Internet DRAFT - draft-ietf-isis-te-metric-extensions
draft-ietf-isis-te-metric-extensions
Networking Working Group S. Previdi, Ed.
Internet-Draft Cisco Systems, Inc.
Intended status: Standards Track S. Giacalone
Expires: August 15, 2016 Unaffiliated
D. Ward
Cisco Systems, Inc.
J. Drake
Juniper Networks
Q. Wu
Huawei
February 12, 2016
IS-IS Traffic Engineering (TE) Metric Extensions
draft-ietf-isis-te-metric-extensions-11
Abstract
In certain networks, such as, but not limited to, financial
information networks (e.g. stock market data providers), network
performance criteria (e.g. latency) are becoming as critical to data
path selection as other metrics.
This document describes extensions to IS-IS Traffic Engineering
Extensions (RFC5305) such that network performance information can be
distributed and collected in a scalable fashion. The information
distributed using IS-IS TE Metric Extensions can then be used to make
path selection decisions based on network performance.
Note that this document only covers the mechanisms with which network
performance information is distributed. The mechanisms for measuring
network performance or acting on that information, once distributed,
are outside the scope of this document.
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].
In this document, these words will appear with that interpretation
only when in ALL CAPS. Lower case uses of these words are not to be
interpreted as carrying RFC-2119 significance.
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Status of This Memo
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This Internet-Draft will expire on August 15, 2016.
Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. TE Metric Extensions to IS-IS . . . . . . . . . . . . . . . . 4
3. Interface and Neighbor Addresses . . . . . . . . . . . . . . 5
4. Sub TLV Details . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. Unidirectional Link Delay Sub-TLV . . . . . . . . . . . . 6
4.2. Min/Max Unidirectional Link Delay Sub-TLV . . . . . . . . 7
4.3. Unidirectional Delay Variation Sub-TLV . . . . . . . . . 8
4.4. Unidirectional Link Loss Sub-TLV . . . . . . . . . . . . 8
4.5. Unidirectional Residual Bandwidth Sub-TLV . . . . . . . . 9
4.6. Unidirectional Available Bandwidth Sub-TLV . . . . . . . 10
4.7. Unidirectional Utilized Bandwidth Sub-TLV . . . . . . . . 11
5. Announcement Thresholds and Filters . . . . . . . . . . . . . 12
6. Announcement Suppression . . . . . . . . . . . . . . . . . . 13
7. Network Stability and Announcement Periodicity . . . . . . . 13
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8. Enabling and Disabling Sub-TLVs . . . . . . . . . . . . . . . 14
9. Static Metric Override . . . . . . . . . . . . . . . . . . . 14
10. Compatibility . . . . . . . . . . . . . . . . . . . . . . . . 14
11. Security Considerations . . . . . . . . . . . . . . . . . . . 14
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
13. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 15
14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 16
15. References . . . . . . . . . . . . . . . . . . . . . . . . . 16
15.1. Normative References . . . . . . . . . . . . . . . . . . 16
15.2. Informative References . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17
1. Introduction
In certain networks, such as, but not limited to, financial
information networks (e.g. stock market data providers), network
performance information (e.g. latency) is becoming as critical to
data path selection as other metrics.
In these networks, extremely large amounts of money rest on the
ability to access market data in "real time" and to predictably make
trades faster than the competition. Because of this, using metrics
such as hop count or cost as routing metrics is becoming only
tangentially important. Rather, it would be beneficial to be able to
make path selection decisions based on performance data (such as
latency) in a cost-effective and scalable way.
This document describes extensions (hereafter called "IS-IS TE Metric
Extensions") to IS-IS Extended Reachability TLV defined in [RFC5305],
that can be used to distribute network performance information (such
as link delay, delay variation, packet loss, residual bandwidth, and
available bandwidth).
The data distributed by the IS-IS TE Metric Extensions proposed in
this document is meant to be used as part of the operation of the
routing protocol (e.g. by replacing cost with latency or considering
bandwidth as well as cost), by enhancing Constrained-SPF (CSPF), or
for other uses such as supplementing the data used by an ALTO server
[RFC7285]. With respect to CSPF, the data distributed by IS-IS TE
Metric Extensions can be used to setup, fail over, and fail back data
paths using protocols such as RSVP-TE [RFC3209].
