Flood Reflectors
draft-przygienda-lsr-flood-reflection-00
The information below is for an old version of the document.
| Document | Type |
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|---|---|---|---|
| Authors | Tony Przygienda , Chris Bowers , Yiu Lee , Alankar Sharma , Russ White | ||
| Last updated | 2019-11-04 (Latest revision 2019-11-03) | ||
| Replaces | draft-przygienda-flood-reflector | ||
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draft-przygienda-lsr-flood-reflection-00
Network Working Group A. Przygienda
Internet-Draft C. Bowers
Intended status: Standards Track Juniper
Expires: May 5, 2020 Y. Lee
A. Sharma
Comcast
R. White
Juniper
November 2, 2019
Flood Reflectors
draft-przygienda-lsr-flood-reflection-00
Abstract
This document provides specification of an optional ISIS extension
that allows to create l2 flood reflector topologies allowing
forwarding through all paths within L1 areas when they are used as
'transit' to guarantee L2 connectivity between L2 'islands'. Only
routers participating in the flood reflection have to be upgraded and
with that the feature allows to significantly increase practical size
of ISIS L2 backbone without forklifting the whole domain or complex
configuration requirements.
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 RFC 2119 [RFC2119].
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 https://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 May 5, 2020.
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Copyright Notice
Copyright (c) 2019 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
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Description . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Further Details . . . . . . . . . . . . . . . . . . . . . . . 6
3. Flood Reflection TLV . . . . . . . . . . . . . . . . . . . . 7
4. Flood Reflection Discovery Sub-TLV . . . . . . . . . . . . . 8
5. Flood Reflector Adjacency Sub-TLV . . . . . . . . . . . . . . 9
6. Procedures . . . . . . . . . . . . . . . . . . . . . . . . . 9
7. Adjacency Forming Procedures . . . . . . . . . . . . . . . . 10
8. Special Considerations . . . . . . . . . . . . . . . . . . . 11
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
9.1. New IS-IS TLV Codepoint . . . . . . . . . . . . . . . . . 12
9.2. Sub TLVs for TLV 242 . . . . . . . . . . . . . . . . . . 12
9.3. Sub TLVs for TLV 22, 23, 25, 141, 222, and 223 . . . . . 12
10. Security Considerations . . . . . . . . . . . . . . . . . . . 12
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
12.1. Informative References . . . . . . . . . . . . . . . . . 13
12.2. Normative References . . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
1. Description
Due to the inherent properties of link-state protocols the number of
IS-IS routers within a flooding domain is limited by processing and
flooding overhead on each node. While that number can be maximized
by well written implementations and techniques such as exponential
back-offs, IS-IS will still reach a saturation point where no further
routers can be added to a single flooding domain. In certain
deployment scenarios of L2 backbones, this limit presents an
obstacle.
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While the standard solution to increase the scale of an IS-IS
deployement is to break it up into multiple L1 flooding domains and a
single L2 backbone, and alternative way is to think about "multiple"
L2 flooding domains connected via L1 flooding domains. In such a
solution, the L2 flooding domains are connected by "L1/L2 lanes"
through the L1 areas to form a single L2 backbone again. However, in
the simplest implementation, this requires the inclusion of most, or
all, of the transit L1 routers as L1/L2 to allow traffic to flow
along optimal paths through such transit areas and with that
ultimately does not help to reduce number of L2 routers and increase
the scalability of L2 backbone.
