Network Working Group H. Bidgoli, Ed.
Internet-Draft Nokia
Intended status: Standards Track V. Voyer
Expires: January 28, 2021 Bell Canada
P. Parekh
Cisco System
Z. Zhang
Juniper Networks
July 27, 2020
P2MP Policy Ping
draft-hb-pim-p2mp-policy-ping-00
Abstract
SR P2MP policies are set of policies that enable architecture for
P2MP service delivery. A P2MP Policy consists of candidate paths
that connects the Root of the Tree to a set of Leaves. The P2MP
policy is composed of replication segments. A replication segment is
a forwarding instruction for a candidate path which is downloaded to
the Root, transit nodes and the leaves.
This document describes a simple and efficient mechanism that can be
used to detect data plane failures in P2MP Policy Candidate Paths
(CPs) and Path Instances (PIs).
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 January 28, 2021.
Bidgoli, et al. Expires January 28, 2021 [Page 1]
Internet-Draft P2MP Policy Ping July 2020
Copyright Notice
Copyright (c) 2020 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
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 . . . . . . . . . . . . . . 3
3. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.1. P2MP Policy Ping and Traceroute . . . . . . . . . . . . . 3
3.2. Packet format and new TLVs . . . . . . . . . . . . . . . 3
3.2.1. Identifying a P2MP Policy . . . . . . . . . . . . . . 4
3.2.1.1. P2MP Policy Sub-TLVs . . . . . . . . . . . . . . 4
3.3. Limiting the Scope of Response . . . . . . . . . . . . . 5
4. Operation of P2MP Policy Ping . . . . . . . . . . . . . . . . 5
4.1. Replication Segments Connected via a Unicast SR domain . 5
5. IANA Consideration . . . . . . . . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . 6
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
8.1. Normative References . . . . . . . . . . . . . . . . . . 6
8.2. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
Each P2MP Policy can have multiple CPs. The CP with highest
preference is the active CP while all other CPs are the backup CPs.
A CP can have multiple PI to allow global optimization of the CP via
Make Before Break procedures between the active PI and the newly
setup and optimized PI.
This document describes a mechanism that can be used to detect data
plane failures in P2MP Policy Candidate Paths (CP) and its associate
Path Instances (PI) from the root to a set of leaves.
Bidgoli, et al. Expires January 28, 2021 [Page 2]
Internet-Draft P2MP Policy Ping July 2020
This draft defines two new sub-TLVs to identifier a P2MP Policy and
reuses concepts from [RFC6425]
2. Conventions used in this document
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 RFC 2119 [RFC2119].
3. Motivation
A P2MP Policy and its corresponding Replication Segments are usually
setup via a PCE, after PCE has calculated the tree from the root to a
set of leaves. There is no underlay protocol to signal the P2MP
Policy from the root to the Leaf routers, as such when a P2MP tree
fails to deliver user traffic, the failure can be difficult to pin
point without a ping/traceroute mechanism to isolate the fault in the
P2MP tree. The P2MP Policy ping/traceroute can be utilize to detect
faults on the path of the tree and its associated replication
segments. These tools can be used to periodically ping the leaves to
ensure connectivity. If the ping fails, trace route can be initiated
to determine where the failure lies.
3.1. P2MP Policy Ping and Traceroute
The P2MP Policy Ping and Traceroute detect failure on the path of
P2MP Tree and its corresponding replication segments. Ping/
Traceroute packets are forwarded on the P2MP Policy, on a specific CP
or the CP's PI toward the leaf routers. They are replicated at the
replication point based on the replication segment information on the
corresponding transit node. The packet are processed accordingly
when their TTL expires or when the egress router (leaf) is reached.
The appropriate respond is send back to the root as per [RFC6425]
The implementation should take into account that there can be many CP
under the P2MP Policy, one active CP and many inactive CPs. The
implementation should allow each CP and its corresponding PIs to be
tested via Ping and Trace route. The Ping and Traceroute packet is
forwarded via that specific CP and its corresponding replication
segments.
3.2. Packet format and new TLVs
The packet format used is as per [RFC4379] section 3.