Note that the mechanisms described in this document only disseminate
performance information. The methods for initially gathering that
performance information, such as [RFC6375], or acting on it once it
is distributed are outside the scope of this document. Example
mechanisms to measure latency, delay variation, and loss in an MPLS
network are given in [RFC6374]. While this document does not specify
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how the performance information should be obtained, the measurement
of delay SHOULD NOT vary significantly based upon the offered traffic
load. Thus, queuing delays SHOULD NOT be included in the delay
measurement. For links such as Forwarding Adjacencies, care must be
taken that measurement of the associated delay avoids significant
queuing delay; that could be accomplished in a variety of ways,
including either by measuring with a traffic class that experiences
minimal queuing or by summing the measured link delays of the
components of the link's path.
2. TE Metric Extensions to IS-IS
This document proposes new IS-IS TE sub-TLVs that can be announced in
TLVs 22, 141, 222, and 223 in order to distribute network performance
information. The extensions in this document build on the ones
provided in IS-IS TE [RFC5305] and GMPLS [RFC4203].
IS-IS Extended Reachability TLV 22 (defined in [RFC5305]), Inter-AS
reachability information TLV 141 (defined in [RFC5316]) and MT-ISIS
TLV 222 (defined in [RFC5120]) have nested sub-TLVs which permit the
TLVs to be readily extended. This document proposes several
additional sub-TLVs:
Type Value
----------------------------------------------------
33 (Suggested) Unidirectional Link Delay
34 (Suggested) Min/Max Unidirectional Link Delay
35 (Suggested) Unidirectional Delay Variation
36 (Suggested) Unidirectional Packet Loss
37 (Suggested) Unidirectional Residual Bandwidth
38 (Suggested) Unidirectional Available Bandwidth
39 (Suggested) Unidirectional Bandwidth Utilization
As can be seen in the list above, the sub-TLVs described in this
document carry different types of network performance information.
The new sub-TLVs include a bit called the Anomalous (or "A") bit.
When the A bit is clear (or when the sub-TLV does not include an A
bit), the sub-TLV describes steady state link performance. This
information could conceivably be used to construct a steady state
performance topology for initial tunnel path computation, or to
verify alternative failover paths.
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When network performance violates configurable link-local thresholds
a sub-TLV with the A bit set is advertised. These sub-TLVs could be
used by the receiving node to determine whether to fail traffic to a
backup path, or whether to calculate an entirely new path. From an
MPLS perspective, the intent of the A bit is to permit LSP ingress
nodes to:
A) Determine whether the link referenced in the sub-TLV affects any
of the LSPs for which it is ingress. If there are, then:
B) Determine whether those LSPs still meet end-to-end performance
objectives. If not, then:
C) The node could then conceivably move affected traffic to a pre-
established protection LSP or establish a new LSP and place the
traffic in it.
If link performance then improves beyond a configurable minimum value
(reuse threshold), that sub-TLV can be re-advertised with the
Anomalous bit cleared. In this case, a receiving node can
conceivably do whatever re-optimization (or failback) it wishes to do
(including nothing).
Note that when a sub-TLV does not include the A bit, that sub-TLV
cannot be used for failover purposes. The A bit was intentionally
omitted from some sub-TLVs to help mitigate oscillations. See
Section 5 for more information.
Consistent with existing IS-IS TE specification [RFC5305], the
bandwidth advertisements defined in this draft MUST be encoded as
IEEE floating point values. The delay and delay variation
advertisements defined in this draft MUST be encoded as integer
values. Delay values MUST be quantified in units of microseconds,
packet loss MUST be quantified as a percentage of packets sent, and
bandwidth MUST be sent as bytes per second. All values (except
residual bandwidth) MUST be calculated as rolling averages where the
averaging period MUST be a configurable period of time. See
Section 5 for more information.
3. Interface and Neighbor Addresses
The use of IS-IS TE Metric Extensions sub-TLVs is not confined to the
TE context. In other words, IS-IS TE Metric Extensions sub-TLVs
defined in this document can also be used for computing paths in the
absence of a TE subsystem.
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However, as for the TE case, Interface Address and Neighbor Address
sub-TLVs (IPv4 or IPv6) MUST be present. The encoding is defined in
[RFC5305] for IPv4 and in [RFC6119] for IPv6.
