignored. The flag is preserved when the
OSPFv2 Extended Prefix Opaque LSA is propagated between areas.
Address Prefix
For the address family IPv4 unicast, the prefix itself encoded as
a 32-bit value. The default route is represented by a prefix of
length 0. Prefix encoding for other address families is beyond
the scope of this specification.
If this TLV is advertised multiple times for the same prefix in the
same OSPFv2 Extended Prefix Opaque LSA, only the first instance of
the TLV is used by receiving OSPFv2 Routers. This situation SHOULD
be logged as an error.
If this TLV is advertised multiple times for the same prefix in
different OSPFv2 Extended Prefix Opaque LSAs originated by the same
OSPF router, the OSPF advertising router is re-originating Extended
Prefix Opaque LSAs for multiple prefixes and is most likely repacking
Extended-Prefix-TLVs in Extended Prefix Opaque LSAs. In this case,
the Extended-Prefix-TLV in the Extended Prefix Opaque LSA with the
smallest Opaque ID is used by receiving OSPFv2 Routers. This
situation may be logged as a warning.
It is RECOMMENDED that OSPF routers advertising Extended Prefix TLVs
in different Extended Prefix Opaque LSAs re-originate these LSAs in
ascending order of Opaque ID to minimize the disruption.
Psenak, et al. Expires February 21, 2016 [Page 7]
Internet-Draft OSPFv2 Prefix/Link Attributes August 2015
If this TLV is advertised multiple times for the same prefix in
different OSPFv2 Extended Prefix Opaque LSAs originated by different
OSPF routers, the application using the information is required to
determine which OSPFv2 Extended Prefix Opaque LSA is used. For
example, the application could prefer the LSA providing the best path
to the prefix.
This document creates a registry for OSPF Extended Prefix sub-TLVs in
Section 7.
3. OSPFv2 Extended Link Opaque LSA
The OSPFv2 Extended Link Opaque LSA will be used to advertise
additional link attributes. Opaque LSAs are described in [OPAQUE].
The OSPFv2 Extended Link Opaque LSA has an area flooding scope.
Multiple OSPFv2 Extended Link Opaque LSAs can be advertised by a
single router in an area.
The format of the OSPFv2 Extended Link Opaque LSA is as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LS age | Options | LS Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Opaque type | Opaque ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Advertising Router |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LS sequence number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| LS checksum | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+- TLVs -+
| ... |
OSPFv2 Extended Link Opaque LSA
The Opaque type used by OSPFv2 Extended Link Opaque LSA is 8. The LS
Type is 10 indicating that the Opaque LSA flooding scope is area-
local [OPAQUE]. The opaque type is used to differentiate the various
type of OSPFv2 Opaque LSA and is described in section 3 of [OPAQUE].
The LSA "Length" field [OSPFV2] represents the total length (in
octets) of the Opaque LSA including the LSA header and all TLVs
(including padding).
Psenak, et al. Expires February 21, 2016 [Page 8]
Internet-Draft OSPFv2 Prefix/Link Attributes August 2015
The Opaque ID field is an arbitrary value used to maintain multiple
Extended Prefix Opaque LSAs. For OSPFv2 Extended Link Opaque LSAs,
the Opaque ID has no semantic significance other than to
differentiate Extended Link Opaque LSAs originated by the same OSPFv2
router. If multiple Extended Link Opaque LSAs include the same link,
the attributes from the Opaque LSA with the lowest Opaque ID will be
used.
The format of the TLVs within the body of the OSPFv2 Extended Link
Opaque LSA is the same as described in Section 2.
3.1. OSPFv2 Extended Link TLV
The OSPFv2 Extended Link TLV is used to advertise various attributes
of the link. It describes a single link and is constructed of a set
of Sub-TLVs. There are no ordering requirements for the Sub-TLVs.
Only one Extended Link TLV SHALL be advertised in each Extended Link
Opaque LSA, allowing for fine granularity changes in the topology.
The Extended Link TLV has following format:
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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link-Type | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link Data |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub-TLVs (variable) |
+- -+
| |
OSPFv2 Extended Link TLV
Type
The TLV type. The value is 1 for this TLV type.
Length
Variable dependent on sub-TLVs.
Link-Type
Psenak, et al. Expires February 21, 2016 [Page 9]
Internet-Draft OSPFv2 Prefix/Link Attributes August 2015
Link-Type is defined in section A.4.2 of [OSPFV2] and
http://www.iana.org/assignments/ospfv2-parameters/
ospfv2-parameters.xhtml#ospfv2-parameters-6. Specification of
link types other than those defined will prevent correlation with
existing OSPFv2 Router-LSA links and is beyond the scope this
specification.
