IS-IS Flooding Scale Considerations
draft-ginsberg-lsr-isis-flooding-scale-02
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Networking Working Group L. Ginsberg
Internet-Draft P. Psenak
Intended status: Informational A. Lindem
Expires: October 19, 2020 Cisco Systems
T. Przygienda
Juniper
April 17, 2020
IS-IS Flooding Scale Considerations
draft-ginsberg-lsr-isis-flooding-scale-02
Abstract
Link State PDU flooding rates in use are much slower than what modern
networks can support. The use of IS-IS at larger scale requires
faster flooding rates to achieve desired convergence goals. This
document discusses issues associated with increasing flooding rates
and some recommended practices which allow faster flooding rates to
be used safely.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "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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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 October 19, 2020.
Ginsberg, et al. Expires October 19, 2020 [Page 1]
Internet-Draft draft-ginsberg-lsr-isis-flooding-scale April 2020
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Historical Behavior . . . . . . . . . . . . . . . . . . . . . 3
3. Flooding Rate and Convergence . . . . . . . . . . . . . . . . 4
3.1. Flow Control . . . . . . . . . . . . . . . . . . . . . . 5
3.2. Rate of LSP Acknowledgments . . . . . . . . . . . . . . . 7
3.3. Bandwidth Utilization . . . . . . . . . . . . . . . . . . 7
3.4. Packet Prioritization on Receive . . . . . . . . . . . . 7
4. Minimizing LSP Generation . . . . . . . . . . . . . . . . . . 8
5. Redundant Flooding . . . . . . . . . . . . . . . . . . . . . 10
6. Use of Jumbo Frames . . . . . . . . . . . . . . . . . . . . . 10
7. Deployment Considerations . . . . . . . . . . . . . . . . . . 10
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
9. Security Considerations . . . . . . . . . . . . . . . . . . . 11
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
11.1. Normative References . . . . . . . . . . . . . . . . . . 11
11.2. Informative References . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
1. Introduction
Link state IGPs such as Intermediate-System-to-Intermediate-System
(IS-IS) depend upon having consistent Link State Databases (LSDB) on
all Intermediate Systems (ISs) in the network in order to provide
correct forwarding of data packets. When topology changes occur,
new/updated Link State PDUs (LSPs) are propagated network-wide. The
speed of propagation is a key contributor to convergence time.
Historically, flooding rates have been conservative - on the order of
10s of LSPs/second. This derives from guidance in the base
specification [ISO10589] and early deployments when both CPU speeds
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