4. Sub TLV Details
4.1. Unidirectional Link Delay Sub-TLV
This sub-TLV advertises the average link delay between two directly
connected IS-IS neighbors. The delay advertised by this sub-TLV MUST
be the delay from the local neighbor to the remote one (i.e. the
forward path latency). The format of this sub-TLV is shown in the
following diagram:
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A| RESERVED | Delay |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
Figure 1
Type: TBA (suggested value: 33).
Length: 4.
A-bit. The A-bit represents the Anomalous (A) bit. The A-bit is set
when the measured value of this parameter exceeds its configured
maximum threshold. The A bit is cleared when the measured value
falls below its configured reuse threshold. If the A-bit is clear,
the sub-TLV represents steady state link performance.
RESERVED. This field is reserved for future use. It MUST be set to
0 when sent and MUST be ignored when received.
Delay. This 24-bit field carries the average link delay over a
configurable interval in micro-seconds, encoded as an integer value.
When set to the maximum value 16,777,215 (16.777215 sec), then the
delay is at least that value and may be larger.
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4.2. Min/Max Unidirectional Link Delay Sub-TLV
This sub-TLV advertises the minimum and maximum delay values between
two directly connected IS-IS neighbors. The delay advertised by this
sub-TLV MUST be the delay from the local neighbor to the remote one
(i.e. the forward path latency). The format of this sub-TLV is shown
in the following diagram:
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A| RESERVED | Min Delay |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RESERVED | Max Delay |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
Figure 2
Type: TBA (suggested value: 34).
Length: 8.
This field represents the Anomalous (A) bit. The A bit is set when
one or more measured values exceed a configured maximum threshold.
The A bit is cleared when the measured value falls below its
configured reuse threshold. If the A bit is clear, the sub-TLV
represents steady state link performance.
RESERVED. This field is reserved for future use. It MUST be set to
0 when sent and MUST be ignored when received.
Min Delay. This 24-bit field carries minimum measured link delay
value (in microseconds) over a configurable interval, encoded as an
integer value.
Max Delay. This 24-bit field carries the maximum measured link delay
value (in microseconds) over a configurable interval, encoded as an
integer value.
Implementations MAY also permit the configuration of an offset value
(in microseconds) to be added to the measured delay value, to
facilitate the communication of operator specific delay constraints.
It is possible for the Min and Max delay to be the same value.
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When the delay value (Min or Max) is set to maximum value 16,777,215
(16.777215 sec), then the delay is at least that value and may be
larger.
4.3. Unidirectional Delay Variation Sub-TLV
This sub-TLV advertises the average link delay variation between two
directly connected IS-IS neighbors. The delay variation advertised
by this sub-TLV MUST be the delay from the local neighbor to the
remote one (i.e. the forward path latency). The format of this sub-
TLV is shown in the following diagram:
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RESERVED | Delay Variation |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
Figure 3
Type: TBA (suggested value: 35).
Length: 4.
RESERVED. This field is reserved for future use. It MUST be set to
0 when sent and MUST be ignored when received.
Delay Variation. This 24-bit field carries the average link delay
variation over a configurable interval in microseconds, encoded as an
integer value. When set to 0, it has not been measured. When set to
the maximum value 16,777,215 (16.777215 sec), then the delay is at
least that value and may be larger.
4.4. Unidirectional Link Loss Sub-TLV
This sub-TLV advertises the loss (as a packet percentage) between two
directly connected IS-IS neighbors. The link loss advertised by this
sub-TLV MUST be the packet loss from the local neighbor to the remote
one (i.e. the forward path loss). The format of this sub-TLV is
shown in the following diagram:
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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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|A| RESERVED | Link Loss |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
This sub-TLV has a type of TBD3.
The length is 4.
where:
Type: TBA (suggested value: 36).
Length: 4.
A-bit. The A-bit represents the Anomalous (A) bit. The A-bit is set
when the measured value of this parameter exceeds its configured
maximum threshold. The A bit is cleared when the measured value
falls below its configured reuse threshold. If the A-bit is clear,
the sub-TLV represents steady state link performance.
RESERVED. This field is reserved for future use. It MUST be set to
0 when sent and MUST be ignored when received.
Link Loss. This 24-bit field carries link packet loss as a
percentage of the total traffic sent over a configurable interval.
