Internet DRAFT - draft-ashesh-bfd-stability
draft-ashesh-bfd-stability
Routing Working Group A. Mishra
Internet-Draft Ciena Corporation
Intended status: Standards Track M. Jethanandani
Expires: July 30, 2017 Cisco Systems
A. Saxena
Ciena Corporation
S. Pallagatti
Juniper Networks
M. Chen
Huawei
P. Fan
China Mobile
January 26, 2017
BFD Stability
draft-ashesh-bfd-stability-05.txt
Abstract
This document describes extensions to the Bidirectional Forwarding
Detection (BFD) protocol to measure BFD stability. Specifically, it
describes a mechanism for detection of BFD frame loss.
Requirements Language
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].
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 http://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 July 30, 2017.
Mishra, et al. Expires July 30, 2017 [Page 1]
Internet-Draft BFD Stability January 2017
Copyright Notice
Copyright (c) 2017 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
(http://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. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. BFD Null-Authentication TLV . . . . . . . . . . . . . . . . . 3
4. Theory of Operations . . . . . . . . . . . . . . . . . . . . 3
4.1. Loss Measurement . . . . . . . . . . . . . . . . . . . . 3
5. IANA Requirements . . . . . . . . . . . . . . . . . . . . . . 4
6. Security Consideration . . . . . . . . . . . . . . . . . . . 4
7. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 4
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
9. Normative References . . . . . . . . . . . . . . . . . . . . 4
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4
1. Introduction
The Bidirectional Forwarding Detection (BFD) [RFC5880] protocol
operates by transmitting and receiving control frames, generally at
high frequency, over the datapath being monitored. In order to
prevent significant data loss due to a datapath failure, the
tolerance for lost or delayed frames in the Detection Time, as
defined in BFD [RFC5880] is set to the smallest feasible value.
This document proposes a mechanism to detect lost frames in a BFD
session in addition to the datapath fault detection mechanisms of
BFD. Such a mechanism presents significant value to measure the
stability of BFD sessions and provides data to the operators for the
cause of a BFD failure.
This document does not propose BFD extension to measure data traffic
loss or delay on a link or tunnel and the scope is limited to BFD
frames.
Mishra, et al. Expires July 30, 2017 [Page 2]
Internet-Draft BFD Stability January 2017
2. Use Cases
Legacy BFD cannot detect any BFD frame loss if loss does not last for
dead interval. This draft proposes a method to detect a dropped
frame on the receiver. For example, if the receiver receives BFD CC
frame k at time t but receives frame k+3 at time t+10ms, and never
receives frame k+1 and/or k+2, then it has experienced a drop.
This proposal enables BFD engine to generate diagnostic information
on the health of each BFD session that could be used to preempt a
failure on a link that BFD was monitoring by allowing time for a
corrective action to be taken.
In a faulty datapath scenario, operator can use BFD health
information to trigger delay and loss measurement OAM protocol
(Connectivity Fault Management (CFM) or Loss Measurement (LM)-Delay
Measurement (DM)) to further isolate the issue.
3. BFD Null-Authentication TLV
The functionality proposed for BFD stability measurement is achieved
by appending the Null-Authentication TLV (as defined in Optimizing
BFD Authentication [I-D.ietf-bfd-optimizing-authentication] ) to the
BFD control frame that do not have authentication enabled.
4. Theory of Operations
This mechanism allows operator to measure the loss of BFD CC frames.
When using MD5 or SHA authentication, BFD uses authentication TLV
that carries the Sequence Number. However, if non-meticulous
authentication is being used, or no authentication is in use, then
the non-authenticated BFD frames MUST include NULL-Auth TLV.
4.1. Loss Measurement
Loss measurement counts the number of BFD control frames missed at
the receiver during any Detection Time period. The loss is detected
by comparing the Sequence Number field in the Auth TLV (NULL or
otherwise) in successive BFD CC frames. The Sequence Number in each
successive control frame generated on a BFD session by the
transmitter is incremented by one.
The first BFD NULL-Auth TLV processed by the receiver that has a non-
zero sequence number is used for bootstrapping the logic. Each
successive frame after this is expected to have a Sequence Number
that is one greater than the Sequence Number in the previous frame.
Mishra, et al. Expires July 30, 2017 [Page 3]
Internet-Draft BFD Stability January 2017
When the Sequence Number wraps around it should start from 1 instead
of 0.
5. IANA Requirements
N/A
6. Security Consideration
Other than concerns raised in BFD [RFC5880] there are no new concerns
with this proposal.
7. Contributors
Manav Bhatia
8. Acknowledgements
Authors would like to thank Nobo Akiya, Jeffery Haas, Peng Fan,
Dileep Singh, Basil Saji, Sagar Soni and Mallik Mudigonda who also
contributed to this document.
9. Normative References
[I-D.ietf-bfd-optimizing-authentication]
Jethanandani, M., Mishra, A., Saxena, A., and M. Bhatia,
"Optimizing BFD Authentication", draft-ietf-bfd-
optimizing-authentication-02 (work in progress), January
2017.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010,
<http://www.rfc-editor.org/info/rfc5880>.
Authors' Addresses
Mishra, et al. Expires July 30, 2017 [Page 4]
Internet-Draft BFD Stability January 2017
Ashesh Mishra
Ciena Corporation
3939 North 1st Street
San Jose, CA 95134
USA
Email: mishra.ashesh@outlook.com
URI: www.ciena.com
Mahesh Jethanandani
Cisco Systems
170 W. Tasman Drive
San Jose, CA 95134
USA
Email: mjethanandani@gmail.com
URI: www.cisco.com
Ankur Saxena
Ciena Corporation
3939 North 1st Street
San Jose, CA 95134
USA
Email: ankurpsaxena@gmail.com
URI: www.ciena.com
Santosh Pallagatti
Juniper Networks
Juniper Networks, Exora Business Park
Bangalore, Karnataka 560103
India
Email: santoshpk@juniper.net
Mach Chen
Huawei
Email: mach.chen@huawei.com
Mishra, et al. Expires July 30, 2017 [Page 5]
Internet-Draft BFD Stability January 2017
Peng Fan
China Mobile
32 Xuanwumen West Street
Beijing, Beijing
China
Email: fanp08@gmail.com
Mishra, et al. Expires July 30, 2017 [Page 6]
