IP Performance Measurement Group Y. Wang
Internet-Draft T. Zhou
Intended status: Standards Track Huawei
Expires: January 11, 2021 July 10, 2020
Simple Two-way Active Measurement Protocol Extensions for Hop-by-Hop OAM
Data Collection
draft-wang-ippm-stamp-hbh-extensions-00
Abstract
This document defines optional TLVs which are carried in Simple Two-
way Active Measurement Protocol (STAMP) test packets to enhance the
STAMP base functions. Such extensions to STAMP enable OAM data
collection at every node that STAMP test packets traverse.
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.
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This Internet-Draft will expire on January 11, 2021.
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document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. TLV Extensions to STAMP . . . . . . . . . . . . . . . . . . . 3
3.1. IOAM Tracing Data TLV . . . . . . . . . . . . . . . . . . 3
3.2. Forward HbH Delay TLV . . . . . . . . . . . . . . . . . . 4
3.3. Backward HbH Delay TLV . . . . . . . . . . . . . . . . . 7
4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
5. Security Considerations . . . . . . . . . . . . . . . . . . . 9
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.1. Normative References . . . . . . . . . . . . . . . . . . 9
6.2. Informative References . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction
Simple Two-way Active Measurement Protocol (STAMP) enables the
measurement of both one-way and round-trip performance metrics, such
as delay, delay variation, and packet loss [RFC8762]. In the STAMP
session, the bidirectional packet flow is transmited between STAMP
Session-Sender and STAMP Session-Reflector. The STAMP Session-
Reflector receives packets transmited from Session-Sender and acts
according to the configuration. However, the performance of
intermediate nodes that STAMP test packets traverse are invisible.
And the STAMP instance must be configured at every intermediate node
to measure the performance per node that test packets traverse, which
increases the complexity of OAM in large-scale networks.
This document extents optional TLVs to STAMP which enable OAM data
collection at every node that STAMP test packets traverse, such as
measurement of delay, packet loss, delay variation per hop, and
record of route information. STAMP Extensions have defined several
optionnal TLVs to enhance the STAMP base functions. These optional
TLVs are defined as updates of the STAMP Optional Extensions
[I-D.ietf-ippm-stamp-option-tlv]. The following sections describe
the use of TLVs for STAMP that extend STAMP capability beyond its
base specification.
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2. Terminology
Following are abbreviations used in this document:
STAMP: Simple Two-way Active Measurement Protocol.
IOAM: In-situ OAM.
HbH: Hop-by-Hop.
3. TLV Extensions to STAMP
3.1. IOAM Tracing Data TLV
STAMP Session-Sender MAY place the IOAM Tracing Data TLV in STAMP
Session-Sender test packets to record the IOAM tracing data of every
IOAM capable node that the STAMP Session-Sender test packet traverses
in the forward path. As STAMP uses symmetrical packets, the Session-
Sender MUST set the Length value as a multiple of 4 octets according
to the number of intermediate nodes and the IOAM-Trace-Type (i.e. a
24-bit identifier which specifies which data types are used in the
node data list [I-D.ietf-ippm-ioam-data]). And the node-data-copied-
list fields MUST be set to zero upon Session-Sender test packets
transmission and ignored upon receipt.
The IOAM Tracing Data TLV has the following format:
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
+-------------------------------+-------------------------------+
| IOAM-Tracing-Data Type | Length |
+---------------------------------------------------------------+
| node data copied list [0] |
+---------------------------------------------------------------+
| node data copied list [1] |
+---------------------------------------------------------------+
~ ... ~
+---------------------------------------------------------------+
| node data copied list [n] |
+---------------------------------------------------------------+
Fig. 1 IOAM Tracing Data TLV Format
where fields are defined as the following:
IOAM-Tracing-Data Type: To be assigned by IANA.
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Length: A 2-octet field that indicates the length of the value field
in octets and equal to a multiple of 4 octets dependent on the number
of nodes and IOAM-Trace-Type bits.
node data copied list [0..n]: A variable-length field, which record
the copied content of each node data element determined by the IOAM-
Trace-Type. The order of packing the data fields in each node data
element follows the bit order of the IOAM-Trace-Type field (see
section 4.4.1 of [I-D.ietf-ippm-ioam-data]). The last node data
element in this list is the node data of the first IOAM trace capable
node in the path.