Link-ID
Link-ID is defined in section A.4.2 of [OSPFV2].
Link Data
Link-Data is defined in section A.4.2 of [OSPFV2].
If this TLV is advertised multiple times in the same OSPFv2 Extended
Link Opaque LSA, only the first instance of the TLV is used by
receiving OSPFv2 Routers. This situation SHOULD be logged as an
error.
If this TLV is advertised multiple times for the same link in
different OSPFv2 Extended Link Opaque LSAs originated by the same
OSPF router, the Extended Link TLV in the Extended Link Opaque LSA
with the smallest Opaque ID is used by receiving OSPFv2 Routers.
This situation may be logged as a warning.
It is RECOMMENDED that OSPF routers advertising Extended Link TLVs in
different Extended Link Opaque LSAs re-originate these LSAs in
ascending order of Opaque ID to minimize the disruption.
This document creates a registry for OSPF Extended Link sub-TLVs in
Section 7.
4. Backward Compatibility
Since opaque OSPFv2 LSAs are optional and backward compatible
[OPAQUE], the extensions described herein are fully backward
compatible. However, future OSPFv2 applications utilizing these
extensions MUST address backward compatibility of the corresponding
functionality.
5. Implementation Status
Note to RFC Editor: this section may be removed on publication as an
RFC.
This section records the status of known implementations of the
protocol defined by this specification at the time of posting of this
Internet-Draft, and is based on a proposal described in RFC 6982.
The description of implementations in this section is intended to
Psenak, et al. Expires February 21, 2016 [Page 10]
Internet-Draft OSPFv2 Prefix/Link Attributes August 2015
assist the IETF in its decision processes in progressing drafts to
RFCs. Please note that the listing of any individual implementation
here does not imply endorsement by the IETF. Furthermore, no effort
has been spent to verify the information presented here that was
supplied by IETF contributors. This is not intended as, and must not
be construed to be, a catalog of available implementations or their
features. Readers are advised to note that other implementations may
exist.
According to RFC 6982, "this will allow reviewers and working groups
to assign due consideration to documents that have the benefit of
running code, which may serve as evidence of valuable experimentation
and feedback that have made the implemented protocols more mature.
It is up to the individual working groups to use this information as
they see fit".
5.1. Implementation Survey Results
An implementation survey with seven questions related to the
implementer's support of OSPFv2 Prefix/Link Attributes was sent to
the OSPF WG list and several known implementers. This section
contains responses from four implementers who completed the survey.
No external means were used to verify the accuracy of the information
submitted by the respondents. The respondents are considered experts
on the products they reported on. Additionally, responses were
omitted from implementers who indicated that they have not
implemented the function yet.
Four vendors and one open source entity replied to the survey. These
included Alcatel-Lucent, Cisco, Huawei, Juniper, and FreeRouter
(http://freerouter.nop.hu). Cisco and Alcatel-Lucent also did
interoperability testing. FreeRouter did interoperability testing
with Cisco. The Cisco, Alcatel-Lucent, and FreeRouter
implementations are in released software versions. The Huawei and
Juniper implementation software releases are pending. For prefix
attributes, the recent change incorporating the A-Flag is pending
implementation for all four vendors. The FreeRouter implementation
includes support for the A-Flag. Implementation of the N-flag is
pending for the Huawei and Juniper implementations. Otherwise, all
the survey respondents have full implementations. For all four
vendors and the FreeRouter implementation, segment routing
[SEGMENT-ROUTING] was an application making use of the extensions.
Additionally, Cisco has implemented Topology-Independent Loop-Free
Alternatives (TI-LFA) [TI-LFA] and Bit Indexed Egress Replication
(BIER) advertisement [BIER].
Alcatel-Lucent's support of this specification is included in SR OS,
Release 13.0.R4. Cisco's support is included in IOS-XR 5.3.2. The
Psenak, et al. Expires February 21, 2016 [Page 11]
Internet-Draft OSPFv2 Prefix/Link Attributes August 2015
FreeRouter implementation is available in the FreeRouter 15.6.4
distribution. Huawei and Juniper will respectively provide support
in future versions Versatile Routing Platform (VRP) and JUniper
Network Operating System (JUNOS).
6. Security Considerations
In general, new LSAs defined in this document are subject to the same
security concerns as those described in [OSPFV2] and [OPAQUE].
