Network Working Group Z. Li
Internet-Draft N. Wu
Intended status: Standards Track Q. Zhao
Expires: January 5, 2015 Huawei Technologies
A. Atlas
C. Bowers
Juniper Networks
J. Tantsura
Ericsson
July 4, 2014
Intermediate System to Intermediate System (IS-IS) Extensions for
Maximally Redundant Trees (MRT)
draft-li-isis-mrt-01
Abstract
This document describes necessary extensions to IS-IS to support the
distributed computation of Maximally Redundant Trees (MRT). Some
example uses of the MRTs include IP/LDP Fast-Reroute and global
protection or live-live for multicast traffic. The extensions
indicate what MRT profile(s) each router supports. Different MRT
profiles can be defined to support different uses and to allow
transition of capabilities. An extension is introduced to flood MRT-
Ineligible links, due to administrative policy.
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 January 5, 2015.
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Copyright Notice
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document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Using MRT with Multi-Topology IGP Routing . . . . . . . . . . 4
5. Overview of IS-IS Signaling Extensions for MRT . . . . . . . 5
5.1. Supporting MRT Profiles . . . . . . . . . . . . . . . . . 6
5.2. Electing GADAG Root . . . . . . . . . . . . . . . . . . . 6
5.3. Advertising MRT-Ineligible Links for MRT . . . . . . . . 7
5.4. Triggering an MRT Computation . . . . . . . . . . . . . . 7
6. MRT Capability Advertisement . . . . . . . . . . . . . . . . 7
6.1. Advertising MRT Capability in IS-IS LSP . . . . . . . . . 7
6.2. MRT Profile sub-TLV in IS-IS Router CAPABILITY TLV . . . 8
6.3. MRT-Ineligible Links sub-TLV in IS-IS Router CAPABILITY
TLV . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
7. Controlled Convergence sub-TLV in IS-IS Router CAPABILITY TLV 10
8. Handling MRT Capability Sending and Receiving . . . . . . . . 11
8.1. Advertising MRT extension . . . . . . . . . . . . . . . . 12
8.2. Parsing MRT extension . . . . . . . . . . . . . . . . . . 12
9. Backwards Compatibility . . . . . . . . . . . . . . . . . . . 12
10. Implementation Status . . . . . . . . . . . . . . . . . . . . 13
11. Security Considerations . . . . . . . . . . . . . . . . . . . 13
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
13.1. Normative References . . . . . . . . . . . . . . . . . . 13
13.2. Infomative References . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
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1. Introduction
The IS-IS protocol is specified in [ISO10589], with extensions for
supporting IPv4 and IPv6 specified in [RFC1195] and [RFC5308]. Each
Intermediate System (IS) (router) advertises one or more IS-IS Link
State Protocol Data Units (LSPs) with routing information. Each LSP
is composed of a fixed header and a number of tuples, each consisting
of a Type, a Length, and a Value. Such tuples are commonly known as
TLVs, and are a good way of encoding information in a flexible and
extensible format.
[I-D.ietf-rtgwg-mrt-frr-architecture] gives a complete solution for
IP/LDP fast-reroute using Maximally Redundant Trees (MRT) to provide
alternates. This document describes the necessary signaling
extensions for supporting MRT-FRR used in IS-IS routing domain.
2. Requirements Language
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 [RFC2119].
3. Terminology
Redundant Trees (RT): A pair of trees where the path from any node X
to the root R along the first tree is node-disjoint with the path
from the same node X to the root R along the second tree. These can
be computed in 2-connected graphs.
Maximally Redundant Trees (MRT): A pair of trees where the path from
any node X to the root R along the first tree and the path from the
same node X to the root R along the second tree share the minimum
number of nodes and the minimum number of links. Each such shared
node is a cut-vertex. Any shared links are cut-links. Any RT is an
MRT but many MRTs are not RTs.
MRT Island: From the computing router, the set of routers that
support a particular MRT profile and are connected via MRT- eligible
links.
GADAG: Generalized Almost Directed Acyclic Graph - a graph which is
the combination of the ADAGs of all blocks. Transforming a network
graph into a GADAG is part of the MRT algorithm.
MRT-Red: MRT-Red is used to describe one of the two MRTs; it is used
to describe the associated forwarding topology and MT-ID.
Specifically, MRT-Red is the decreasing MRT where links in the GADAG
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are taken in the direction from a higher topologically ordered node
to a lower one.