Bidgoli, et al. Expires January 28, 2021 [Page 3]
Internet-Draft P2MP Policy Ping July 2020
3.2.1. Identifying a P2MP Policy
The new sub-TLV identifiers are assigned, as follow:
artwork
Sub-Type Length Value Field
-------- ------ -----------
38 20 P2MP Policy IPv4 CP
39 32 P2MP Policy IPv6 CP
3.2.1.1. P2MP Policy Sub-TLVs
artwork
0 1 2 3
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address Family | Address Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Root Address (Cont.) ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TreeId length | Tree-ID ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Path-Instance length | Path-instance |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
o Address Family: Two-octet quantity containing a value from ADDRESS
FAMILY NUMBERS in [IANA-AF] that encodes the address family for
the Root LSR Address.
o Address Length: Length of the Root LSR Address in octets.
o Root Addrt: The address of Root node of P2MP tree instantiated by
the SR P2MP Policy
o TreeId Length: Length of the TreeID in octets. This should be set
to 4 octets
o Tree-ID: A identifier that is unique in context of the Root. This
is an unsigned 32-bit number.
o Path-instance Length: Length of the path instance ID in octet.
This should be set to 2.
Bidgoli, et al. Expires January 28, 2021 [Page 4]
Internet-Draft P2MP Policy Ping July 2020
o path-instance: path instance ID to be tested
3.3. Limiting the Scope of Response
As per [RFC6425] section 3.2 Four sub-TLVs are used for the inclusion
in the P2MP Responder Identifier TLV carried on the echo request
message.
The Sub-TLVs for IPv4 and IPv6 egress address P2MP responder is in
par with [RFC6425] section 3.2.1
The Sub-TLVs for IPv4 and IPv6 node address P2MP responder is in par
with [RFC6425] section 3.2.2
4. Operation of P2MP Policy Ping
The P2MP Policy Ping should be able to test the path for all the CPs
(active or inactive) or the CPs corresponding PIs for a P2MP policy
on the root router. In addition it should test all the Out going
interface for the replication segment connecting the root to the set
of leaves for this CP or PI. To do so the concepts in [RFC4379] and
[RFC6425] are extended to this draft.
The following sections will explain any new concepts for P2MP policy
Ping
4.1. Replication Segments Connected via a Unicast SR domain
Two replication segment can be connected via a unicast SR domain.
This means the traffic will be steered out of the upstream
replication segment based on the unicast SR SID List (as an example
node or adjacency SIDs). In this case the replication SID TTL is
subtracted by one on the current node. If the TTL hasn't expired,
the SR SID List will be placed on top of the replication segment,
with replication segment being at the bottom of the stack. The SR
SID List TTL should be set to 255, as an example pipe mode. When in
SR domain the TTL of SR SIDs will be decremented accordingly. The
TTL of the replication SID will be untouched in the SR domain. The
replication SID TTL will be examined again on the next replication
segment after the unicast SR SID List is removed from the label
stack. The appropriate actions will be taken on this replication
segment for P2MP Policy PING and Traceroute packet. To detect
failures in SR domain is beyond the scope of this draft.
Bidgoli, et al. Expires January 28, 2021 [Page 5]
Internet-Draft P2MP Policy Ping July 2020
5. IANA Consideration
Two new sub-TLV types are defined for inclusion within the LSP ping
[RFC4379] Target FEC Stack TLV (TLV type 1).
6. Security Considerations
TBD
7. Acknowledgments
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
8.2. Informative References
[draft-voyer-pim-sr-p2mp-policy]
"D. Yoyer, C. Filsfils, R.Prekh, H.bidgoli, Z. Zhang,
"draft-voyer-pim-sr-p2mp-policy"", October 2019.
[draft-voyer-spring-sr-replication-segment-04]
"D. Yoyer, C. Filsfils, R.Prekh, H.bidgoli, Z. Zhang,
"draft-voyer-pim-sr-p2mp-policy "draft-voyer-spring-sr-
replication-segment"", July 2020.
[RFC4379] "K. Kompella, G. Swallow", February 2006.
[RFC6425] "S. Saxena, G. Swallow, Z. Ali, A. Farrel, S. Yasukawa,
T.Nadeau "Detecting Data-Plane Failures in Point-to-
Multipoint MPLS"", November 2011.
Authors' Addresses
Hooman Bidgoli (editor)
Nokia
Ottawa
Canada
Email: hooman.bidgoli@nokia.com
Bidgoli, et al. Expires January 28, 2021 [Page 6]
Internet-Draft P2MP Policy Ping July 2020
Daniel Voyer
Bell Canada
Montreal
Canada
Email: daniel.yover@bell.ca
Rishabh Parekh
Cisco System
San Jose
USA
Email: riparekh@cisco.com
Zhaohui Zhang
Juniper Networks
Boston
USA
Email: zzhang@juniper.com
Bidgoli, et al. Expires January 28, 2021 [Page 7]