draft-ietf-rtgwg-multihomed-prefix-lfa-06.txt   draft-ietf-rtgwg-multihomed-prefix-lfa-07.txt 
Routing Area Working Group P. Sarkar, Ed. Routing Area Working Group P. Sarkar, Ed.
Internet-Draft Arrcus, Inc. Internet-Draft Arrcus, Inc.
Updates: 5286 (if approved) S. Hegde Updates: 5286 (if approved) U. Chunduri, Ed.
Intended status: Standards Track Juniper Networks, Inc. Intended status: Standards Track Huawei USA
Expires: August 12, 2018 U. Chunduri, Ed. Expires: March 23, 2019 S. Hegde
Huawei USA Juniper Networks, Inc.
J. Tantsura J. Tantsura
Nuage Networks Nuage Networks
H. Gredler H. Gredler
RtBrick, Inc. RtBrick, Inc.
February 8, 2018 September 19, 2018
LFA selection for Multi-Homed Prefixes LFA selection for Multi-Homed Prefixes
draft-ietf-rtgwg-multihomed-prefix-lfa-06 draft-ietf-rtgwg-multihomed-prefix-lfa-07
Abstract Abstract
This document shares experience gained from implementing algorithms This document shares experience gained from implementing algorithms
to determine Loop-Free Alternates for multi-homed prefixes. In to determine Loop-Free Alternates for multi-homed prefixes. In
particular, this document provides explicit inequalities that can be particular, this document provides explicit inequalities that can be
used to evaluate neighbors as a potential alternates for multi-homed used to evaluate neighbors as a potential alternates for multi-homed
prefixes. It also provides detailed criteria for evaluating prefixes. It also provides detailed criteria for evaluating
potential alternates for external prefixes advertised by OSPF ASBRs. potential alternates for external prefixes advertised by OSPF ASBRs.
This documents updates and expands some of the "Routing Aspects" as This documents updates and expands some of the "Routing Aspects" as
specified in Section 6 of RFC 5286. specified in Section 6 of RFC 5286.
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 RFC2119 [RFC2119]. document are to be interpreted as described in RFC8174 [RFC8174].
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 August 12, 2018. This Internet-Draft will expire on March 23, 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
skipping to change at page 2, line 28 skipping to change at page 2, line 28
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 . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . 3
2. LFA inequalities for MHPs . . . . . . . . . . . . . . . . . . 4 2. LFA inequalities for MHPs . . . . . . . . . . . . . . . . . . 4
3. LFA selection for the multi-homed prefixes . . . . . . . . . 4 3. LFA selection for the multi-homed prefixes . . . . . . . . . 4
3.1. Improved coverage with simplified approach to MHPs . . . 6 3.1. Improved coverage with simplified approach to MHPs . . . 6
3.2. IS-IS ATT Bit considerations . . . . . . . . . . . . . . 8 3.2. IS-IS ATT Bit considerations . . . . . . . . . . . . . . 7
4. LFA selection for the multi-homed external prefixes . . . . . 8 4. LFA selection for the multi-homed external prefixes . . . . . 8
4.1. IS-IS . . . . . . . . . . . . . . . . . . . . . . . . . . 8 4.1. IS-IS . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.2. OSPF . . . . . . . . . . . . . . . . . . . . . . . . . . 8 4.2. OSPF . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.2.1. Rules to select alternate ASBR . . . . . . . . . . . 9 4.2.1. Rules to select alternate ASBR . . . . . . . . . . . 8
4.2.2. Multiple ASBRs belonging different area . . . . . . . 10 4.2.1.1. Multiple ASBRs belonging different area . . . . . 9
4.2.3. Type 1 and Type 2 costs . . . . . . . . . . . . . . . 11 4.2.1.2. Type 1 and Type 2 costs . . . . . . . . . . . . . 10
4.2.4. RFC1583compatibility is set to enabled . . . . . . . 11 4.2.1.3. RFC1583compatibility is set to enabled . . . . . 10
4.2.5. Type 7 routes . . . . . . . . . . . . . . . . . . . . 11 4.2.1.4. Type 7 routes . . . . . . . . . . . . . . . . . . 10
4.2.6. Inequalities to be applied for alternate ASBR 4.2.2. Inequalities to be applied for alternate ASBR
selection . . . . . . . . . . . . . . . . . . . . . . 11 selection . . . . . . . . . . . . . . . . . . . . . . 11
4.2.6.1. Forwarding address set to non-zero value . . . . 11 4.2.2.1. Forwarding address set to non-zero value . . . . 11
4.2.6.2. ASBRs advertising type1 and type2 cost . . . . . 12 4.2.2.2. ASBRs advertising type1 and type2 cost . . . . . 11
5. LFA Extended Procedures . . . . . . . . . . . . . . . . . . . 13 5. LFA Extended Procedures . . . . . . . . . . . . . . . . . . . 12
5.1. Links with IGP MAX_METRIC . . . . . . . . . . . . . . . . 13 5.1. Links with IGP MAX_METRIC . . . . . . . . . . . . . . . . 12
5.2. Multi Topology Considerations . . . . . . . . . . . . . . 14 5.2. Multi Topology Considerations . . . . . . . . . . . . . . 13
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14
8. Contributing Authors . . . . . . . . . . . . . . . . . . . . 15 8. Contributing Authors . . . . . . . . . . . . . . . . . . . . 14
9. Security Considerations . . . . . . . . . . . . . . . . . . . 16 9. Security Considerations . . . . . . . . . . . . . . . . . . . 15
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 16 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
10.1. Normative References . . . . . . . . . . . . . . . . . . 16 10.1. Normative References . . . . . . . . . . . . . . . . . . 15
10.2. Informative References . . . . . . . . . . . . . . . . . 16 10.2. Informative References . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16
1. Introduction 1. Introduction
The use of Loop-Free Alternates (LFA) for IP Fast Reroute is A framework for the development of IP fast- reroute mechanisms is
specified in [RFC5286]. Section 6.1 of [RFC5286] describes a method detailed in [RFC5714]. The use of Loop-Free Alternates (LFA) for IP
to determine loop-free alternates for a multi-homed prefixes (MHPs). Fast Reroute is specified in [RFC5286]. Section 6.1 of [RFC5286]
This document describes a procedure using explicit inequalities that describes a method to determine loop-free alternates for multi-homed
can be used by a computing router to evaluate a neighbor as a prefixes (MHPs). This document describes a procedure using explicit
potential alternate for a multi-homed prefix. The results obtained inequalities that can be used by a computing router to evaluate a
are equivalent to those obtained using the method described in neighbor as a potential alternate for a multi-homed prefix. The
Section 6.1 of [RFC5286]. However, some may find this formulation results obtained are equivalent to those obtained using the method
useful. described in Section 6.1 of [RFC5286]. However, some may find this
formulation useful.