MRT-Blue: MRT-Blue is used to describe one of the two MRTs; it is
used to describe the associated forwarding topology and MT-ID.
Specifically, MRT-Blue is the increasing MRT where links in the GADAG
are taken in the direction from a lower topologically ordered node to
a higher one.
4. Using MRT with Multi-Topology IGP Routing
Both IS-IS and OSPF have support for multi-topology routing (see
[RFC5120] for ISIS and [RFC4915] for OSPF.) In addition to the
standard topology (identified by MT-ID=0), these extensions allow the
IGP to identify particular links and nodes as participating in
additional topologies (identified by MT-ID!=0). A given link can
belong to several topologies and be assigned different metrics in
each topology. The IGP runs an independent SPF computation for each
topology, finding independent shortest paths to prefixes in each
topology.
It is straightforward to extend the MRT computations to multi-
topology IGP routing. For each IGP topology identified by an IGP MT-
ID, we need to identify the node and links belonging to an MRT Island
for that IGP MT-ID. This process creates a graph for the MRT Island
for that specific IGP MT-ID, which can then be used to compute the
transit next-hops and alternate next-hops for MRT-Red and MRT-Blue
for that specific IGP MT-ID.
We expect that initial implementation and deployments of MRT will be
primarily concerned with computing MRT-Red and Blue trees for the
standard topology (IGP MT-ID=0). However, we have chosen to specify
the IS-IS MRT extensions to accommodate the computation of MRT-Red
and MRT-Blue in a multi-topology IS-IS environment. This comes at
the expense of 2-6 octets per TLV for MT-ID values, but it will allow
for standards-based multi-topology aware MRT implementations for ISIS
without any future standards work.
Using MRT in a multi-topology IGP environment does have one
complication which should be discussed. Forwarding LDP traffic over
MRT paths in the standard IGP topology requires the use of labels
bound to topology-scoped FECs to identify traffic on MRT-Red and Blue
trees. This is described in Section 6 of
[I-D.ietf-rtgwg-mrt-frr-architecture]. To facilitate this, an MRT
profile specifies IANA-assigned MRT-Red and MRT-Blue LDP MT-ID
values, which are then used by LDP to advertise labels for the MRT-
Red and Blue forwarding topologies. Note that the MRT-Red and MRT-
Blue LDP MT-ID values assigned by IANA for a given MRT profile
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correspond to the MRT-Red and Blue forwarding trees associated with
the standard IGP topology with IGP MT-ID=0. For example, suppose
that a future MRT profile X is assigned (hypothetical) MRT-Red and
MRT-Blue LDP MT-ID values of 2001 and 2002. Then labels for shortest
path forwarding trees associated with the standard IGP topology will
be advertised using FECs with MT-ID=0, while the labels for the MRT-
Red and Blue forwarding trees for profile X will be advertised using
FECS with MT-ID=2001 and 2002, respectively. In the absence of
multi-topology IGP routing, all MT-IDs used by LDP for MRT are
assigned by IANA, so there are no potential conflicts in LDP MT-ID
usage.
When MRT is used together with multi-topology IGP routing, additional
LDP MT-IDs need to be specified for carrying traffic on the MRT-Red
and Blue forwarding trees associated with the additional IGP routing
topologies. Building on the previous example, suppose that a network
is configured with an additional IGP routing topology using MT-ID=20,
in addition to the standard topology with MT-ID=0. The router
advertises support for MRT with respect to MT-ID=20 with profile X,
as well as support for MRT with respect to MT-ID=0 with profile X.
The MRT-Red and Blue LDP MT-IDs for MT-ID=0 with profile X are still
inherited from profile X, as in the previous example. In order to
use LDP to create the MRT-Red and Blue forwarding trees for the IGP
topology with MT-ID=20, the router could, for example, advertise MRT-
Red and MRT-Blue LDP MT-ID values of 21 and 22 for IGP MT-ID=20 and
profile X. This overrides the (hypothetical) IANA-assigned values
MRT-Red and MRT-Blue LDP MT-ID values for profile X, but maintains
all other properties of profile X. Care must be taken to avoid
advertising LDP MT-ID values that conflict with implicitly advertised
IANA-assigned values LDP MT-ID.
The semantics of the IS-IS MRT extensions in this document are
designed to handle the most common case (MRT in the absence of multi-
topology IGP routing) in a simple manner. Setting the IGP MT-ID
field as well as the MRT-Blue and MRT-Red LDP MT-ID fields to 0 in
the TLV and sub-TLVs in this document results in the desired behavior
for the standard IGP topology.