OSPFv2 applications utilizing these OSPFv2 extensions must define the
security considerations relating to those applications in the
specifications corresponding to those applications.
Additionally, implementations must assure that malformed TLV and Sub-
TLV permutations are detected and do not provide a vulnerability for
attackers to crash the OSPFv2 router or routing process. Malformed
LSAs MUST NOT be stored in the Link State Database (LSDB),
acknowledged, or reflooded. Reception of malformed LSAs SHOULD be
counted and/or logged for further analysis. In this context, a
malformed LSA is one which cannot be parsed due to a TLV or Sub-TLV
overrunning the end of the subsuming LSA, TLV, or sub-TLV or where
there is data remaining to be parsed but the length of the remaining
data is less than the size of a TLV header.
7. IANA Considerations
This specification updates the Opaque Link-State Advertisements (LSA)
Option Types with the following values:
o 7 (IANA Early Allocation [RFC7120]) - OSPFv2 Extended Prefix
Opaque LSA
o 8 (IANA Early Allocation [RFC7120]) - OSPFv2 Extended Link Opaque
LSA
This specification also creates five new registries:
o OSPF Extended Prefix Opaque LSA TLVs
o OSPF Extended Prefix TLV Sub-TLVs
o OSPF Extended Prefix TLV Flags
o OSPF Extended Link Opaque LSA TLVs
o OSPF Extended Link TLV Sub-TLVs
Psenak, et al. Expires February 21, 2016 [Page 12]
Internet-Draft OSPFv2 Prefix/Link Attributes August 2015
7.1. OSPF Extended Prefix Opaque LSA TLV Registry
The "OSPF Extend Prefix Opaque LSA TLV" registry will define top-
level TLVs for the Extended Prefix Opaque LSAs and should be added to
the "Open Shortest Path First v2 (OSPFv2) Parameters" registries
group. New values can be allocated via IETF Review or IESG Approval.
The following initial values are allocated:
o 0 - Reserved
o 1 - OSPF Extended Prefix TLV
Types in the range 32768-33023 are for experimental use; these will
not be registered with IANA, and MUST NOT be mentioned by RFCs.
Types in the range 33024-65535 are not to be assigned at this time.
Before any assignments can be made in the 33024-65535 range, there
MUST be an IETF specification that specifies IANA Considerations that
covers the range being assigned.
7.2. OSPF Extended Prefix TLV Sub-TLV Registry
The "OSPF Extended Prefix TLV sub-TLV" registry will define sub-TLVs
at any level of nesting for Extended Prefix TLVs and should be added
to the "Open Shortest Path First v2 (OSPFv2) Parameters" registries
group. New values can be allocated via IETF Review or IESG Approval.
The following initial values are allocated:
o 0 - Reserved
Types in the range 32768-33023 are for experimental use; these will
not be registered with IANA, and MUST NOT be mentioned by RFCs.
Types in the range 33024-65535 are not to be assigned at this time.
Before any assignments can be made in the 33024-65535 range, there
MUST be an IETF specification that specifies IANA Considerations that
covers the range being assigned.
7.3. OSPF Extended Prefix TLV Flags Registry
The "OSPF Extended Prefix TLV Flags" registry will define the bits in
the 8-bit Extended Prefix TLV Flags (Section 2.1). This
specification defines the N (0x80) and A (0x40) bits. The registry
should be added to the "Open Shortest Path First v2 (OSPFv2)
Parameters" registries group. New values can be allocated via IETF
Review or IESG Approval.
Psenak, et al. Expires February 21, 2016 [Page 13]
Internet-Draft OSPFv2 Prefix/Link Attributes August 2015
7.4. OSPF Extended Link Opaque LSA TLV Registry
The "OSPF Extended Link Opaque LSA TLV" registry will define top-
level TLVs for Extended Link Opaque LSAs and should be added to the
"Open Shortest Path First v2 (OSPFv2) Parameters" registries group.
New values can be allocated via IETF Review or IESG Approval.
Following initial values are allocated:
o 0 - Reserved
o 1 - OSPFv2 Extended Link TLV
Types in the range 32768-33023 are for experimental use; these will
not be registered with IANA, and MUST NOT be mentioned by RFCs.
Types in the range 33024-65535 are not to be assigned at this time.
Before any assignments can be made in the 33024-65535 range, there
MUST be am IETF specification that specifies IANA Considerations that
covers the range being assigned.