In an IOAM domain, the STAMP Session-Sender and the STAMP Session-
Reflector MAY be configured as the IOAM encapsulating node and the
IOAM decapsulating node. The STAMP Session-Sender (i.e. the IOAM
encapsulating node) generates the STAMP test packet with the IOAM
Tracing Data TLV. For applying the IOAM Trace-Option functionalities
to the STAMP Session-Sender test packet, the STAMP Session-Sender
must inserts the "trace option header" and allocate an node-data-list
array [I-D.ietf-ippm-ioam-data] into "option data" fields of Hop-by-
Hop Options header in IPv6 packets [I-D.ietf-ippm-ioam-ipv6-options],
and sets the corresponding bits in the IOAM-Trace-Type. Also, the
STAMP Session-Sender allocates an node-data-list array which is used
to store OAM data retrieved from every IOAM transit nodes while the
Session-Sender test packets traverse the path.
When the STAMP Session-Reflector (i.e. the IOAM decapsulating node)
received the STAMP Session-Sender test packet with the IOAM-Tracing-
Data TLV, it MUST copy the node-data-list array into the node-data-
copied-list array carried in the reflected test packet before
transmission and MUST remove the IOAM-Data-Fields. Hence, using
IOAM-Tracing-Data TLV in STAMP testing enables hop-by-hop OAM data
collection.
Also the STAMP Session-Reflector MAY be configured as IOAM
encapsulating node to apply the IOAM Trace-Option functionalities to
the reflected test packet. Hence, hop-by-hop OAM data collection can
be also enabled for the backward path that the reflected packets
traverse. When the reflected packet arrives at the Session-Sender
receives, it can be either locally processed or sent to the
centralized controller.
3.2. Forward HbH Delay TLV
STAMP Session-Sender MAY place the Forward HbH Delay TLV in Session-
Sender test packets to record the ingress timestamp and engress
timestamp at every intermediate nodes in the forward path that STAMP
test packets traverse. The Session-Sender MUST set the Length value
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according to the number of intermediate nodes in the forward path and
the timestamp formats. There are several methods to synchronize the
clock, e.g., Network Time Protocol (NTP) [RFC5905]. For example, if
a 64-bit timestamp format defined in NTP is used, the Length value
MUST be set as a multiple of 8 octets. The Timestamp Tuple list
(Ingress Timestamp [0..n], Engress Timestamp [0..n]) fields MUST be
set to zero upon Session-Sender test packets transmission and ignored
upon receipt.
The Forward HbH Delay TLV has the following format:
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
+-------------------------------+---------------+---------------+
| Forward HbH Delay Type | Length | Node Left |
+-------------------------------+---------------+---------------+
| Ingress Timestamp [0] |
| |
+---------------------------------------------------------------+
| Engress Timestamp [0] |
| |
+---------------------------------------------------------------+
~ ... ~
+---------------------------------------------------------------+
| Ingress Timestamp [n] |
| |
+---------------------------------------------------------------+
| Engress Timestamp [n] |
| |
+---------------------------------------------------------------+
Fig. 2 Forward HbH Delay TLV Format
where fields are defined as the following:
Forward HbH Delay Type: To be assigned by IANA.
Length: A 8-bit field that indicates the length of the value portion
in octets and MUST be a multiple of 8 octets according to the number
of intermediate nodes in the forward path.
Node Left: A 8-bit unsigned integer, which indicates the number of
intermediate nodes remaining. That is, number of exlicitly listed
intermediate nodes still to be visited before reaching the
destination node in the forward path. The Node Left field is set to
n-1, where n is the number of intermediate nodes.
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Timestamp Tuple list (Ingress Timestamp [0..n], Engress Timestamp
[0..n]): A variable-length field, which record the timestamp when the
Session-Sender test packet is received at the ingress of the n-th
intermediate node and the timestamp when the Session-Sender test
packet is sent at engress of the n-th intermediate node. For
example, if a 64-bit timestamp format defined in NTP is used, the
length of each Timestamp tuple (Ingress Timestamp [n], Engress
Timestamp [n]) must be 16 octets. The Timestamp Tuple list is
encoded starting from the last intermediate node which is exlicitly
listed. That is, the first element of the Timestamp Tuple (Ingress
Timestamp [0], Engress Timestamp [0]) records the timestamps when the
Session-Sender test packet received and forwarded at the last
intermediate node of a explicit path, the second element records the
penultimate Timestamp Tuple when the Session-Sender test packet
received and forwarded at the penultimate intermediate node of a
explicit path, and so on.