5. Overview of IS-IS Signaling Extensions for MRT
As stated in [I-D.ietf-rtgwg-mrt-frr-algorithm], it is necessary for
each MRT-Capable router to compute MRT next hops in a consistent
fashion. This is achieved by using same MRT profile and selecting
the unique root in a MRT Island which is connected by MRT-Eligible
links. Each of these issues will be discussed in following sections
separately.
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5.1. Supporting MRT Profiles
The contents and requirements of an MRT profile has been defined in
[I-D.ietf-rtgwg-mrt-frr-architecture]. The parameters and behavioral
rules contained in an MRT profile define one router's MRT
capabilities. Based on common capabilities, one unified MRT Island
is built.
The MRT-Capable router MUST advertise its corresponding MRT profiles
by IS-IS protocol extension within IS-IS routing domain. The
capabilities of advertiser MUST conform to the profile it claimed
completely, especially the MT-IDs, the algorithm and the
corresponding forwarding mechanism. This advertisement MUST have
level scope. One router MAY support multiple MRT profiles and it
MUST advertise these profiles in corresponding IS-IS level. The MT-
IDs used in one supported MRT Profile MUST NOT overlap with those MT-
IDs used in a different supported MRT Profile.
The default MRT Profile is defined in
[I-D.ietf-rtgwg-mrt-frr-architecture]. Its behavior is intended to
support IP/LDP unicast and multicast Fast-Reroute. MRT-Capable
routers SHOULD support the default MRT profile.
5.2. Electing GADAG Root
As per [I-D.ietf-rtgwg-mrt-frr-algorithm], a GADAG root MUST be
selected for one MRT Island. An unique GADAG root in common-sense
among MRT Island routers is a necessity to do MRT computation. Since
the selection of the GADAG root can affect the alternates and the
traffic through it, the selection rules give network operator a knob
to control the alternates and the traffic inside the MRT Island.
Relevant discussion for the relationship between GADAG root role and
MRT Island alternates is out of the scope of this document.
Each MRT-Capable router MUST advertise its priority for GADAG root
selection. One router can only have one priority in the same MRT
Island. It can have multiple priorities for different MRT Islands it
supports. Routers that are marked as overloaded([RFC3787]) are not
qualified as candidate for root selection.
The GADAG Root Selection Policy (defined as part of an MRT profile)
may make use of the GADAG Root Selection Priority value advertised in
the MRT Profile in the IS-IS Router CAPABILITY TLV. For example, the
GADAG Root Selection Policy for the default MRT profile is the
following: Among the routers in the MRT Island and with the highest
priority advertised, an implementation MUST pick the router with the
highest Router ID to be the GADAG root.
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When the current root is out of service or new router with higher
priority joined into the MRT Island, the GADAG root MUST be re-
selected. A new MRT computation will be triggered because of such a
topology change.
5.3. Advertising MRT-Ineligible Links for MRT
For certain administrative or management reason, some links may not
be involved into MRT computation. In this scenario, MRT-Capable
router MUST claim those MRT-Ineligible links are out of MRT Island
scope. If such claim splits current MRT Island then MRT computation
has to be done inside the modified MRT Island which the computing
router belongs to.
5.4. Triggering an MRT Computation
A MRT Computation can be triggered through topology changes or MRT
capability changes of any router in the MRT Island. It is always
triggered for a given MRT Profile in the corresponding level. First,
the associated MRT Island is determined. Then, the GADAG Root is
selected. Finally, the actual MRT algorithm is run to compute the
transit MRT-Red and MRT-Blue topologies. Additionally, the router
MAY choose to compute MRT-FRR alternates or make other use of the MRT
computation results.
Prefixes can be attached and detached and have their associated MRT-
Red and MRT-Blue next-hops computed without requiring a new MRT
computation.
6. MRT Capability Advertisement
MRT-Capable router MUST identify its MRT capabilities through IS-IS
Link State Packet(LSP) in level scope.
6.1. Advertising MRT Capability in IS-IS LSP
One new M-bit is introduced into TLV 229 to identify router is MRT-
Capable. Structure of TLV 229 is stated in [RFC5120] as pictured
below:
TYPE: 229
LENGTH: total length of the value field, it SHOULD be 2 times the
number of MT components.
