Transparent Interconnection of Lots of Links (TRILL): ARP and Neighbor Discovery (ND) Optimization
RFC 8302
Internet Engineering Task Force (IETF) Y. Li
Request for Comments: 8302 D. Eastlake 3rd
Category: Standards Track L. Dunbar
ISSN: 2070-1721 Huawei Technologies
R. Perlman
Dell EMC
M. Umair
Cisco
January 2018
Transparent Interconnection of Lots of Links (TRILL):
ARP and Neighbor Discovery (ND) Optimization
Abstract
This document describes mechanisms to optimize the Address Resolution
Protocol (ARP) and Neighbor Discovery (ND) traffic in a Transparent
Interconnection of Lots of Links (TRILL) campus. TRILL switches
maintain a cache of IP / Media Access Control (MAC) address / Data
Label bindings that are learned from ARP/ND requests and responses
that pass through them. In many cases, this cache allows an edge
Routing Bridge (RBridge) to avoid flooding an ARP/ND request by
either responding to it directly or encapsulating it and unicasting
it. Such optimization reduces packet flooding over a TRILL campus.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8302.
Li, et al. Standards Track [Page 1]
RFC 8302 TRILL ARP/ND Optimization January 2018
Copyright Notice
Copyright (c) 2018 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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. ARP/ND Optimization Requirement and Solution . . . . . . . . 4
3. IP/MAC Address Mappings . . . . . . . . . . . . . . . . . . . 5
4. Handling ARP/ND/SEND Messages . . . . . . . . . . . . . . . . 6
4.1. SEND Considerations . . . . . . . . . . . . . . . . . . . 7
4.2. Address Verification . . . . . . . . . . . . . . . . . . 7
4.3. Extracting Local Mapping Information for End-Station
IP/MAC Addresses . . . . . . . . . . . . . . . . . . . . 8
4.4. Determining How to Reply to ARP/ND . . . . . . . . . . . 9
4.5. Determining How to Handle the ARP/ND Response . . . . . . 10
5. Handling of Reverse Address Resolution Protocol (RARP)
Messages . . . . . . . . . . . . . . . . . . . . . . . . . . 11
6. Handling of DHCP Messages . . . . . . . . . . . . . . . . . . 11
7. Handling of Duplicate IP Addresses . . . . . . . . . . . . . 11
8. RBridge ARP/ND Cache Liveness and MAC Mobility . . . . . . . 12
9. Security Considerations . . . . . . . . . . . . . . . . . . . 13
9.1. Data-Plane-Based Considerations . . . . . . . . . . . . . 13
9.2. Directory-Based Considerations . . . . . . . . . . . . . 14
9.3. Use of the Confidence Level Feature . . . . . . . . . . . 14
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
11.1. Normative References . . . . . . . . . . . . . . . . . . 15
11.2. Informative References . . . . . . . . . . . . . . . . . 16
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 17
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18
Li, et al. Standards Track [Page 2]
RFC 8302 TRILL ARP/ND Optimization January 2018
1. Introduction
ARP [RFC826] and ND [RFC4861] messages are normally sent by broadcast
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