The basic unit is 0.000003%, where (2^24 - 2) is 50.331642%. This
value is the highest packet loss percentage that can be expressed
(the assumption being that precision is more important on high speed
links than the ability to advertise loss rates greater than this, and
that high speed links with over 50% loss are unusable). Therefore,
measured values that are larger than the field maximum SHOULD be
encoded as the maximum value.
4.5. Unidirectional Residual Bandwidth Sub-TLV
This sub-TLV advertises the residual bandwidth between two directly
connected IS-IS neighbors. The residual bandwidth advertised by this
sub-TLV MUST be the residual bandwidth from the system originating
the LSA to its neighbor.
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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 | RESERVED |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Residual Bandwidth |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
Type: TBA (suggested value: 37).
Length: 4.
RESERVED. This field is reserved for future use. It MUST be set to
0 when sent and MUST be ignored when received.
Residual Bandwidth. This field carries the residual bandwidth on a
link, forwarding adjacency [RFC4206], or bundled link in IEEE
floating point format with units of bytes per second. For a link or
forwarding adjacency, residual bandwidth is defined to be Maximum
Bandwidth [RFC5305] minus the bandwidth currently allocated to RSVP-
TE LSPs. For a bundled link, residual bandwidth is defined to be the
sum of the component link residual bandwidths.
The calculation of Residual Bandwidth is different than that of
Unreserved Bandwidth [RFC5305]. Residual Bandwidth subtracts tunnel
reservations from Maximum Bandwidth (i.e. the link capacity)
[RFC5305] and provides an aggregated remainder across priorities.
Unreserved Bandwidth, on the other hand, is subtracted from the
Maximum Reservable Bandwidth (the bandwidth that can theoretically be
reserved) and provides per priority remainders. Residual Bandwidth
and Unreserved Bandwidth [RFC5305] can be used concurrently, and each
has a separate use case (e.g. the former can be used for applications
like Weighted ECMP while the latter can be used for call admission
control).
4.6. Unidirectional Available Bandwidth Sub-TLV
This sub-TLV advertises the available bandwidth between two directly
connected IS-IS neighbors. The available bandwidth advertised by
this sub-TLV MUST be the available bandwidth from the system
originating this sub-TLV. The format of this sub-TLV is shown in the
following diagram:
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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 | RESERVED |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Available Bandwidth |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
Figure 4
Type: TBA (suggested value: 38).
Length: 4.
RESERVED. This field is reserved for future use. It MUST be set to
0 when sent and MUST be ignored when received.
Available Bandwidth. This field carries the available bandwidth on a
link, forwarding adjacency, or bundled link in IEEE floating point
format with units of bytes per second. For a link or forwarding
adjacency, available bandwidth is defined to be residual bandwidth
(see Section 4.5 minus the measured bandwidth used for the actual
forwarding of non-RSVP-TE LSP packets. For a bundled link, available
bandwidth is defined to be the sum of the component link available
bandwidths minus the measured bandwidth used for the actual
forwarding of non-RSVP-TE Label Switched Paths packets. For a
bundled link, available bandwidth is defined to be the sum of the
component link available bandwidths.
4.7. Unidirectional Utilized Bandwidth Sub-TLV
This sub-TLV advertises the bandwidth utilization between two
directly connected IS-IS neighbors. The bandwidth utilization
advertised by this sub-TLV MUST be the bandwidth from the system
originating this sub-TLV. The format of this sub-TLV is shown in the
following diagram:
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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 | RESERVED |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Utilized Bandwidth |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
Figure 5
Type: TBA (suggested value: 39).
Length: 4.
RESERVED. This field is reserved for future use. It MUST be set to
0 when sent and MUST be ignored when received.
This field carries the bandwidth utilization on a link, forwarding
adjacency, or bundled link in IEEE floating-point format with units
of bytes per second. For a link or forwarding adjacency, bandwidth
utilization represents the actual utilization of the link (i.e., as
measured by the advertising node). For a bundled link, bandwidth
utilization is defined to be the sum of the component link bandwidth
utilizations.
5. Announcement Thresholds and Filters
The values advertised in all sub-TLVs (except Min/Max delay and
residual bandwidth) MUST represent an average over a period or be
obtained by a filter that is reasonably representative of an average.
For example, a rolling average is one such filter.
Min and max delay MUST each be derived in one of the following ways:
by taking the lowest and/or highest measured value over a measurement
interval, or by making use of a filter or other technique to obtain a
reasonable representation of a min and max value representative of
the interval, with compensation for outliers.