VALUE: one or more 2-byte MT components, structured as follows:
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No. of Octets
+--------------------------------+
|O |A |M |R | MT ID | 2
+--------------------------------+
Bit M identifies the originator is of MRT-Capable. The MRT-Blue and
the MRT-Red alternates will be calculated for the MT identified by
MT-ID.
This M-bit MUST be set and checked in LSP fragment 0. A MRT-Capable
router MUST advertise this TLV with M-bit set for corresponding MT.
For instance, if M-bit is set for MT-ID #0, MRT alternates will be
calculated for standard topology.
If only M-bit is advertised for MRT-Capabilities without any other
MRT information then the router is regarded as supporting default MRT
profile with default GADAG root selection priority.
6.2. MRT Profile sub-TLV in IS-IS Router CAPABILITY TLV
A new MRT Profile sub-TLV is introduced into IS-IS Router CAPABILITY
TLV[RFC4971] to advertise MRT capabilities. Since MRT is per level
scope, the S-bit and D-bit of IS-IS Router CAPABILITY TLV MUST be set
to zero. The structure of the MRT Profile sub-TLV is pictured as
below:
TYPE: TBA-MRT-ISIS-1 (To Be Allocated by IANA)
LENGTH: 8
VALUE:
MT ID (2 octet with 4 bits reserved)
Profile ID (1 octet)
MRT-Red LDP MT-ID (2 octet)
MRT-Blue LDP MT-ID (2 octet)
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+--------------------------------+
|R |R |R |R | MT ID | 2
+----------------+---------------+
| Profile ID | 1
+----------------+
| GADAG Priority | 1
+----------------+---------------+
| MRT-Red LDP MT-ID | 2
+--------------------------------+
| MRT-Blue LDP MT-ID | 2
+--------------------------------+
12-bit MT ID represents the base MT topology which MRT computation is
based on. Profile ID represents the MRT profile this router supports
and GADAG Root Selection Priority is the priority for root selection.
The range of this priority is [0, 255] with 128 as the default value.
The GADAG Root Selection Policy defined as part of a given MRT
profile determine how the GADAG Root Selection Priority value is
used.
If the MRT-Blue LDP MT-ID is 0, then the value specified in the
associated MRT Profile is assumed. If the MRT-Red LDP MT-ID is 0,
then the value specified in the associated MRT profile is assumed.
The MRT-Blue LDP MT-ID and MRT-Red LDP MT-ID MUST NOT be the reserved
values for LDP MT-IDs ([I-D.ietf-mpls-ldp-multi-topology] ). The
value for MRT-Blue LDP MT-ID and MRT-Red LDP MT-ID MUST be different
except for 0. As stated above, the MRT-Blue LDP MT-ID and MRT-Red
LDP MT-ID MUST NOT overlap among profiles if multiple MRT-Profile
sub-TLVs are advertised.
This sub-TLV can occur multiple times if this router support multiple
MRT profiles. This can happen during transition or to support
multiple uses of MRT which prefer different profiles.
6.3. MRT-Ineligible Links sub-TLV in IS-IS Router CAPABILITY TLV
As a matter of policy, some links may not be available for the MRT
computation, which can prevent alternates or traffic using these
links. For instance, policy can be made to prevent fast-rerouted
traffic from taking those links.
For a link to be excluded from the MRT computation, it MUST be
advertised as sub-TLV in IS-IS Router CAPABILITY TLV which is in
level scope with S-bit and D-bit unset. The MRT-Ineligible Link sub-
TLV is structured as below:
TYPE: TBA-MRT-ISIS-2 (To Be Allocated by IANA)
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LENGTH: from 9 to 255 octets
VALUE:
MT ID (2 octet with 4 bits reserved)
System ID and pseudo-node number (7 octet for each MRT-Ineligible
Link)
No. of Octets
+--------------------------------+
|R |R |R |R | MT ID | 2
+--------------------------------+
|System ID and pseudonode number | 7
+--------------------------------+
| Default metric | 3
+--------------------------------+
. .
. .
+--------------------------------+
|System ID and pseudonode number | 7
+--------------------------------+
| Default metric | 3
+--------------------------------+
Each MRT-Ineligible Link is identified by neighbor's System ID and
pseudo-node number and Default metric, same as IS Reachability TLV.
This sub-TLV MAY occur multiple times if multiple links are
ineligible.
