PIM Light
draft-hb-pim-light-00
The information below is for an old version of the document.
| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Authors | Hooman Bidgoli , Stig Venaas , Mankamana Prasad Mishra , Zhaohui (Jeffrey) Zhang , Mike McBride | ||
| Last updated | 2021-10-25 | ||
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| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
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| IESG | IESG state | I-D Exists | |
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draft-hb-pim-light-00
Network Working Group H. Bidgoli, Ed.
Internet-Draft Nokia
Intended status: Standards Track S. Venaas
Expires: 28 April 2022 Cisco System, Inc.
M. Mishra
Cisco System
Z. Zhang
Juniper Networks
M. McBride
Futurewei Technologies Inc.
25 October 2021
PIM Light
draft-hb-pim-light-00
Abstract
This document specifies a new Protocol Independent Multicast
interface which does not need PIM Hello to accept PIM Join/Prunes or
PIM Asserts.
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 28 April 2022.
Copyright Notice
Copyright (c) 2021 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
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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 the Trust Legal Provisions and are
provided without warranty as described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions used in this document . . . . . . . . . . . . . . 2
2.1. Definitions . . . . . . . . . . . . . . . . . . . . . . . 2
3. PIM Light Interface . . . . . . . . . . . . . . . . . . . . . 3
3.1. PLI Configuration . . . . . . . . . . . . . . . . . . . . 4
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
5. Security Considerations . . . . . . . . . . . . . . . . . . . 4
6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 4
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
7.1. Normative References . . . . . . . . . . . . . . . . . . 4
7.2. Informative References . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
It might be desirable to create a PIM interface between routers where
only PIM Join/Prunes and Asserts packets are triggered over it
without having a full PIM neighbor discovery. As an example, this
type of PIM interface can be useful in some scenarios where the
multicast state needs to be signaled over a network or medium which
is not capable of creating full PIM neighborship between its Peer
Routers. These type of PIM interfaces are called PIM Light
Interfaces (PLI).
2. Conventions used in this document
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.
2.1. Definitions
This draft uses definitions used in [RFC7761]
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3. PIM Light Interface
RFC [RFC7761] section 4.3.1 describes the PIM nighbor discovery via
Hello messages. It also describes that PIM Join/Prune or Assert
messages are not accepted from a router unless a Hello message has
been heard from that router.
In some scenarios it is desired to build a multicast state between
two directly attach or remote routers without establishing a PIM
neighborship. There could be many reasons for this desired, but one
example is the desired to signal multicast states upstream between
two PIM Domains via a network or medium that is not optimized for PIM
Neighbor establishment. A BIER network is an example of this, where
the BIER network is connecting two PIM domains as per
[draft-hfa-bier-pim-signaling] and the multicast states from the
hosts to the source are signaled via two edge PIM networks through
the BIER domain.
A PIM Light Interface (PLI) does accept Join/Prune and Assert
messages from a unknown PIM router, without receiving a PIM Hello
message form other routers. Lack of Hello Messages on a PLI means
there is no mechanism to learn about the neighboring PIM routers on
each interface and there is no DR Priority options communicated
between Routers either. As such the router doesn't create any
General-Purpose state for neighboring PIM routers and it accepts and
installs each Join message from upstream routers in its multicast
routing table.
Because of this a PLI needs to be created in very especial cases and
the application that is using these PLIs should ensure there is no
multicast duplication of packets. As an example, multiple upstream
routers sending the same multicast stream to a single downstream
router.
As an example, in a BIER domain which is connecting 2 PIM networks.
A PLI can be established between two edge BIER routers and only
multicast states communicated via PIM Join/prunes over the BIER
domain. In this case to ensure there is no multicast stream
duplication the PIM routers attached on each side of the BIER domain
might want to establish PIM Adjacency via [RFC7761] to ensure DR
selection on the edge of the BIER router and PLI is used in core of
the BIER Domain.
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3.1. PLI Configuration
Since a PLI doesn't support PIM Hello Messages to discover other PIM
routers, for security reasons, there needs to be a mechanism to
enable PLI on an interface or the router. This can be achieved via
different methods and is implementation specific. As an example:
* For Point to Point interface PLI can be enabled on an interface
that is accepting the PIM Join/Prune or Assert messages only.
* A PLI can also be configured on a logical interface or a tunnel
interface, like a MPLS tunnel or a GRE tunnel to accept PIM Join/
Prune or Assert messages.
* In some cases it is not possible to configure a PLI between two
routers, as an example in a BIER network where multicast states
are communicated via PIM Join/Prunes. As per
[draft-hfa-bier-pim-signaling] there can be multiple BIER Edge
routers that can signal their desire for a multicast state. In
these scenarios the router needs to be configured to support PLI
and only accept PIM Join/Prune or Assert messages based on this
global configuration
4. IANA Considerations
IANA is requested to assign a value (TBD) to the BIER Information
Vector PIM Join Attribute from the PIM Join Attribute Types registry.
5. Security Considerations
6. Acknowledgments
7. References
7.1. Normative References
[draft-hfa-bier-pim-signaling]
"H.Bidgoli, F.XU, J. Kotalwar, I. Wijnands, M.Mishra, Z.
Zhang, "PIM Signaling Through BIER Core"", July 2021.
[RFC2119] "S. Brandner, "Key words for use in RFCs to Indicate
Requirement Levels"", March 1997.
[RFC7761] "B.Fenner, M.Handley, H. Holbrook, I. Kouvelas, R. Parekh,
Z.Zhang "PIM Sparse Mode"", March 2016.
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[RFC8174] "B. Leiba, "ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words"", May 2017.
7.2. Informative References
[RFC8279] "Wijnands, IJ., Rosen, E., Dolganow, A., Przygienda, T.
and S. Aldrin, "Multicast using Bit Index Explicit
Replication"", October 2016.
Authors' Addresses
Hooman Bidgoli (editor)
Nokia
Ottawa
Canada
Email: hooman.bidgoli@nokia.com
Stig
Cisco System, Inc.
San Jose,
United States of America
Email: stig@cisco.com
Mankamana Mishra
Cisco System
Milpitas,
United States of America
Email: mankamis@cisco.com
Zhaohui Zhang
Juniper Networks
Boston,
United States of America
Email: zzhang@juniper.com
Mike
Futurewei Technologies Inc.
Santa Clara,
United States of America
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Email: michael.mcbride@futurewei.com
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