Internet DRAFT - draft-li-lsr-isis-link-ber
draft-li-lsr-isis-link-ber
Network Working Group C. Li
Internet-Draft G. Xu
Intended status: Informational Z. Hu
Expires: April 22, 2022 Z. Zhou
Huawei
October 19, 2021
IS-IS Extensions for Link Bit Error Ratio
draft-li-lsr-isis-link-ber-00
Abstract
In certain networks, 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 (TE)
Metric Extensions (RFC 8570). This draft provides the necessary IS-
IS extensions about the link bit error ratio (LBER) that need to be
used to describe network-performance.
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 BCP 14 [RFC2119]
[RFC8174] when, and only when, they appear in all capitals, as shown
here.
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
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Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 22, 2022.
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Copyright Notice
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document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. LBER Extensions to IS-IS . . . . . . . . . . . . . . . . . . 3
3. Sub-TLV Details . . . . . . . . . . . . . . . . . . . . . . . 3
3.1. Unidirectional Link BIT ERROR RATIO Sub-TLV . . . . . . . 3
4. Announcement Thresholds and Filters . . . . . . . . . . . . . 4
5. Announcement Suppression . . . . . . . . . . . . . . . . . . 4
6. Network Stability and Announcement Periodicity . . . . . . . 4
7. Enabling and Disabling Sub-TLVs . . . . . . . . . . . . . . . 4
8. Compatibility . . . . . . . . . . . . . . . . . . . . . . . . 4
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
11. Security Considerations . . . . . . . . . . . . . . . . . . . 5
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
In certain networks, 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 (TE)
Metric Extensions (RFC 8570). This draft provides the necessary IS-
IS extensions about the link bit errror ratio (LBER) that need to be
used to describe network-performance.A new sub-TLV is introduced for
IS-IS.
As other IS-IS TE Metric Extensions (e.g., unidirectional link loss,
unidirectional link delay), Unidirectional link bit error ratio
described in this dicument is also meant to be used as part of the
operation of the routing protocol to enhance Constrained Shortest
Path First (CSPF), or for other uses such as supplementing the data
used by the controller to compute the policy path.
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2. LBER Extensions to IS-IS
This document registers a new IS-IS TE sub-TLV in the "Sub-TLVs for
TLVs 22, 23, 141, 222, and 223" registry. This new sub-TLV provides
ways to distribute LBER.
This document registers a sub-TLV:
Type Description
----------------------------------------------------
TBD Unidirectional Link BIT ERROR RATIO
Figure 1
The new sub-TLV 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.
3. Sub-TLV Details
3.1. Unidirectional Link BIT ERROR RATIO Sub-TLV
This sub-TLV advertises the bit error ratio between two directly
connected IS-IS neighbors. The link bit error ratio advertised by
this sub-TLV MUST be the packet bit error from the local neighbor to
the remote neighbor (i.e., the forward-path loss). The format of
this sub-TLV is shown in the following diagram:
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 Bit Error Ratio |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+-+-+-+--+
Figure 2: Unidirectional Link BIT ERROR RATIO Sub-TLV for the IS-IS
extension
Type: TBD (suggested value 40) is to be assigned by IANA.
Length: 4.
A bit: This field 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 cleared,
the sub-TLV represents steady-state link performance.
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RESERVED: This field is reserved for future use. It MUST be set to 0
when sent and MUST be ignored when received.
Link Bit Error Ratio: This 24-bit field carries Link Bit Error Ratio
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 link bit error percentage that
can be expressed (the assumptions being that (1) precision is more
important on high-speed links than the ability to advertise link bit
error ratio greater than this and (2) high-speed links with over 50%
bit error are unusable). Therefore, measured values that are larger
than the field maximum SHOULD be encoded as the maximum value.
This sub-TLV is optional.
4. Announcement Thresholds and Filters
This document uses the same principle for announcement thresholds and
filters as described in RFC 8570.
5. Announcement Suppression
This document uses the same principle for announcement suppression as
described in RFC 8570.
6. Network Stability and Announcement Periodicity
This document uses the same principle for network stability and
announcement periodicity as described in RFC 8570.
7. Enabling and Disabling Sub-TLVs
Implementations MUST make it possible to enable or disable each sub-
TLV based on configuration.
8. Compatibility
Unrecognized sub-TLVs should be silently ignored.
9. Acknowledgements
TBD.
10. IANA Considerations
This document requests that IANA allocates new sub-TLV types as
defined in Section 2 from the "Sub-TLVs for TLVs 22, 23, 25, 141,
222, and 223 (Extended IS reachability, IS Neighbor Attribute, L2
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Bundle Member Attributes, inter-AS reachability information, MT-ISN,
and MT IS Neighbor Attribute TLVs)" registry as specified.
Value Description Reference
---------------------------------------------------------------
TBD Unidirectional LBER This document
Figure 3: Unidirectional LBER
11. Security Considerations
These extensions to IS-IS do not add any new security issues to the
existing IGP.
12. References
[RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic
Engineering", RFC 5305, DOI 10.17487/RFC5305, October
2008, <https://www.rfc-editor.org/info/rfc5305>.
[RFC8570] Ginsberg, L., Ed., Previdi, S., Ed., Giacalone, S., Ward,
D., Drake, J., and Q. Wu, "IS-IS Traffic Engineering (TE)
Metric Extensions", RFC 8570, DOI 10.17487/RFC8570, March
2019, <https://www.rfc-editor.org/info/rfc8570>.
Authors' Addresses
Chenxi Li
Huawei
Huawei Bld., No.156 Beiqing Rd.
Beijing 100095
China
Email: lichenxi1@huawei.com
Guoqi Xu
Huawei
Huawei Bld., No. 156 Beiqing Rd.
Beijing 100095
China
Email: xuguoqi@huawei.com
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Zhibo Hu
Huawei
Huawei Bld., No.156 Beiqing Rd.
Beijing 100095
China
Email: huzhibo@huawei.com
Tianran Zhou
Huawei
Huawei Bld., No. 156 Beiqing Rd.
Beijing 100095
China
Email: zhoutianran@huawei.com
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