Section 6.3 of [RFC5286] discusses complications associated with Section 6.3 of [RFC5286] discusses complications associated with
computing LFAs for multi-homed prefixes in OSPF. This document computing LFAs for multi-homed prefixes in OSPF. This document
provides detailed criteria for evaluating potential alternates for provides detailed criteria for evaluating potential alternates for
external prefixes advertised by OSPF ASBRs, as well as explicit external prefixes advertised by OSPF ASBRs, as well as explicit
inequalities. inequalities.
This document also provide clarifications, additional considerations This document also provides clarifications, additional considerations
to [RFC5286], to address a few coverage and operational observations. to [RFC5286], to address a few coverage and operational observations.
These observations are in the area of handling IS-IS attach (ATT) bit These observations are in the area of handling IS-IS attach (ATT) bit
in Level-1 (L1) area, links provisioned with MAX_METRIC for traffic in Level-1 (L1) area, links provisioned with MAX_METRIC for traffic
engineering (TE) purposes and in the area of Multi Topology (MT) IGP engineering (TE) purposes and in the area of Multi Topology (MT) IGP
deployments. These are elaborated in detail in Section 3.2 and deployments. These are elaborated in detail in Section 3.2 and
Section 5. Section 5.
1.1. Acronyms 1.1. Acronyms
AF - Address Family AF - Address Family
skipping to change at page 4, line 36 skipping to change at page 4, line 36
computing alternates computing alternates
S - The computing router S - The computing router
N - The alternate router being evaluated N - The alternate router being evaluated
E - The primary next-hop on shortest path from S to E - The primary next-hop on shortest path from S to
prefix P. prefix P.
PO_i - The specific prefix-originating router being PO_i - The specific prefix-originating router being
evaluated. evaluated.
PO_best - The prefix-originating router on the shortest path PO_best - The prefix-originating router on the shortest path
from the computing router S to prefix P. from the computing router S to prefix P.
Cost (X,P) - Cost of reaching the prefix P from prefix Cost (X,P) - Cost of reaching the prefix P from prefix
originating node X. originating node X.
D_opt(X,Y) - Distance on the shortest path from node X to node D_opt(X,Y) - Distance on the shortest path from node X to node
Y. Y.
Figure 1: LFA inequalities for MHPs Figure 1: LFA inequalities for MHPs
3. LFA selection for the multi-homed prefixes 3. LFA selection for the multi-homed prefixes
To compute a valid LFA for a given multi-homed prefix P, a computing To compute a valid LFA for a given multi-homed prefix P, a computing
router S MUST follow one of the appropriate procedures below, for router S MUST follow one of the appropriate procedures below, for
each alternate neighbor N. each alternate neighbor N.
skipping to change at page 5, line 38 skipping to change at page 5, line 38
the metric advertised by N for the prefix P). the metric advertised by N for the prefix P).
2. Else, evaluate the appropriate node-protecting LFA inequality 2. Else, evaluate the appropriate node-protecting LFA inequality
for P with the N as the alternate neighbor. for P with the N as the alternate neighbor.
2.a. If LFA inequality condition is met, 2.a. If LFA inequality condition is met,
select N as a LFA for prefix P. select N as a LFA for prefix P.
2.b. Else, N is not a LFA for prefix P. 2.b. Else, N is not a LFA for prefix P.
Figure 2: Rules for selecting LFA for MHPs Figure 2: Rules for selecting LFA for MHPs
In case an alternate neighbor N is also one of the prefix-originators In case an alternate neighbor N is also one of the prefix-originators
of prefix P, N MAY be selected as a valid LFA for P since being a of prefix P, N being a prefix-originator it is guaranteed that N will
prefix-originator it is guaranteed that N will not loop back packets not loop back packets destined for prefix P to computing router S.
destined for prefix P to computing router S. So N MUST be chosen as a valid LFA for prefix P, without evaluating
any of the inequalities in Figure 1 as long as downstream-paths-only
LFA is not desired. To ensure such a neighbor N also provides a
downstream-paths-only LFA, router S MUST also evaluate the
downstream-only LFA inequality specified in Figure 1 for neighbor N
and ensure router N satisfies the inequality.
However, if N is not a prefix-originator of P, the computing router However, if N is not a prefix-originator of P, the computing router
SHOULD evaluate one of the corresponding LFA inequalities, as SHOULD evaluate one of the corresponding LFA inequalities, as
mentioned in Figure 1, once for each remote node that originated the mentioned in Figure 1, once for each remote node that originated the
prefix. In case the inequality is satisfied by the neighbor N router prefix. In case the inequality is satisfied by the neighbor N router
S MUST choose neighbor N, as one of the valid LFAs for the prefix P. S MUST choose neighbor N, as one of the valid LFAs for the prefix P.
When computing a downstream-only LFA, in addition to being a prefix-
originator of P, router N MUST also satisfy the downstream-only LFA
inequality specified in Figure 1.
For more specific rules please refer to the later sections of this For more specific rules please refer to the later sections of this
document. document.