+----+ +-------+ +-------+ +-------+ +----+
| R1 | | 00 +------------+ 10 +---------------+ 20 | | R4 |
| L2 +--+ L1/L2 | | L1 | | L1/L2 +--+ L2 |
| | | +--------+ +-+ | +------------+ | | |
+----+ ++-+--+-+ | | +---+---+----------+ +-+--+-++ +----+
| | | | | | | | | | | | |
| | | | | | | | | +-----------+ | |
| | +-------+ | | | | | | | | | |
| | | | | | | | | | | +------+ |
| +------+ +--------+ | +-------+ | | |
| | | | | | | | | | | | |
+----+ ++------+---+ | +---+---+---+--+ | +-------+------++ +----+
| R2 | | 01 | | | | | 11 | | | | | 21 | | R5 |
| L2 +--+ L1/L2 +------------+ L1 +---------------+ L1/L2 +--+ L2 |
| | | | | | | | | | | | | | | |
+----+ ++------+---+ | | +---+--++ | +-------+------++ +----+
| | | | | | | | | | | | |
| +---------------+ | | | | | | | |
| | | | | | | | | | | | |
| | +--------------+ | +-----------------+ |
| | | | | | | | | | | | |
+----+ ++-+--+-+ | | +------+---+---+-----+ | | | ++-----++ +----+
| R3 | | 02 | +----------| 12 | | +----+ 22 | | R6 |
| L2 +--+ L1/L2 | +--------| L1 +-------+ | | L1/L2 +--+ L2 |
| | | +------------+ |---------------+ | | |
+----+ +-------+ +-------+-------------+ +-------+ +----+
Figure 1
Figure 1 is an example of a network where a topologically rich L1
area is used to provide transit between six different routers in L2
"partitions" (R1-R6). To take advantage of the cornucopia of paths
in the L1 transit, all the intermediate systems could be placed into
both L1 and L2, but this essentially combines the separate L2
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flooding domains into a single one, triggering again maximum L2 scale
limitation we try to address in first place.
A more effective solution would allow to reduce the number of links
and routers exposed in L2, while still utilizing the full L1 topology
when forwarding through the network.
The mechanism described in [RFC8099] could be used in ISIS to build a
full mesh of tunnels over the L1 transit, but a full mesh of tunnels
can also quickly limit the scaling. The network in Figure 2 would
expose 6 L1/L2 nodes and (5 * 6)/2 = 15 L2 tunnels. In a slightly
larger network, however, in a comparable topology containing 15 L1/L2
edge nodes the number grows very quickly to 105 tunnels.
+----+ +-------+ +-------------------------------+-------+ +----+
| R1 | | 00 | | | 20 | | R4 |
| L2 +--+ L1/L2 +------------------------------------+ L1/L2 +--+ L2 |
| | | | | | | | |
+----+ ++-+-+--+-+ | +-+--+---++ +----+
| | | | | | | |
| +----------------------------------------------+ |
| | | | | | | |
| +-----------------------------------+ | | | |
| | | | | | | |
| +----------------------------------------+ | |
| | | | | | | |
+----+ ++-----+- | | | | -----+-++ +----+
| R2 | | 01 | | | | | | 21 | | R5 |
| L2 +--+ L1/L2 +------------------------------------+ L1/L2 +--+ L2 |
| | | | | | | | | | | |
+----+ ++------+------------------------------+ | | +----+-++ +----+
| | | | | | | |
| | | | | | | |
| +-------------------------------------------+ |
| | | | | | | |
| | | | +----------+ |
| | | | | | | |
| | | | +-----+ | |
| | | | | | | |
+----+ ++----+-+-+ | +-+-+--+-++ +----+
| R3 | | 02 | | | 22 | | R6 |
| L2 +--+ L1/L2 +------------------------------------+ L1/L2 +--+ L2 |
| | | | | | | | |
+----+ +-------+----+ +-------+ +----+
Figure 2
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BGP, as specified in [RFC4271], faced a similar scaling problem,
which has been solved in many networks by deploying BGP route
reflectors [RFC4456]. And, as another crucial observation, BGP route
reflectors do not necessarily have to be in the forwarding path of
the traffic. Such incongruity of forwarding and control path is
allowing conceptually to scale the control plane independently of the
number of nodes participating in the forwarding path.