The measurement interval, any filter coefficients, and any
advertisement intervals MUST be configurable per sub-TLV.
In addition to the measurement intervals governing re-advertisement,
implementations SHOULD provide per sub-TLV configurable accelerated
advertisement thresholds, such that:
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1. If the measured parameter falls outside a configured upper
bound for all but the min delay metric (or lower bound for
min delay metric only) and the advertised sub-TLV is not
already outside that bound or,
2. If the difference between the last advertised value and
current measured value exceed a configured threshold then,
3. The advertisement is made immediately.
4. For sub-TLVs which include an A-bit, an additional
threshold SHOULD be included corresponding to the
threshold for which the performance is considered
anomalous (and sub-TLVs with the A-bit are sent). The
A-bit is cleared when the sub-TLV's performance has
been below (or re-crosses) this threshold for an
advertisement interval(s) to permit fail back.
To prevent oscillations, only the high threshold or the low threshold
(but not both) may be used to trigger any given sub-TLV that supports
both.
Additionally, once outside of the bounds of the threshold, any
readvertisement of a measurement within the bounds would remain
governed solely by the measurement interval for that sub-TLV.
6. Announcement Suppression
When link performance values change by small amounts that fall under
thresholds that would cause the announcement of a sub-TLV,
implementations SHOULD suppress sub-TLV readvertisement and/or
lengthen the period within which they are refreshed.
Only the accelerated advertisement threshold mechanism described in
Section 5 may shorten the re-advertisement interval. All suppression
and re-advertisement interval backoff timer features SHOULD be
configurable.
7. Network Stability and Announcement Periodicity
Section 5 and Section 6 provide configurable mechanisms to bound the
number of re-advertisements. Instability might occur in very large
networks if measurement intervals are set low enough to overwhelm the
processing of flooded information at some of the routers in the
topology. Therefore care should be taken in setting these values.
Additionally, the default measurement interval for all sub-TLVs
SHOULD be 30 seconds.
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Announcements MUST also be able to be throttled using configurable
inter-update throttle timers. The minimum announcement periodicity
is 1 announcement per second. The default value SHOULD be set to 120
seconds.
Implementations SHOULD NOT permit the inter-update timer to be lower
than the measurement interval.
Furthermore, it is RECOMMENDED that any underlying performance
measurement mechanisms not include any significant buffer delay, any
significant buffer induced delay variation, or any significant loss
due to buffer overflow or due to active queue management.
8. Enabling and Disabling Sub-TLVs
Implementations MUST make it possible to individually enable or
disable each sub-TLV based on configuration.
9. Static Metric Override
Implementations SHOULD permit the static configuration and/or manual
override of dynamic measurements for each sub-TLV in order to
simplify migration and to mitigate scenarios where dynamic
measurements are not possible.
10. Compatibility
As per [RFC5305], unrecognized sub-TLVs should be silently ignored.
11. Security Considerations
The subTLVs introduced in this document allow an operator to
advertise state information of links (bandwidth, delay) that could be
sensitive and that an operator may not want to disclose.
Section 7 describe a mechanism in order to ensure network stability
when the new sub-TLVs defined in this document are advertised.
Implementation SHOULD follow the described guidelines in order to
mitigate the instability risk.
[RFC5304] describes an authentication method for IS-IS LSP that
allows cryptographic authentication of IS-IS LSPs.
It is anticipated that in most deployments, IS-IS protocol is used
within an infrastructure entirely under control of the same operator.
However, it is worth to consider that the effect of sending IS-IS
Traffic Engineering sub-TLVs over insecure links could result in a
man-in-the-middle attacker delaying real time data to a given site
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(or destination), which could negatively affect the value of the data
for that site/destination. The use of LSP cryptographic
authentication allows to mitigate the risk of man-in-the-middle
attack.
12. IANA Considerations
IANA maintains the registry for the sub-TLVs. IS-IS TE Metric
Extensions will require one new type code per sub-TLV defined in this
document in the following sub-TLV registry: TLVs 22, 23, 141, 222,
and 223:
Type Value
----------------------------------------------------
33 (Suggested) Unidirectional Link Delay
34 (Suggested) Min/Max Unidirectional Link Delay
35 (Suggested) Unidirectional Delay Variation
36 (Suggested) Unidirectional Packet Loss
37 (Suggested) Unidirectional Residual Bandwidth
38 (Suggested) Unidirectional Available Bandwidth
39 (Suggested) Unidirectional Bandwidth Utilization
13. Contributors
The following people gave a substantial contribution to the content
of this document and should be considered as co-authors:
Alia Atlas
Juniper Networks
US
akatlas@juniper.net
Clarence Filsfils
Cisco Systems Inc.