3.1. Improved coverage with simplified approach to MHPs 3.1. Improved coverage with simplified approach to MHPs
LFA base specification [RFC5286] Section 6.1 recommends that a router LFA base specification [RFC5286] Section 6.1 recommends that a router
compute the alternate next-hop for an IGP multi-homed prefix by computes the alternate next-hop for an IGP multi-homed prefix by
considering alternate paths via all routers that have announced that considering alternate paths via all routers that have announced that
prefix and the same has been elaborated with appropriate inequalities prefix and the same has been elaborated with appropriate inequalities
in the above section. However, [RFC5286] Section 6.1 also allows for in the above section. However, [RFC5286] Section 6.1 also allows for
the router to simplify the multi-homed prefix calculation by assuming the router to simplify the multi-homed prefix calculation by assuming
that the MHP is solely attached to the router that was its pre- that the MHP is solely attached to the router that was its pre-
failure optimal point of attachment, at the expense of potentially failure optimal point of attachment, at the expense of potentially
lower coverage. If an implementation chooses to simplify the multi- lower coverage. If an implementation chooses to simplify the multi-
homed prefix calculation by assuming that the MHP is solely attached homed prefix calculation by assuming that the MHP is solely attached
to the router that was its pre-failure optimal point of attachment, to the router that was its pre-failure optimal point of attachment,
the procedure described in this memo can potentially improve coverage the procedure described in this memo can potentially improve coverage
for equal cost multi path (ECMP) MHPs without incurring extra for equal cost multi path (ECMP) MHPs without incurring extra
computational cost. computational cost.
The approach specified in [RFC5286] Section 6.1 last paragraph, is to
simplify the MHP as solely attached to the router that was its pre-
failure optimal point of attachment; though it is a scalable approach
and simplifies computation, [RFC5286] notes this MAY result in little
less coverage.
This document improves the above approach to provide loop-free This document improves the above approach to provide loop-free
alternatives without any additional cost for ECMP MHPs as described alternatives without any additional cost for ECMP MHPs as described
through the below example network. The approach specified here MAY through the below example network. The approach specified here MAY
also be applicable for handling default routes as explained in also be applicable for handling default routes as explained in
Section 3.2. Section 3.2.
5 +---+ 8 +---+ 5 +---+ 5 +---+ 8 +---+ 5 +---+
+-----| S |------| A |-----| B | +-----| S |------| A |-----| B |
| +---+ +---+ +---+ | +---+ +---+ +---+
| | | | | |
| 5 | 5 | | 5 | 5 |
| | | | | |
+---+ 5 +---+ 4 +---+ 1 +---+ +---+ 5 +---+ 4 +---+ 1 +---+
| C |---| E |-----| M |-------| F | | C |---| E |-----| M |-------| F |
+---+ +---+ +---+ +---+ +---+ +---+ +---+ +---+
| 10 5 | | 10 5 |
+-----------p---------+ +-----------P---------+
Figure 3: MHP with same ECMP Next-hop Figure 3: MHP with same ECMP Next-hop
In the above network a prefix p, is advertised from both Node E and In the above network a prefix p, is advertised from both Node E and
Node F. With simplified approach taken as specified in [RFC5286] Node F. With simplified approach taken as specified in [RFC5286]
Section 6.1, prefix p will get only link protection LFA through the Section 6.1, prefix P will get only link protection LFA through the
neighbor C while a node protection path is available through neighbor neighbor C while a node protection path is available through neighbor
A. In this scenario, E and F both are pre-failure optimal points of A. In this scenario, E and F both are pre-failure optimal points of
attachment and share the same primary next-hop. Hence, an attachment and share the same primary next-hop. Hence, an
implementation MAY compare the kind of protection A provides to F implementation MAY compare the kind of protection A provides to F
(link-and-node protection) with the kind of protection C provides to (link-and-node protection) with the kind of protection C provides to
E (link protection) and inherit the better alternative to prefix p E (link protection) and inherit the better alternative to prefix P
and here it is A. and here it is A.
However, in the below network prefix p has an ECMP through both node However, in the below network prefix P has an ECMP through both node
E and node F with cost 20. Though it has 2 pre-failure optimal E and node F with cost 20. Though it has 2 pre-failure optimal
points of attachment, the primary next-hop to each pre-failure points of attachment, the primary next-hop to each pre-failure
optimal point of attachment is different. In this case, prefix p optimal point of attachment is different. In this case, prefix P
MUST inherit corresponding LFAs of each primary next-hop calculated MUST inherit corresponding LFAs of each primary next-hop calculated
for the router advertising the same respectively. In the below for the router advertising the same respectively. In the below
diagram that would be node E's and node F's LFA i.e., node N1 and diagram that would be node E's and node F's LFA i.e., node N1 and
node N2 respectively. node N2 respectively.
4 +----+ 4 +----+
+------------------| N2 | +------------------| N2 |
| +----+ | +----+
| | 4 | | 4
10 +---+ 3 +---+ 10 +---+ 3 +---+
+------| S |----------------| B | +------| S |----------------| B |
| +---+ +---+ | +---+ +---+
| | | | | |
| 10 | 1 | | 10 | 1 |
| | | | | |
+----+ 5 +---+ 16 +---+ +----+ 5 +---+ 16 +---+
| N1 |----| E |-----------------| F | | N1 |----| E |-----------------| F |
+----+ +---+ +---+ +----+ +---+ +---+
| 10 16 | | 10 16 |
+-----------p---------+ +-----------P---------+
Figure 4: MHP with different ECMP Next-hops Figure 4: MHP with different ECMP Next-hops
In summary, if there are multiple pre-failure points of attachment In summary, if there are multiple pre-failure points of attachment
for a MHP and primary next-hop of a MHP is same as that of the for a MHP and primary next-hop of a MHP is same as that of the
primary next-hop of the router that was pre-failure optimal point of primary next-hop of the router that was pre-failure optimal point of
attachment, an implementation MAY provide the better protection to attachment, an implementation MAY provide a better protection to MHP
MHP without incurring any additional computation cost. without incurring any additional computation cost.