7.5. OSPF Extended Link TLV Sub-TLV Registry
The OSPF Extended Link TLV sub-TLV registry will define sub-TLVs at
any level of nesting for Extended Link TLVs and should be added to
the "Open Shortest Path First v2 (OSPFv2) Parameters" registries
group. New values can be allocated via IETF Review or IESG Approval.
The following initial values are allocated:
o 0 - Reserved
Types in the range 32768-33023 are for experimental use; these will
not be registered with IANA, and MUST NOT be mentioned by RFCs.
Types in the range 33024-65535 are not to be assigned at this time.
Before any assignments can be made in the 33024-65535 range, there
MUST be an IETF specification that specifies IANA Considerations that
covers the range being assigned.
8. Acknowledgments
We would like to thank Anton Smirnov for his contribution.
Thanks to Tony Przygienda for his review and comments.
Thanks to Wim Henderickx, Greg Harkins, Peter Psenak, Eric Wu,
Shraddha Hegde, and Csaba Mate for their responses to the
implementation survey.
Psenak, et al. Expires February 21, 2016 [Page 14]
Internet-Draft OSPFv2 Prefix/Link Attributes August 2015
Thanks to Tom Petch for review and comments.
Thanks to Alia Atlas and Alvaro Retana for AD review and comments.
Thanks to Carlos Pignataro and Ron Bonica for Operations Directorate
review and comments.
Thanks to Suresh Krishnan for Gen-ART review and comments.
Thanks to Ben Campbell, Kathleen Moriarty, and Barry Leiba for IESG
review and comments.
9. References
9.1. Normative References
[OPAQUE] Berger, L., Bryskin, I., Zinin, A., and R. Coltun, "The
OSPF Opaque LSA Option", RFC 5250, July 2008.
[OSPFV2] Moy, J., "OSPF Version 2", RFC 2328, April 1998.
[RFC-KEYWORDS]
Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", RFC 2119, March 1997.
[TE] Katz, D., Yeung, D., and K. Kompella, "Traffic Engineering
Extensions to OSPF", RFC 3630, September 2003.
9.2. Informative References
[BIER] Psenak, P., Kumar, N., Wijnands, I., Dolganow, A.,
Przygienda, T., Zhang, J., and S. Aldrin, "OSPF Extensions
for BIER", draft-ietf-bier-ospf-bier-extensions-00.txt
(work in progress), April 2015.
[I-D.ietf-ospf-ospfv3-lsa-extend]
Lindem, A., Mirtorabi, S., Roy, A., and F. Baker, "OSPFv3
LSA Extendibility", draft-ietf-ospf-ospfv3-lsa-extend-06
(work in progress), February 2015.
[RFC7120] Cotton, M., "Early IANA Allocation of Standards Track Code
Points", BCP 100, RFC 7120, January 2014.
[SEGMENT-ROUTING]
Psenak, P., Previdi, S., Filsfils, C., Gredler, H.,
Shakir, R., Henderickx, W., and J. Tantsura, "OSPF
Extensions for Segment Routing", draft-ietf-ospf-segment-
routing-extensions-05.txt (work in progress), June 2015.
Psenak, et al. Expires February 21, 2016 [Page 15]
Internet-Draft OSPFv2 Prefix/Link Attributes August 2015
[TI-LFA] Francois, P., Filsfils, C., Bashandy, A., Decraene, B.,
and S. Litkowski, "Topology Independent Fast Reroute using
Segment Routing", draft-francois-rtgwg-segment-routing-ti-
lfa-00.txt (work in progress), August 2014.
Authors' Addresses
Peter Psenak
Cisco Systems
Apollo Business Center
Mlynske nivy 43
Bratislava, 821 09
Slovakia
Email: ppsenak@cisco.com
Hannes Gredler
Juniper Networks, Inc.
1194 N. Mathilda Ave.
Sunnyvale, CA 94089
USA
Email: hannes@juniper.net
Rob Shakir
Individual Contributor
London
UK
Email: rjs@rob.sh
Wim Henderickx
Alcatel-Lucent
Copernicuslaan
Antwerp, 2018 94089
Belgium
Email: wim.henderickx@alcatel-lucent.com
Psenak, et al. Expires February 21, 2016 [Page 16]
Internet-Draft OSPFv2 Prefix/Link Attributes August 2015
Jeff Tantsura
Ericsson
300 Holger Way
San Jose, CA 95134
USA
Email: jeff.tantsura@ericsson.com
Acee Lindem
Cisco Systems
301 Midenhall Way
Cary, NC 27513
USA
Email: acee@cisco.com
Psenak, et al. Expires February 21, 2016 [Page 17]