We propose here a similar solution for IS-IS. A good approximation
of what a "flood reflector" control plane approach would look like is
shown in Figure 3, where router 11 is used as 'reflector.' All L1/L2
routers build an L2 tunnel to such reflectors, so we end up with only
6 L2 tunnels instead of 15 needed for a full mesh. Multiple such
reflectors can be used, of course, allowing the network operator to
balance between resilience, path utilization, and state in the
control plane. The resulting L2 tunnel scale is roughly R * n where
R is the redundancy factor or in other words, number of flood
reflectors used. This compares quite favorably with n^2 / 2 tunnels
used in a fully meshed L2 solution.
+----+ +-------+ +-------+ +----+
| R1 | | 00 | | 20 | | R4 |
| L2 +--+ L1/L2 +--------------+ +-----------------+ L1/L2 +--+ L2 |
| | | | | | | | | |
+----+ +-------+ | | +-------+ +----+
| |
+----+ +-------- --+---+-- --------+ +----+
| R2 | | 01 | | 11 | | 21 | | R5 |
| L2 +--+ L1/L2 +------------+ L1/L2+---------------+ L1/L2 +--+ L2 |
| | | | | FR | | | | |
+----+ +-------+ +-+---+-+ +-------+ +----+
| |
+----+ +-------+ | | +-------+ +----+
| R3 | | 02 +--------------+ +-----------------+ 22 | | R6 |
| L2 +--+ L1/L2 | | L1/L2 +--+ L2 |
| | | | | | | |
+----+ +-------+ +-------+ +----+
Figure 3
And thus, as suggested already by Figure 3, to scale L2 better we
decouple the forwarding plane from the control plane in a first step.
Router 11 can reflood L2 information while the other routers in Level
1 are not visible in Level 2. Without further additions, however,
with such a change all the data traffic will traverse through 11
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creating a bottleneck and disregarding available capacity in the
paths crossing the 'hidden' routers 10 and 12.
To use the whole L1 capacity with flood reflectors, multiple pieces
will be necessary, only one of which is a local protocol extension on
the L1/L2 leafs and the 'flood reflectors'. In first approximation
these extensions include:
o A full mesh of L1 tunnels between the L1/L2 routers, ideally load-
balancing across all available L1 links. This harnesses all
forwarding paths between the L1/L2 edge nodes without injecting
unneeded state into the L2 flooding domain or creating 'choke
points' at the 'flood reflectors' themselves. A solution without
tunnels is also possible by judicious scoping of reachability
information between the levels.
o A 'flood reflector adjacency' for all the adjacencies built for
the purpose of reflecting flooding information. This allows these
'flood reflectors' to participate in the IS-IS control plane
without being used in the forwarding plane. This is a purely
local operation on the L1/L2 ingress; it does not require
replacing or modifying any routers not involved in the reflection
process. Deployment-wise, it is far less tricky to just upgrade
the routers involved in flood reflection rather than have a flag
day on the whole ISIS domain.
o Some way to support reflector redundancy, and potentially some way
to auto-discover and advertise such adjacencies as flood reflector
adjacencies. Such advertisements may allow L2 nodes outside the
L1 to perform optimizations in the future based on this
information.
2. Further Details
Several considerations should be noted in relation to such a flood
reflection mechanism.
First, this allows multi-area IS-IS deployments to scale without any
major modifications in the IS-IS implementation on most of the nodes
deployed in the network. Unmodified (traditional) L2 routers will
compute reachability across the transit L1 area using the flood
reflector adjacencies.
Second, the flood reflectors are not required to participate in
forwarding traffic through the L1 transit area. These flood
reflectors can be hosted on virtual devices outside the forwarding
topology.
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Third, astute readers will realize that flooding reflection may cause
the use of suboptimal paths. This is similar to the BGP route
reflection suboptimal routing problem described in
[ID.draft-ietf-idr-bgp-optimal-route-reflection-19]. The L2
computation determines the egress L1/L2 and with that can create
illusions of ECMP where there is none. And in certain scenarios lead
to an L1/L2 egress which is not globally optimal. This represents a
straightforward instance of the trade-off between the amount of
control plane state and the optimal use of paths through the network
often encountered when aggregating routing information.