3.2. IS-IS ATT Bit considerations 3.2. IS-IS ATT Bit considerations
Per [RFC1195] a default route needs to be added in Level1 (L1) router Per [RFC1195] a default route needs to be added in Level1 (L1) router
to the closest reachable Level1/Level2 (L1/L2) router in the network to the closest reachable Level1/Level2 (L1/L2) router in the network
advertising ATT (attach) bit in its LSP-0 fragment. All L1 routers advertising ATT (attach) bit in its LSP-0 fragment. All L1 routers
in the area would do this during the decision process with the next- in the area would do this during the decision process with the next-
hop of the default route set to the adjacent router through which the hop of the default route set to the adjacent router through which the
closest L1/L2 router is reachable. The base LFA specification closest L1/L2 router is reachable. The base LFA specification
[RFC5286] does not specify any procedure for computing LFA for a [RFC5286] does not specify any procedure for computing LFA for a
default route in IS-IS L1 area. This document specifies, potentially default route in IS-IS L1 area. This document specifies, a node can
a node MAY consider a default route is being advertised from the consider a default route is being advertised from the border L1/L2
border L1/L2 router where ATT bit is set and can do LFA computation router where ATT bit is set, and can do LFA computation for that
for the default route. But, when multiple ECMP L1/L2 routers are default route. But, when multiple ECMP L1/L2 routers are reachable
reachable in an L1 area corresponding best LFAs SHOULD be given for in an L1 area corresponding best LFAs SHOULD be given for each
each primary next-hop associated with default route. Considerations primary next-hop associated with default route. Considerations as
as specified in Section 3 and Section 3.1 are applicable for default specified in Section 3 and Section 3.1 are applicable for default
routes, if the default route is considered as ECMP MHP. Note that, routes, if the default route is considered as ECMP MHP. Note that,
this document doesn't alter any ECMP handling rules or computation of this document doesn't alter any ECMP handling rules or computation of
LFAs for ECMP in general as laid out in [RFC5286]. LFAs for ECMP in general as laid out in [RFC5286].
4. LFA selection for the multi-homed external prefixes 4. LFA selection for the multi-homed external prefixes
Redistribution of external routes into IGP is required in case of two Redistribution of external routes into IGP is required in case of two
different networks getting merged into one or during protocol different networks getting merged into one or during protocol
migrations. External routes could be distributed into an IGP domain migrations. External routes could be distributed into an IGP domain
via multiple nodes to avoid a single point of failure. via multiple nodes to avoid a single point of failure.
skipping to change at page 8, line 43 skipping to change at page 8, line 32
ASBR could be used as LFA for the routes redistributed via that ASBR. ASBR could be used as LFA for the routes redistributed via that ASBR.
When there is no LFA available to the best ASBR, it may be desirable When there is no LFA available to the best ASBR, it may be desirable
to consider the other ASBRs (referred to as alternate ASBR hereafter) to consider the other ASBRs (referred to as alternate ASBR hereafter)
redistributing the external routes for LFA selection as defined in redistributing the external routes for LFA selection as defined in
[RFC5286] and leverage the advantage of having multiple re- [RFC5286] and leverage the advantage of having multiple re-
distributing nodes in the network. distributing nodes in the network.
4.1. IS-IS 4.1. IS-IS
LFA evaluation for multi-homed external prefixes in IS-IS is similar LFA evaluation for multi-homed external prefixes in IS-IS is similar
to the multi-homed internal prefixes. Inequalities described in sec to the multi-homed internal prefixes. Inequalities described in
2 would also apply to multi-homed external prefixes as well. Section 2 would also apply to multi-homed external prefixes.
4.2. OSPF 4.2. OSPF
Loop free Alternates [RFC5286] describes mechanisms to apply Loop Free Alternates [RFC5286] describes mechanisms to apply
inequalities to find the loop free alternate neighbor. For the inequalities to find the loop free alternate neighbor. For the
selection of alternate ASBR for LFA consideration, additional rules selection of alternate ASBR for LFA consideration, additional rules
have to be applied in selecting the alternate ASBR due to the have to be applied in selecting the alternate ASBR due to the
external route calculation rules imposed by [RFC2328]. external route calculation rules imposed by [RFC2328].
This document also defines the inequalities defined in [RFC5286] This document defines inequalities specifically for the alternate
specifically for the alternate loop-free ASBR evaluation. loop-free ASBR evaluation, based on those in [RFC5286].
4.2.1. Rules to select alternate ASBR 4.2.1. Rules to select alternate ASBR
The process to select an alternate ASBR is best explained using the The process to select an alternate ASBR is best explained using the
rules below. The below process is applied when primary ASBR for the rules below. The below process is applied when primary ASBR for the
concerned prefix is chosen and there is an alternate ASBR originating concerned prefix is chosen and there is an alternate ASBR originating
same prefix. same prefix.
1. If RFC1583Compatibility is disabled 1. If RFC1583Compatibility is disabled
1a. if primary ASBR and alternate ASBR are intra area 1a. if primary ASBR and alternate ASBR belong to intra area
non-backbone path go to step 2. non-backbone go to step 2.
1b. If primary ASBR and alternate ASBR belong to 1b. If primary ASBR and alternate ASBR belong to
intra-area backbone and/or inter-area path go intra-area backbone and/or inter-area path go
to step 2. to step 2.
1c. for other paths, skip this alternate ASBR and 1c. for other paths, skip this alternate ASBR and
consider next ASBR. consider next ASBR.
2. If cost type (type1/type2) advertised by alternate 2. Compare cost types (type 1/type 2) advertised by alternate ASBR and
ASBR same as primary by the primary ASBR
2a. If not, same skip alternate ASBR and consider next ASBR. 2a. If not the same type skip alternate ASBR and consider next ASBR.
2b. If same proceed to step 3. 2b. If same proceed to step 3.
3. If cost type is type1 3.If cost types are type 1, compare costs advertised by alternate ASBR
3a. If cost is same, program ECMP and return. and by the primary ASBR
3b. else go to step 5. 3a. If costs are the same then program ECMP FRR and return.