Belgium
Email: cfilsfil@cisco.com
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14. Acknowledgements
The authors would like to recognize Ayman Soliman, Nabil Bitar, David
McDysan, Les Ginsberg, Edward Crabbe, Don Fedyk, Hannes Gredler, Uma
Chunduri, Alvaro Retana, Brian Weis and Barry Leiba for their
contribution and review of this document.
The authors also recognize Curtis Villamizar for significant comments
and direct content collaboration.
15. References
15.1. 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,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC4206] Kompella, K. and Y. Rekhter, "Label Switched Paths (LSP)
Hierarchy with Generalized Multi-Protocol Label Switching
(GMPLS) Traffic Engineering (TE)", RFC 4206,
DOI 10.17487/RFC4206, October 2005,
<http://www.rfc-editor.org/info/rfc4206>.
[RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi
Topology (MT) Routing in Intermediate System to
Intermediate Systems (IS-ISs)", RFC 5120,
DOI 10.17487/RFC5120, February 2008,
<http://www.rfc-editor.org/info/rfc5120>.
[RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic
Authentication", RFC 5304, DOI 10.17487/RFC5304, October
2008, <http://www.rfc-editor.org/info/rfc5304>.
[RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic
Engineering", RFC 5305, DOI 10.17487/RFC5305, October
2008, <http://www.rfc-editor.org/info/rfc5305>.
[RFC5316] Chen, M., Zhang, R., and X. Duan, "ISIS Extensions in
Support of Inter-Autonomous System (AS) MPLS and GMPLS
Traffic Engineering", RFC 5316, DOI 10.17487/RFC5316,
December 2008, <http://www.rfc-editor.org/info/rfc5316>.
[RFC6119] Harrison, J., Berger, J., and M. Bartlett, "IPv6 Traffic
Engineering in IS-IS", RFC 6119, DOI 10.17487/RFC6119,
February 2011, <http://www.rfc-editor.org/info/rfc6119>.
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15.2. Informative References
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001,
<http://www.rfc-editor.org/info/rfc3209>.
[RFC4203] Kompella, K., Ed. and Y. Rekhter, Ed., "OSPF Extensions in
Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 4203, DOI 10.17487/RFC4203, October 2005,
<http://www.rfc-editor.org/info/rfc4203>.
[RFC6374] Frost, D. and S. Bryant, "Packet Loss and Delay
Measurement for MPLS Networks", RFC 6374,
DOI 10.17487/RFC6374, September 2011,
<http://www.rfc-editor.org/info/rfc6374>.
[RFC6375] Frost, D., Ed. and S. Bryant, Ed., "A Packet Loss and
Delay Measurement Profile for MPLS-Based Transport
Networks", RFC 6375, DOI 10.17487/RFC6375, September 2011,
<http://www.rfc-editor.org/info/rfc6375>.
[RFC7285] Alimi, R., Ed., Penno, R., Ed., Yang, Y., Ed., Kiesel, S.,
Previdi, S., Roome, W., Shalunov, S., and R. Woundy,
"Application-Layer Traffic Optimization (ALTO) Protocol",
RFC 7285, DOI 10.17487/RFC7285, September 2014,
<http://www.rfc-editor.org/info/rfc7285>.
Authors' Addresses
Stefano Previdi (editor)
Cisco Systems, Inc.
Via Del Serafico 200
Rome 00191
IT
Email: sprevidi@cisco.com
Spencer Giacalone
Unaffiliated
Email: spencer.giacalone@gmail.com
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Dave Ward
Cisco Systems, Inc.
3700 Cisco Way
SAN JOSE, CA 95134
US
Email: wardd@cisco.com
John Drake
Juniper Networks
1194 N. Mathilda Ave.
Sunnyvale, CA 94089
USA
Email: jdrake@juniper.net
Qin Wu
Huawei
101 Software Avenue, Yuhua District
Nanjing, Jiangsu 210012
China
Email: sunseawq@huawei.com
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