One possible solution to this problem is to expose additional
topology information into the L2 flooding domains. In the example
network given, links from router 01 to router 02 can be exposed into
L2 even when 01 and 02 are participating in flood reflection. This
information would allow the L2 nodes to build 'shortcuts' when the L2
flood reflected part of the topology looks more expensive to cross
distance wise.
Another possible variation is for an implementation to approximate
with the L1 tunnel cost the cost of the underlying topology.
Redundancy in the solution is trivial to achieve by building multiple
flood reflectors into the L1 area while all reflectors are still
remaining completely stateless and do not need any kind of
synchronized algorithms amongst themselves except standard ISIS
flooding procedures and database.
3. Flood Reflection TLV
The Flood Reflection TLV is a new top-level TLV that SHOULD appear in
IIHs. The Flood Reflection TLV indicates the flood reflector cluster
(based on Flood Reflector Cluster ID) that a given router interface
is configured to participate in. It also indicates whether the
router is configured to play the role of either flood reflector or
flood reflector client. The Flood Reflector Cluster ID and flood
reflector roles advertised in the IIHs on a given interface are used
to ensure that flood reflector adjacencies are only formed between a
flood reflector and flood reflector client, and that the Flood
Reflector Cluster IDs match. The Flood Reflection TLV has the
following format:
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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 |C| Reserved | FR Cluster ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sub-TLVs ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: TBD
Length: The length, in octets, of the following fields.
C (Client): This bit is set to indicate that the router acts as a
flood reflector client. When this bit is NOT set, the router acts
as a flood reflector.
Flood Reflector Cluster ID: Flood Reflector Cluster Identifier.
This value allows a flood reflector client to establish flood
reflector adjacencies with multiple flood reflectors. Each flood
reflector is the "hub" of a flood reflector cluster. Each flood
reflector cluster is distinguished by a Flood Reflector Cluster
Identifier unique within the IGP domain.
Sub-TLVs: Optional sub-TLVs. For future extensibility, the format
of the Flood Reflection TLV allows for the possibility of
including optional sub-TLVs. No sub-TLVs of the Flood Reflection
TLV are defined in this document.
4. Flood Reflection Discovery Sub-TLV
Flood Reflection Discovery sub-TLV is advertised as a Sub-TLV of the
IS-IS Router Capability TLV-242, defined in [RFC7981]. The Flood
Reflection Discovery sub-TLV is advertised in L1 LSPs with area
flooding scope in order to enable the auto-discovery of flood
reflection capabilities and the automatic creation of L2 tunnels to
be used as flood reflector adjacencies. The Flood Reflection
Discovery sub-TLV has the 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 |C| Reserved | FR Cluster ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: TBD
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Length: The length, in octets, of the following fields.
C (Client): This bit is set to indicate that the router acts as a
flood reflector client. When this bit is NOT set, the router acts
as a flood reflector.
Flood Reflector Cluster ID: The Flood Reflector Cluster Identifier
is the same as that defined in the Flood Reflection TLV.
5. Flood Reflector Adjacency Sub-TLV
The Flood Reflector Adjacency sub-TLV is advertised as a sub-TLV of
TLVs 22, 23, 25, 141, 222, and 223. Its presence indicates that a
given adjacency is a flood reflector adjacency. It is included in L2
area scope flooded LSPs. Flood Reflector Adjacency sub-TLV has the
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 |C| Reserved | FR Cluster ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type: TBD
Length: The length, in octets, of the following fields.
C (Client): This bit is set to indicate that the router advertising
this adjacency is a flood reflector client. When this bit is NOT
set, the router advertising this adjacency is a flood reflector.
Flood Reflector Cluster ID: The Flood Reflector Cluster Identifier
is the same as that defined in the Flood Reflection TLV.