3b. else go to step 5..
4 If cost type is type 2 4 If cost types are type 2, compare costs advertised by alternate ASBR
4a. If cost is different, skip alternate ASBR and and by the primary ASBR
consider next ASBR. 4a. If costs are different, skip alternate ASBR and
4b. If type2 cost is same, proceed to step 4c to compare consider next ASBR.
compare type 1 cost. 4b. If cost are the same, proceed to step 4c to compare
4c. If type1 cost is also same program ECMP and return. cost to reach ASBR/forwarding address.
4d. If type 1 cost is different go to step 5. 4c. If cost to reach ASBR/forwarding address are also same program ECMP FRR and return.
4d. If cost to reach ASBR/forwarding address are different go to step 5.
5. If route type (type 5/type 7) 5. If route type (type 5/type 7)
5a. If route type is same, check route p-bit, 5a. If route type is same, check route p-bit,
forwarding address field for routes from both forwarding address field for routes from both
ASBRs match. If p-bit matches proceed to step 6. ASBRs match. If p-bit and forwarding address matches proceed to step 6.
If not, skip this alternate ASBR and consider If not, skip this alternate ASBR and consider
next ASBR. next ASBR.
5b. If route type is not same, skip this alternate ASBR 5b. If route type is not same, skip this alternate ASBR
and consider next alternate ASBR. and consider next alternate ASBR.
6. Apply inequality on the alternate ASBR. 6. Apply inequality on the alternate ASBR.
Figure 5: Rules for selecting alternate ASBR in OSPF Figure 5: Rules for selecting alternate ASBR in OSPF
4.2.2. Multiple ASBRs belonging different area 4.2.1.1. Multiple ASBRs belonging different area
When "RFC1583compatibility" is set to disabled, OSPF [RFC2328] When "RFC1583compatibility" is set to disabled, OSPF [RFC2328]
defines certain rules of preference to choose the ASBRs. While defines certain rules of preference to choose the ASBRs. While
selecting alternate ASBR for loop evaluation for LFA, these rules selecting alternate ASBR for loop evaluation for LFA, these rules
should be applied and ensured that the alternate neighbor does not should be applied to ensure that the alternate neighbor does not
loop the traffic back. cause loop.
When there are multiple ASBRs belonging to different area advertising When there are multiple ASBRs belonging to different area advertising
the same prefix, pruning rules as defined in [RFC2328] section 16.4.1 the same prefix, pruning rules as defined in [RFC2328] section 16.4.1
are applied. The alternate ASBRs pruned using above rules are not are applied. The alternate ASBRs pruned using above rules are not
considered for LFA evaluation. considered for LFA evaluation.
4.2.3. Type 1 and Type 2 costs 4.2.1.2. Type 1 and Type 2 costs
If there are multiple ASBRs not pruned via rules defined in If there are multiple ASBRs not pruned via rules defined in
Section 4.2.2, the cost type advertised by the ASBRs is compared. Section 4.2.1.1, the cost type advertised by the ASBRs is compared.
ASBRs advertising Type1 costs are preferred and the type2 costs are ASBRs advertising type 1 costs are preferred and the type 2 costs are
pruned. If two ASBRs advertise same type2 cost, the alternate ASBRs pruned. If two ASBRs advertise same type 2 cost, the alternate ASBRs
are considered along with their type1 cost for evaluation. If the are considered along with their cost to reach ASBR/forwarding adress
two ASBRs with same type2 as well as type1 cost, ECMP FRR is for evaluation. If the two ASBRs have same type 2 cost as well as
programmed. If there are two ASBRs with different type2 cost, the same cost to reach ASBR, ECMP FRR is programmed. When there are
higher cost ASBR is pruned. The inequalities for evaluating multiple ASBRs advertising same type 2 cost for the prefix, primary
AS external route calculation as described in [RFC2328] section
16.4.1 selects the route with lowest type 2 cost. ASBRs advertising
different type 2 cost (higher cost) are not considered for LFA
evaluation. Alternate ASBRs advertising type 2 cost for the prefix
but are not chosen as primary due to higher cost to reach ASBR are
considered for LFA evaluation.The inequalities for evaluating
alternate ASBR for type 1 and type 2 costs are same, as the alternate alternate ASBR for type 1 and type 2 costs are same, as the alternate
ASBRs with different type2 costs are pruned and the evaluation is ASBRs with different type 2 costs are pruned and the evaluation is
based on equal type 2 cost ASBRS. based on equal type 2 cost ASBRS.
4.2.4. RFC1583compatibility is set to enabled 4.2.1.3. RFC1583compatibility is set to enabled
When RFC1583Compatibility is set to enabled, multiple ASBRs belonging When RFC1583Compatibility is set to enabled, multiple ASBRs belonging
to different area advertising same prefix are chosen based on cost to different area advertising same prefix are chosen based on cost
and hence are valid alternate ASBRs for the LFA evaluation. and hence are valid alternate ASBRs for the LFA evaluation. The
inequalities described in Section 4.2.2 are applicable based on
forwarding address and cost type advertised in External LSA.
4.2.5. Type 7 routes 4.2.1.4. Type 7 routes
Type 5 routes always get preference over Type 7 and the alternate Type 5 routes always get preference over Type 7 and the alternate
ASBRs chosen for LFA calculation should belong to same type. Among ASBRs chosen for LFA calculation should belong to same type. Among
Type 7 routes, routes with p-bit and forwarding address set have Type 7 routes, routes with p-bit and forwarding address set have
higher preference than routes without these attributes. Alternate higher preference than routes without these attributes. Alternate
ASBRs selected for LFA comparison should have same p-bit and ASBRs selected for LFA comparison should have same p-bit and
forwarding address attributes. forwarding address attributes.