7. Controlled Convergence sub-TLV in IS-IS Router CAPABILITY TLV
Section 12.2 of [I-D.ietf-rtgwg-mrt-frr-architecture] describes the
need to wait for a configured or advertised period after a network
failure to insure that all routers are using their new SPTs.
Similarly, avoiding micro-forwarding loops during convergence
[RFC5715] requires determining the maximum among all routers in the
area of the worst-case route computation and FIB installation time.
More details on the specific reasoning and need for flooding this
value are given in [I-D.atlas-bryant-shand-lf-timers].
A new Controlled Convergence sub-TLV is introduced into the IS-IS
Router CAPABILITY TLV [RFC4971] to advertise the worst-case time for
a router to compute and install all IS-IS routes in the level after a
change to a stable network. This advertisement has per level scope,
so the S-bit and D-bit of IS-IS Router CAPABILITY TLV MUST be set to
zero. The advertisement is scoped by IGP MT-ID, allowing a router
supporting multi-topology IGP routing to advertise a different worst-
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case compute and install time for each IGP topology. This make sense
as the SPF computations for each IGP topology are independent of one
another, and may have different worst-case compute and install times.
The structure of the Controlled Convergence sub-TLV is shown below:
TYPE: TBA-MRT-ISIS-3 (To Be Allocated by IANA)
LENGTH: 3
VALUE:
MT ID (2 octet with 4 bits reserved)
FIB compute/install time (1 octet)
+--------------------------------+
|R |R |R |R | MT ID | 2
+----------------+---------------+
|FIB comp/in time| 1
+----------------+
The FIB compute/install time is the worst-case time the router may
take to compute and install all IS-IS routes in the level after a
change to a stable network. The value is in milliseconds.
The FIB compute/install time value sent by a router SHOULD be an
estimate taking into account network scale or real-time measurements,
or both. Advertisements SHOULD be dampened to avoid frequent
communication of small changes in the FIB compute/install time.
A router receiving the Controlled Convergence sub-TLV SHOULD estimate
the network convergence time as the maximum of the FIB compute/
install times advertised by the routers in a level, including itself.
In order to account for routers that do not advertise the Controlled
Convergence sub-TLV, a router MAY use a locally configured minimum
network convergence time as a lower bound on the computed network
convergence time. A router MAY use a locally configured maximum
network convergence time as an upper bound on the computed network
convergence time.
8. Handling MRT Capability Sending and Receiving
The M-bit which identifies router's MRT capability MUST be advertised
in LSP fragment 0. Those MRT related sub-TLVs SHOULD be ignored when
MRT Capability bit is unset. When changes in MRT capabilities are
received, a MRT computation SHOULD be triggered but MAY be delayed
for a while to allow reception of all MRT-related information.
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8.1. Advertising MRT extension
MRT sub-TLVs are encapsulated in the Router Capability TLV and
advertised through LSP PDU for the level-wide. MRT sub-TLVs are
optional. If one router does not support MRT, it MUST NOT advertise
those sub-TLVs.
Since the advertisement scope of the MRT sub-TLV is level-wide, the
D-Bit and S-Bit of the Router Capability TLV MUST be set as 0 when it
is advertised. If other sub-TLVs in the Router Capability TLV need
different values for those two bits, there MUST be an independent
Router Capability TLV for MRT sub-TLVs.
When MRT related information is changed for the router or existing
IS-IS LSP mechanisms are triggered for refreshing or updating, MRT
sub-TLVs MUST be advertised if the router is MRT-Capable.
For administrative policies or reasons, it may be desirable to
exclude certain links from the MRT computation. MRT-Ineligible sub-
TLV is used to advertise which links should be excluded. Note that
an interface advertised as MRT-Ineligigle by a router is ineligible
with respect to all profiles advertised by that router.
8.2. Parsing MRT extension
MRT extension MUST NOT affect the peer setup and the routing
calculation of the standard topology.
MRT sub-TLVs SHOULD be validated like other sub-TLVs when received.
MRT sub-TLVs SHOULD also be taken for the checksum calculation and
authentication.
If MT-ID conflict is found for MRT-Red or MRT-blue from multiple sub-
TLVs then those associated sub-TLVs MUST be ignored.
Links advertised in MRT-Ineligible sub-TLV MUST be precluded from MRT
Computation. The removal of those links may change the computing
router's MRT Island significantly.