6. Procedures
There are a number of points to consider when implementing and
deploying flood reflection, including:
A router participating in flood reflection MUST be configured as
L1L2 router. It originates the Flood Reflection Discovery sub-TLV
with area flooding scope in L1 only. Normally routers on the edge
of the area, i.e. with non-Flood Reflector L2 adjacencies, will
advertise themselves as clients. Any L1L2 non-client router in
the area can act as flood reflector.
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A flood reflector can participate in a single cluster only, the
clients are free to participate in multiple clusters at the same
time.
Upon reception of Flood Reflection Discovery sub-TLVs, a router
acting as flood reflector client MUST initiate a tunnel towards
each flood reflector with which it shares an Flood Reflector
Cluster ID. The L2 adjacencies formed over such tunnels MUST be
marked as flood reflector adjacencies. If the client has a direct
L2 adjacency with the flood reflector it SHOULD use it instead of
instantiating a new tunnel.
Upon reception of Flood Reflection Discover TLVs, a router acting
as a flood reflector client (in case it doesn't have such direct
L1 adjacencies already) SHOULD initialize tunnels towards all the
other clients in its clusters. L1 *only* adjacencies SHOULD be
built over such tunnels to ensure their liveliness, but other
means can be used (since those adjacencies are used for L1
forwarding, it is prudent to advertise them into L1 as forwarding
links).
On the reflection client, after L2 and L1 computation, all flood
reflector adjacencies used as next-hops for L2 routes MUST be
examined and replaced with the correct L1 tunnel next-hop to the
egress. Alternately, if the ingress has adequate reachability
information to ensure forwarding towards destination via L1
routes, L2 routes using flood reflector adjacencies as next-hops
can be omitted entirely. Due to the rules in Section 7 the
computation in the resulting topology is relatively simple, the L2
SPF from a flood reflector client is guaranteed to reach within a
hop the Flood Reflector and in the following hop the L2 egress to
which it has a L1 forwarding tunnel. However, if the topology has
L2 paths which are not route reflected and look "shorter" than the
path through the Flood Reflector then the computation will have to
track the egress out of the L1 domain by a more advanced
algorithm.
A node, when advertising the L2 flood reflector adjacency MUST
include the Flood Reflector Adjacency Sub-TLV in Extended IS
reachability TLV and MT-ISN TLV.
7. Adjacency Forming Procedures
To ensure loop-free routing the ingress routers MUST follow normal L2
computation to generate L2 routes. This is because nodes outside the
L1 area may not be aware that flooding reflection is performed. The
resulting short cuts through the L1 area needs to be able to easily
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calculate the egress L1/L2 router where the tunnel tail-end is
located.
To prevent complex scenarios of flood reflectors building L2
adjacencies within a cluster or across clusters or hierarchies of
reflectors, a flood reflector MUST never form an L2 adjacency with a
peer if the peer is not a client in the same Cluster ID. This
ensures a L2 computation on an ingress link or adjacency following a
flood reflector adjacency will always traverse a client of the flood
reflector to exit the flooding domain. This allows shortcuts through
the L1 area to be used without any danger of forwarding loops.
The Flood Reflector Cluster ID and flood reflector roles advertised
in the Flood Reflector TLVs in IIHs on a given interface are used to
ensure that flood reflector adjacencies that are established meet the
above criteria.
Depending on pseudo-node choice in case of a broadcast domain with
multiple flood reflectors attached this can lead to a partitioned LAN
and hence a router discovering such a condition MUST initiate an
alarm and declare misconfiguration.
8. Special Considerations
In pathological cases setting the overload bit in L1 (but not in L2)
can partition L1 forwarding, while allowing L2 reachability through
flood reflector adjacencies to exist. In such a case a node cannot
replace a route through a flood reflector adjacency with a L1
shortcut and the client can use the L2 tunnel to the flood reflector
for forwarding while it MUST initiate an alarm and declare
misconfiguration.