4.2.6. Inequalities to be applied for alternate ASBR selection 4.2.2. Inequalities to be applied for alternate ASBR selection
The alternate ASBRs selected using above mechanism described in The alternate ASBRs selected using above mechanism described in
Section 4.2.1, are evaluated for Loop free criteria using below Section 4.2.1, are evaluated for Loop free criteria using below
inequalities. inequalities.
4.2.6.1. Forwarding address set to non-zero value 4.2.2.1. Forwarding address set to non-zero value
Link-Protection: Link-Protection:
F_opt(N,PO_i)+ cost(PO_i,P) < D_opt(N,S) + F_opt(N,PO_i)+ cost(PO_i,P) < D_opt(N,S) +
F_opt(S,PO_best) + cost(PO_best,P) F_opt(S,PO_best) + cost(PO_best,P)
Link-Protection + Downstream-paths-only: Link-Protection + Downstream-paths-only:
F_opt(N,PO_i)+ cost(PO_i,P) < F_opt(S,PO_best) + cost(PO_best,P) F_opt(N,PO_i)+ cost(PO_i,P) < F_opt(S,PO_best) + cost(PO_best,P)
Node-Protection: Node-Protection:
F_opt(N,PO_i)+ cost(PO_i,P) < D_opt(N,E) + F_opt(N,PO_i)+ cost(PO_i,P) < D_opt(N,E) +
F_opt(E,PO_best) + cost(PO_best,P) F_opt(E,PO_best) + cost(PO_best,P)
Where, Where,
P - The multi-homed prefix being evaluated for
computing alternates
S - The computing router S - The computing router
N - The alternate router being evaluated N - The alternate router being evaluated
E - The primary next-hop on shortest path from S to E - The primary next-hop on shortest path from S to
prefix P. prefix P.
PO_i - The specific prefix-originating router being PO_i - The specific prefix-originating router being
evaluated. evaluated.
PO_best - The prefix-originating router on the shortest path PO_best - The prefix-originating router on the shortest path
from the computing router S to prefix P. from the computing router S to prefix P.
cost(X,Y) - External cost for Y as advertised by X cost(X,Y) - External cost for Y as advertised by X
F_opt(X,Y) - Distance on the shortest path from node X to Forwarding F_opt(X,Y) - Distance on the shortest path from node X to Forwarding
address specified by ASBR Y. address specified by ASBR Y.
D_opt(X,Y) - Distance on the shortest path from node X to node Y. D_opt(X,Y) - Distance on the shortest path from node X to node Y.
Figure 6: LFA inequality definition when forwarding address is non- Figure 6: LFA inequality definition when forwarding address is non-
zero zero
4.2.6.2. ASBRs advertising type1 and type2 cost 4.2.2.2. ASBRs advertising type1 and type2 cost
Link-Protection: Link-Protection:
D_opt(N,PO_i)+ cost(PO_i,P) < D_opt(N,S) + D_opt(N,PO_i)+ cost(PO_i,P) < D_opt(N,S) +
D_opt(S,PO_best) + cost(PO_best,P) D_opt(S,PO_best) + cost(PO_best,P)
Link-Protection + Downstream-paths-only: Link-Protection + Downstream-paths-only:
D_opt(N,PO_i)+ cost(PO_i,P) < D_opt(S,PO_best) + cost(PO_best,P) D_opt(N,PO_i)+ cost(PO_i,P) < D_opt(S,PO_best) + cost(PO_best,P)
Node-Protection: Node-Protection:
D_opt(N,PO_i)+ cost(PO_i,P) < D_opt(N,E) + D_opt(N,PO_i)+ cost(PO_i,P) < D_opt(N,E) +
D_opt(E,PO_best) + cost(PO_best,P) D_opt(E,PO_best) + cost(PO_best,P)
Where, Where,
P - The multi-homed prefix being evaluated for
computing alternates
S - The computing router S - The computing router
N - The alternate router being evaluated N - The alternate router being evaluated
E - The primary next-hop on shortest path from S to E - The primary next-hop on shortest path from S to
prefix P. prefix P.
PO_i - The specific prefix-originating router being PO_i - The specific prefix-originating router being
evaluated. evaluated.
PO_best - The prefix-originating router on the shortest path PO_best - The prefix-originating router on the shortest path
from the computing router S to prefix P. from the computing router S to prefix P.
cost(X,Y) - External cost for Y as advertised by X. cost(X,Y) - External cost for Y as advertised by X.
D_opt(X,Y) - Distance on the shortest path from node X to node Y. D_opt(X,Y) - Distance on the shortest path from node X to node Y.
Figure 7: LFA inequality definition for type1 and type 2 cost Figure 7: LFA inequality definition for type1 and type 2 cost
5. LFA Extended Procedures 5. LFA Extended Procedures
This section explains the additional considerations in various This section explains the additional considerations in various
aspects as listed below to the base LFA specification [RFC5286]. aspects as listed below to the base LFA specification [RFC5286].
5.1. Links with IGP MAX_METRIC 5.1. Links with IGP MAX_METRIC
Section 3.5 and 3.6 of [RFC5286] describes procedures for excluding Section 3.5 and 3.6 of [RFC5286] describe procedures for excluding
nodes and links from use in alternate paths based on the maximum link nodes and links from use in alternate paths based on the maximum link
metric (as defined in for IS-IS in [RFC5305] or as defined in metric (as defined for IS-IS in [RFC5305] or as defined in [RFC6987]
[RFC6987] for OSPF). If these procedures are strictly followed, for OSPF). If these procedures are strictly followed, there are
there are situations, as described below, where the only potential situations, as described below, where the only potential alternate
alternate available which satisfies the basic loop-free condition available which satisfies the basic loop-free condition will not be
will not be considered as alternative. considered as alternative.
