Routing Working Group A. Mishra
Internet-Draft M. Jethanandani
Intended status: Standards Track A. Saxena
Expires: April 23, 2015 Ciena Corporation
S. Pallagatti
Juniper Networks
M. Chen
Huawei
October 20, 2014
BFD Stability
draft-ashesh-bfd-stability-01.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 <xref
target="RFC2119">RFC 2119</xref>.
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
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Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 23, 2015.
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Copyright Notice
Copyright (c) 2014 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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. BFD Null-Authentication TLV . . . . . . . . . . . . . . . . . 2
3. Theory of Operations . . . . . . . . . . . . . . . . . . . . 3
4. IANA Requirements . . . . . . . . . . . . . . . . . . . . . . 4
5. Security Consideration . . . . . . . . . . . . . . . . . . . 4
6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
7. Normative References . . . . . . . . . . . . . . . . . . . . 4
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4
1. Introduction
The Bidirectional Forwarding Detection (BFD) 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 (the Detection Time as described in RFC 5880)
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 with the ability to
measure the stability of BFD sessions and provides data to the
operators.
2. BFD Null-Authentication TLV
The functionality proposed for BFD stability measurement is achieved
by appending the Null-Authentication TLV to the BFD control frame.
The Null-Authentication TLV (called 0-Auth in this document) extends
the existing BFD Authentication TLV structure by adding a new Auth-
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Type of <IANA Assigned>. This TLV carries the Sequence Number for
frame loss measurement.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Auth Type | Auth Len | Auth Key ID | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved for Future |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Reserved for Future |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
where:
Auth Type: The Authentication Type, which in this case is <IANA
assigned> (Null Authentication).
Auth Len: The length of the Authentication Section, in bytes. Set to
12.
Auth Key ID: The Authentication Key ID in use for this packet. This
MUST be set to zero on transmit, and ignored on receipt.
Reserved: This byte MUST be set to zero on transmit, and ignored on
receipt.
Reserved for Future: For future extensions. MUST be set to 0 if not
used.
Sequence Number: This indicates the sequence number for this packet
and MUST be present in every 0-Auth TLV. This value is incremented
by 1 for every frame transmitted while the session state is UP. A
value of 0 indicates a request by sender to reset the sequence number
correlation logic at the receiver. The first frame transmitted by
the sender MAY set this field to 0.
3. Theory of Operations
This mechanism allows operator to measure the loss of BFD CC frames.
This measurement counts the number of BFD control frames missed at
the receiver due to a transient change in the network such as
congestion. Frame-loss is detected by comparing the Sequence Number
field in the 0-Auth TLV in successive BFD CC frames. The Sequence
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Number in each successive control frame generated on a BFD session by
the transmitter is incremented by one.
The first BFD Loss-Delay 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.
4. IANA Requirements
IANA is requested to assign new Auth-Type for the Null-Authentication
TLV for BFD Stability Measurement. The following number is
suggested.
Value Meaning
6 Null-Authentication TLV
5. Security Consideration
Since this method uses an authentication TLV to achive the
functionality, usage of this TLV will prevent the use of other
authentication TLVs.
6. Acknowledgements
Nobo Akiya, Jeffery Haas, Peng Fan, Dileep Singh, Basil Saji, Sagar
Soni and Mallik Mudigonda also conributed to this document.
7. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD)", RFC 5880, June 2010.
Authors' Addresses
Ashesh Mishra
Ciena Corporation
3939 North 1st Street
San Jose, CA 95134
USA
Email: mishra.ashesh@gmail.com
URI: www.ciena.com
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Mahesh Jethanandani
Ciena Corporation
3939 North 1st Street
San Jose, CA 95134
USA
Email: mjethanandani@gmail.com
URI: www.ciena.com
Ankur Saxena
Ciena Corporation
3939 North 1st Street
San Jose, CA 95134
USA
Email: ankurpsaxena@gmail.com
Santosh Pallagatti
Juniper Networks
Juniper Networks, Exora Business Park
Bangalore, Karnataka 560103
India
Phone: +
Email: santoshpk@juniper.net
Mach Chen
Huawei
Email: mach.chen@huawei.com
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