A flood reflector with directly L2 attached prefixes should advertise
those in L1 as well since based on preference of L1 routes the
clients will not try to use the L2 flood reflector adjacency to route
the packet towards them. A very, very corner case is when the flood
reflector is reachable via L2 flood reflector adjacency (due to
underlying L1 partition) only in which case the client can use the L2
tunnel to the flood reflector for forwarding towards those prefixes
while it MUST initiate an alarm and declare misconfiguration.
Instead of modifying the computation procedures one could imagine a
flood reflector solution where the Flood Reflector would re-advertise
the L2 prefixes with a 'third-party' next-hop but that would have
less desirable convergence properties than the solution proposed and
force a fork-lift of all L2 routers to make sure they disregard such
prefixes unless in the same L1 domain as the Flood Reflector.
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9. IANA Considerations
This document requests allocation for the following IS-IS TLVs and
Sub-TLVs.
9.1. New IS-IS TLV Codepoint
This document requests the following IS-IS TLV:
Value Name IIH LSP SNP Purge
----- --------------------------------- --- --- --- -----
TBD1 Flood Reflection y n n n
9.2. Sub TLVs for TLV 242
This document request the following registration in the "sub-TLVs for
TLV 242" registry.
Type Description
---- -----------
TBD2 Flood Reflection Discovery
9.3. Sub TLVs for TLV 22, 23, 25, 141, 222, and 223
This document requests the following registration in the "sub-TLVs
for TLV 22, 23, 25, 141, 222, and 223" registry.
Type Description 22 23 25 141 222 223
---- -------------------------------- --- --- --- --- --- ---
TBD3 Flood Reflector Adjacency y y y(s) y y y
10. Security Considerations
This document introduces no new security concerns to ISIS or other
specifications referenced in this document.
11. Acknowledgements
Thanks to Shraddha Hegde and others for thorough review.
12. References
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12.1. Informative References
[ID.draft-ietf-idr-bgp-optimal-route-reflection-19]
Raszuk et al., R., "BGP Optimal Route Reflection", July
2019.
[RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
Border Gateway Protocol 4 (BGP-4)", RFC 4271,
DOI 10.17487/RFC4271, January 2006,
<https://www.rfc-editor.org/info/rfc4271>.
[RFC4456] Bates, T., Chen, E., and R. Chandra, "BGP Route
Reflection: An Alternative to Full Mesh Internal BGP
(IBGP)", RFC 4456, DOI 10.17487/RFC4456, April 2006,
<https://www.rfc-editor.org/info/rfc4456>.
[RFC8099] Chen, H., Li, R., Retana, A., Yang, Y., and Z. Liu, "OSPF
Topology-Transparent Zone", RFC 8099,
DOI 10.17487/RFC8099, February 2017,
<https://www.rfc-editor.org/info/rfc8099>.
12.2. 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>.
[RFC7981] Ginsberg, L., Previdi, S., and M. Chen, "IS-IS Extensions
for Advertising Router Information", RFC 7981,
DOI 10.17487/RFC7981, October 2016,
<https://www.rfc-editor.org/info/rfc7981>.
Authors' Addresses
Tony Przygienda
Juniper
1137 Innovation Way
Sunnyvale, CA
USA
Email: prz@juniper.net
Przygienda, et al. Expires May 5, 2020 [Page 13]
Internet-Draft draft-przygienda-lsr-flood-reflection November 2019
Chris Bowers
Juniper
1137 Innovation Way
Sunnyvale, CA
USA
Email: cbowers@juniper.net
Yiu Lee
Comcast
1800 Bishops Gate Blvd
Mount Laurel, NJ 08054
US
Email: Yiu_Lee@comcast.com
Alankar Sharma
Comcast
1800 Bishops Gate Blvd
Mount Laurel, NJ 08054
US
Email: Alankar_Sharma@comcast.com
Russ White
Juniper
1137 Innovation Way
Sunnyvale, CA
USA
Email: russw@juniper.net
Przygienda, et al. Expires May 5, 2020 [Page 14]