Path Maximum Transmission Unit Discovery (PMTUD) for Bit Index Explicit Replication (BIER) Layer
draft-ietf-bier-path-mtu-discovery-06
BIER Working Group G. Mirsky
Internet-Draft ZTE Corp.
Intended status: Standards Track T. Przygienda
Expires: December 6, 2019 Juniper Networks
A. Dolganow
Individual contributor
June 4, 2019
Path Maximum Transmission Unit Discovery (PMTUD) for Bit Index Explicit
Replication (BIER) Layer
draft-ietf-bier-path-mtu-discovery-06
Abstract
This document describes Path Maximum Transmission Unit Discovery
(PMTUD) in Bit Indexed Explicit Replication (BIER) layer.
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 December 6, 2019.
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
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
Mirsky, et al. Expires December 6, 2019 [Page 1]
Internet-Draft PMTUD for BIER June 2019
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Conventions used in this document . . . . . . . . . . . . 3
1.1.1. Terminology . . . . . . . . . . . . . . . . . . . . . 3
1.1.2. Requirements Language . . . . . . . . . . . . . . . . 3
2. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 3
3. PMTUD Mechanism for BIER . . . . . . . . . . . . . . . . . . 4
3.1. Data TLV for BIER Ping . . . . . . . . . . . . . . . . . 6
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
5. Security Considerations . . . . . . . . . . . . . . . . . . . 7
6. Acknowledgment . . . . . . . . . . . . . . . . . . . . . . . 7
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.1. Normative References . . . . . . . . . . . . . . . . . . 7
7.2. Informative References . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
In packet switched networks, when a host seeks to transmit data to a
target destination, the data is transmitted as a set of packets. In
many cases, it is more efficient to use the largest size packets that
are less than or equal to the least Maximum Transmission Unit (MTU)
for any forwarding device along the routed path to the IP destination
for these packets. Such "least MTU" is known as Path MTU (PMTU).
Fragmentation or packet drop, silent or not, may occur on hops along
the route where an MTU is smaller than the size of the datagram. To
avoid any of the listed above behaviors, the packet source must find
the value of the least MTU, i.e. PMTU, that will be encountered along
the route that a set of packets will follow to reach the given set of
destinations. Such MTU determination along a specific path is
referred to as path MTU discovery (PMTUD).
[RFC8279] introduces and explains Bit Index Explicit Replication
(BIER) architecture and how it supports forwarding of multicast data
packets. A BIER domain consists of Bit-Forwarding Routers (BFRs)
that are uniquely identified by their respective BFR-ids. An ingress
border router (acting as a Bit Forwarding Ingress Router (BFIR))
inserts a Forwarding Bit Mask (F-BM) into a packet. Each targeted
egress node (referred to as a Bit Forwarding Egress Router (BFER)) is
represented by Bit Mask Position (BMP) in the BMS. A transit or
intermediate BIER node, referred to as BFR, forwards BIER
encapsulated packets to BFERs, identified by respective BMPs,
Show full document text