9. Backwards Compatibility
The M-bit for MRT capability, the MRT Profile sub-TLV and the MRT-
Ineligible Link sub-TLV defined in this document SHOULD NOT introduce
any interoperability issues. Routers that do not support these MRT
extensions SHOULD silently ignore them. Alternates or traffic MUST
NOT be affected in current IS-IS routing domain.
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10. Implementation Status
[RFC Editor: please remove this section prior to publication.]
Please see [I-D.ietf-rtgwg-mrt-frr-architecture] for details on
implementation status.
11. Security Considerations
This IS-IS extension is not believed to introduce new security
concerns.
12. IANA Considerations
Please allocate values for the following IS-IS Router CAPABILITY TLV
Types [RFC4971]: MRT Profile sub-TLV (TBA-MRT-ISIS-1), MRT-Ineligible
Link sub-TLV (TBA-MRT-ISIS-2), and Controlled Convergence sub-TLV
(TBA-MRT-ISIS-3).
13. References
13.1. Normative References
[I-D.ietf-mpls-ldp-multi-topology]
Zhao, Q., Raza, K., Zhou, C., Fang, L., Li, L., and D.
King, "LDP Extensions for Multi Topology", draft-ietf-
mpls-ldp-multi-topology-12 (work in progress), April 2014.
[I-D.ietf-rtgwg-mrt-frr-algorithm]
Enyedi, G., Csaszar, A., Atlas, A., Bowers, C., and A.
Gopalan, "Algorithms for computing Maximally Redundant
Trees for IP/LDP Fast-Reroute", draft-rtgwg-mrt-frr-
algorithm-01 (work in progress), July 2014.
[I-D.ietf-rtgwg-mrt-frr-architecture]
Atlas, A., Kebler, R., Bowers, C., Enyedi, G., Csaszar,
A., Tantsura, J., Konstantynowicz, M., and R. White, "An
Architecture for IP/LDP Fast-Reroute Using Maximally
Redundant Trees", draft-rtgwg-mrt-frr-architecture-04
(work in progress), July 2014.
[RFC3137] Retana, A., Nguyen, L., White, R., Zinin, A., and D.
McPherson, "OSPF Stub Router Advertisement", RFC 3137,
June 2001.
[RFC3787] Parker, J., "Recommendations for Interoperable IP Networks
using Intermediate System to Intermediate System (IS-IS)",
RFC 3787, May 2004.
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Internet-Draft IS-IS Extensions for MRT July 2014
13.2. Infomative References
[I-D.atlas-bryant-shand-lf-timers]
K, A. and S. Bryant, "Synchronisation of Loop Free Timer
Values", draft-atlas-bryant-shand-lf-timers-04 (work in
progress), February 2008.
[RFC1195] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and
dual environments", RFC 1195, December 1990.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4915] Psenak, P., Mirtorabi, S., Roy, A., Nguyen, L., and P.
Pillay-Esnault, "Multi-Topology (MT) Routing in OSPF", RFC
4915, June 2007.
[RFC4971] Vasseur, JP., Shen, N., and R. Aggarwal, "Intermediate
System to Intermediate System (IS-IS) Extensions for
Advertising Router Information", RFC 4971, July 2007.
[RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi
Topology (MT) Routing in Intermediate System to
Intermediate Systems (IS-ISs)", RFC 5120, February 2008.
[RFC5308] Hopps, C., "Routing IPv6 with IS-IS", RFC 5308, October
2008.
[RFC5715] Shand, M. and S. Bryant, "A Framework for Loop-Free
Convergence", RFC 5715, January 2010.
Authors' Addresses
Zhenbin Li
Huawei Technologies
Huawei Bld., No.156 Beiqing Rd.
Beijing 100095
China
Email: lizhenbin@huawei.com
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Nan Wu
Huawei Technologies
Huawei Bld., No.156 Beiqing Rd.
Beijing 100095
China
Email: eric.wu@huawei.com
Quintin Zhao
Huawei Technologies
125 Nagog Technology Park
Acton, MA 01719
USA
Alia Atlas
Juniper Networks
10 Technology Park Drive
Westford, MA 01886
USA
Email: akatlas@juniper.net
Chris Bowers
Juniper Networks
1194 N. Mathilda Ave.
Sunnyvale, CA 94089
USA
Email: cbowers@juniper.net
Jeff Tantsura
Ericsson
300 Holger Way
San Jose, CA 95134
USA
Email: jeff.tantsura@ericsson.com
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