+---+ 10 +---+ 10 +---+ +---+ 10 +---+ 10 +---+
| S |------|N1 |-----|D1 | | S |------|N1 |-----|D1 |
+---+ +---+ +---+ +---+ +---+ +---+
| | | |
10 | 10 | 10 | 10 |
|MAX_MET(N2 to S) | |MAX_MET(N2 to S) |
| | | |
| +---+ | | +---+ |
+-------|N2 |--------+ +-------|N2 |--------+
skipping to change at page 14, line 33 skipping to change at page 13, line 33
in both directions, except for the link between S and N2. The S-N2 in both directions, except for the link between S and N2. The S-N2
link has a cost of 10 in the forward direction i.e., from S to N2, link has a cost of 10 in the forward direction i.e., from S to N2,
and a cost of MAX_METRIC (0xffffff /2^24 - 1 for IS-IS and 0xffff for and a cost of MAX_METRIC (0xffffff /2^24 - 1 for IS-IS and 0xffff for
OSPF) in the reverse direction i.e., from N2 to S for a specific end- OSPF) in the reverse direction i.e., from N2 to S for a specific end-
to-end Traffic Engineering (TE) requirement of the operator. At node to-end Traffic Engineering (TE) requirement of the operator. At node
S, D1 is reachable through N1 with cost 20, and D2 is reachable S, D1 is reachable through N1 with cost 20, and D2 is reachable
through N2 with cost 20. Even though neighbor N2 satisfies basic through N2 with cost 20. Even though neighbor N2 satisfies basic
loop-free condition (inequality 1 of [RFC5286]) for D1, S's neighbor loop-free condition (inequality 1 of [RFC5286]) for D1, S's neighbor
N2 could be excluded as a potential alternative because of the N2 could be excluded as a potential alternative because of the
current exclusions as specified in section 3.5 and 3.6 procedure of current exclusions as specified in section 3.5 and 3.6 procedure of
[RFC5286]. But, as the primary traffic destined to D2 continue to [RFC5286]. But, as the primary traffic destined to D2 continues to
use the link and hence irrespective of the reverse metric in this use the link and hence irrespective of the reverse metric in this
case, same link MAY be used as a potential LFA for D1. case, same link MAY be used as a potential LFA for D1.
Alternatively, reverse metric of the link MAY be configured with Alternatively, reverse metric of the link MAY be configured with
MAX_METRIC-1, so that the link can be used as an alternative while MAX_METRIC-1, so that the link can be used as an alternative while
meeting the operator's TE requirements and without having to update meeting the operator's TE requirements and without having to update
the router to fix this particular issue. the router to fix this particular issue.
5.2. Multi Topology Considerations 5.2. Multi Topology Considerations
Section 6.2 and 6.3.2 of [RFC5286] state that multi-topology OSPF and Section 6.2 and 6.3.2 of [RFC5286] state that multi-topology OSPF and
ISIS are out of scope for that specification. This memo clarifies IS-IS are out of scope for that specification. This memo clarifies
and describes the applicability. and describes the applicability.
In Multi Topology (MT) IGP deployments, for each MT ID, a separate In Multi Topology (MT) IGP deployments, for each MT ID, a separate
shortest path tree (SPT) is built with topology specific adjacencies, shortest path tree (SPT) is built with topology specific adjacencies,
the LFA principles laid out in [RFC5286] are actually applicable for the LFA principles laid out in [RFC5286] are actually applicable for
MT IS-IS [RFC5120] LFA SPF. The primary difference in this case is, MT IS-IS [RFC5120] LFA SPF. The primary difference in this case is,
identifying the eligible-set of neighbors for each LFA computation identifying the eligible-set of neighbors for each LFA computation
which is done per MT ID. The eligible-set for each MT ID is which is done per MT ID. The eligible-set for each MT ID is
determined by the presence of IGP adjacency from Source to the determined by the presence of IGP adjacency from Source to the
neighboring node on that MT-ID apart from the administrative neighboring node on that MT-ID apart from the administrative
restrictions and other checks laid out in [RFC5286]. The same is restrictions and other checks laid out in [RFC5286]. The same is
also applicable for MT-OSPF [RFC4915] or different AFs in multi also applicable for MT-OSPF [RFC4915] or different AFs in multi
instance OSPFv3 [RFC5838]. instance OSPFv3 [RFC5838].
However for MT IS-IS, if a "standard topology" is used with MT-ID #0 However for MT IS-IS, if a "standard topology" is used with MT-ID #0
[RFC5286] and both IPv4 [RFC5305] and IPv6 routes/AFs [RFC5308] are [RFC5286] and both IPv4 [RFC5305] and IPv6 routes/AFs [RFC5308] are
present, then the condition of network congruency is applicable for present, then the condition of network congruency is applicable for
LFA computation as well. Network congruency here refers to, having LFA computation as well. Network congruency here refers to, having
same address families provisioned on all the links and all the nodes same address families provisioned on all the links and all the nodes
of the network with MT-ID #0. Here with single decision process both of the network with MT-ID #0. Here with single decision process both
IPv4 and IPv6 next-hops are computed for all the prefixes in the IPv4 and IPv6 next-hops are computed for all the prefixes in the
network and similarly with one LFA computation from all eligible network and similarly with one LFA computation from all eligible
neighbors per [RFC5286], all potential alternatives can be computed. neighbors per [RFC5286], all potential alternatives can be computed.
6. IANA Considerations 6. IANA Considerations
skipping to change at page 16, line 7 skipping to change at page 15, line 7
Email: cbowers@juniper.ne Email: cbowers@juniper.ne
Bruno Decraene Bruno Decraene
Orange, Orange,
France France
Email: bruno.decraene@orange.com Email: bruno.decraene@orange.com
9. Security Considerations 9. Security Considerations
This document does not introduce any change in any of the protocol Existing OSPF security considerations and stronger authentication and
[RFC1195] [RFC5120] [RFC2328] [RFC5838] specifications discussed here manual key management mechanisms are specified in [RFC7474] SHOULD be
and also this does not introduce any new security issues other than considered for OSPF deployments. Security concerns for IS-IS are
as noted in the LFA base specification [RFC5286]. addressed in [RFC5304] and [RFC5310]. Further security analysis for
IS-IS protocol is done in [RFC7645] SHOULD be considered for IS-IS
deployments. This document does not introduce any change in any of
the protocol [RFC1195] [RFC5120] [RFC2328] [RFC5838] specifications
discussed here and also this does not introduce any new security
issues other than as noted in the LFA base specification [RFC5286].
10. References 10. References
10.1. Normative References 10.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC5286] Atlas, A., Ed. and A. Zinin, Ed., "Basic Specification for [RFC5286] Atlas, A., Ed. and A. Zinin, Ed., "Basic Specification for
IP Fast Reroute: Loop-Free Alternates", RFC 5286, IP Fast Reroute: Loop-Free Alternates", RFC 5286,
DOI 10.17487/RFC5286, September 2008, DOI 10.17487/RFC5286, September 2008,
<https://www.rfc-editor.org/info/rfc5286>. <https://www.rfc-editor.org/info/rfc5286>.
[RFC5714] Shand, M. and S. Bryant, "IP Fast Reroute Framework",
RFC 5714, DOI 10.17487/RFC5714, January 2010,
<https://www.rfc-editor.org/info/rfc5714>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
10.2. Informative References 10.2. Informative References
[RFC1195] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and [RFC1195] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and
dual environments", RFC 1195, DOI 10.17487/RFC1195, dual environments", RFC 1195, DOI 10.17487/RFC1195,
December 1990, <https://www.rfc-editor.org/info/rfc1195>. December 1990, <https://www.rfc-editor.org/info/rfc1195>.
[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>.
skipping to change at page 16, line 47 skipping to change at page 16, line 11
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>.
[RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi [RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi
Topology (MT) Routing in Intermediate System to Topology (MT) Routing in Intermediate System to
Intermediate Systems (IS-ISs)", RFC 5120, Intermediate Systems (IS-ISs)", RFC 5120,
DOI 10.17487/RFC5120, February 2008, DOI 10.17487/RFC5120, February 2008,
<https://www.rfc-editor.org/info/rfc5120>. <https://www.rfc-editor.org/info/rfc5120>.
[RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic
Authentication", RFC 5304, DOI 10.17487/RFC5304, October
2008, <https://www.rfc-editor.org/info/rfc5304>.
[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, <https://www.rfc-editor.org/info/rfc5305>. 2008, <https://www.rfc-editor.org/info/rfc5305>.
[RFC5308] Hopps, C., "Routing IPv6 with IS-IS", RFC 5308, [RFC5308] Hopps, C., "Routing IPv6 with IS-IS", RFC 5308,
DOI 10.17487/RFC5308, October 2008, DOI 10.17487/RFC5308, October 2008,
<https://www.rfc-editor.org/info/rfc5308>. <https://www.rfc-editor.org/info/rfc5308>.
[RFC5310] Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R.,
and M. Fanto, "IS-IS Generic Cryptographic
Authentication", RFC 5310, DOI 10.17487/RFC5310, February
2009, <https://www.rfc-editor.org/info/rfc5310>.
[RFC5838] Lindem, A., Ed., Mirtorabi, S., Roy, A., Barnes, M., and [RFC5838] Lindem, A., Ed., Mirtorabi, S., Roy, A., Barnes, M., and
R. Aggarwal, "Support of Address Families in OSPFv3", R. Aggarwal, "Support of Address Families in OSPFv3",
RFC 5838, DOI 10.17487/RFC5838, April 2010, RFC 5838, DOI 10.17487/RFC5838, April 2010,
<https://www.rfc-editor.org/info/rfc5838>. <https://www.rfc-editor.org/info/rfc5838>.
[RFC6987] Retana, A., Nguyen, L., Zinin, A., White, R., and D. [RFC6987] Retana, A., Nguyen, L., Zinin, A., White, R., and D.
McPherson, "OSPF Stub Router Advertisement", RFC 6987, McPherson, "OSPF Stub Router Advertisement", RFC 6987,
DOI 10.17487/RFC6987, September 2013, DOI 10.17487/RFC6987, September 2013,
<https://www.rfc-editor.org/info/rfc6987>. <https://www.rfc-editor.org/info/rfc6987>.
Authors' Addresses [RFC7474] Bhatia, M., Hartman, S., Zhang, D., and A. Lindem, Ed.,
"Security Extension for OSPFv2 When Using Manual Key
Management", RFC 7474, DOI 10.17487/RFC7474, April 2015,
<https://www.rfc-editor.org/info/rfc7474>.
[RFC7645] Chunduri, U., Tian, A., and W. Lu, "The Keying and
Authentication for Routing Protocol (KARP) IS-IS Security
Analysis", RFC 7645, DOI 10.17487/RFC7645, September 2015,
<https://www.rfc-editor.org/info/rfc7645>.
Authors' Addresses
Pushpasis Sarkar (editor) Pushpasis Sarkar (editor)
Arrcus, Inc. Arrcus, Inc.
Email: pushpasis.ietf@gmail.com Email: pushpasis.ietf@gmail.com
Shraddha Hegde
Juniper Networks, Inc.
Electra, Exora Business Park
Bangalore, KA 560103
India
Email: shraddha@juniper.net
Uma Chunduri (editor) Uma Chunduri (editor)
Huawei USA Huawei USA
2330 Central Expressway 2330 Central Expressway
Santa Clara, CA 95050 Santa Clara, CA 95050
USA USA
Email: uma.chunduri@huawei.com Email: uma.chunduri@huawei.com
Shraddha Hegde
Juniper Networks, Inc.
Electra, Exora Business Park
Bangalore, KA 560103
India
Email: shraddha@juniper.net
Jeff Tantsura Jeff Tantsura
Nuage Networks Nuage Networks
755 Ravendale Drive 755 Ravendale Drive
Mountain View, CA 94043 Mountain View, CA 94043
USA USA
Email: jefftant.ietf@gmail.com Email: jefftant.ietf@gmail.com
Hannes Gredler Hannes Gredler
RtBrick, Inc. RtBrick, Inc.
Email: hannes@rtbrick.com Email: hannes@rtbrick.com
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