In the following reference topology, Node N1, N2, N3, N4 and N5 are
SRv6 capable nodes. Node N1 is the STAMP Session-Sender and Node N5
is the STAMP Session-Reflector. T1 is the Timestamp taken by the
Session-Sender (i.e. N1) at the start of transmitting the test
packet. T2 is the Receive Timestamp when the test packet was
received by the Session-Reflector (i.e. N5). T3 is the Timestamp
taken by the Session-Reflector at the start of transmitting the test
packet. T4 is the Receive Timestamp when the test packet was
received by the Session-Sender. Timestamp tuples (t1,t2), (t3,t4)
and (t5,t6) are the timestamps when the test packet received and
transmited by sequence of intermediate nodes in the forward path.
Timestamp Tuples (t7,t8), (t9,t10) and (t11,t12) are the timestamps
when the test packet received and transmited by sequence of
intermediate nodes in the backward path.
====== ====== ====== ====== ======
| | T1--->t1 | | t2--->t3 | | t4--->t5 | | t6--->T2| |
| N1 |==========| N2 |==========| N3 |==========| N4 |=========| N5 |
| | T4<---t12| |t11<---t10| | t9<---t8 | | t7<---T3| |
====== ====== ====== ====== ======
Fig. 3 Reference Topology
The STAMP Session-Sender (i.e. Node N1) generates the STAMP test
packet with the Forward HbH Delay TLV. When an intermediate node
receives the STAMP test packet, the node sends the packet to control
plane and fills the Ingress Timestamp [n] filed in the Forward HbH
Delay TLV. Then the time taken by the intermediate node transmitting
the test packet is recorded in to Engress Timestamp [n] field in the
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Forward HbH Delay TLV. The mechanism of timestamping and punting
packet to control plane is outside the scope of this specification.
When the STAMP Session-Reflector received the test packet with the
Forward HbH Delay TLV, it MUST copy the Forward HbH Delay TLV into
the reflected test packet before its transmission. Using Forward HbH
Delay TLV in STAMP testing enables hop-by-hop delay measurement in
the forward path.
3.3. Backward HbH Delay TLV
STAMP Session-Sender MAY place the Backward HbH Delay TLV in Session-
Sender test packets to record the ingress timestamp and engress
timestamp when Session-Reflector test packets are received and sent
at every intermediate nodes in the backward path. The Session-Sender
MUST set the Length value according to the number of intermediate
nodes in the backward path and the timestamp formats. There are
several methods to synchronize the clock, e.g., Network Time Protocol
(NTP) [RFC5905]. For example, if a 64-bit timestamp format defined
in NTP is used, the Length value MUST be set as a multiple of 8
octets. The Timestamp Tuple list (Ingress Timestamp [0..n], Engress
Timestamp [0..n]) fields MUST be set to zero upon Session-Sender test
packets transmission and ignored upon receipt.
The Backward HbH Delay TLV has the following format:
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
+-------------------------------+---------------+---------------+
| Backward HbH Delay Type | Length | Node Left |
+-------------------------------+---------------+---------------+
| Ingress Timestamp [0] |
| |
+---------------------------------------------------------------+
| Engress Timestamp [0] |
| |
+---------------------------------------------------------------+
~ ... ~
+---------------------------------------------------------------+
| Ingress Timestamp [n] |
| |
+---------------------------------------------------------------+
| Engress Timestamp [n] |
| |
+---------------------------------------------------------------+
Fig. 4 Backward HbH Delay TLV Format
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where fields are defined as the following:
Backward HbH Delay Type: To be assigned by IANA.
Length: A 8-bit field that indicates the length of the value portion
in octets and will be a multiple of 8 octets dependent on the number
of nodes in a path.
Node Left: A 8-bit unsigned integer, which indicates the number of
intermediate nodes remaining. That is, number of exlicitly listed
intermediate nodes still to be visited before reaching the
destination node in the backward path. The Node Left field is set to
n-1, where n is the number of intermediate nodes.
Timestamp Tuple list (Ingress Timestamp [0..n], Engress Timestamp
[0..n]): A variable-length field, which record the timestamp when the
reflected test packet is received at the ingress of the n-th
intermediate node and the timestamp when the reflected test packet is
sent at engress of the n-th intermediate node. For example, if a
64-bit timestamp format defined in NTP is used, the length of each
Timestamp tuple (Ingress Timestamp [n], Engress Timestamp [n]) must
be 16 octets. The Timestamp Tuple list is encoded starting from the
last intermediate node which is exlicitly listed. That is, the first
element of the Timestamp Tuple (Ingress Timestamp [0], Engress
Timestamp [0]) records the timestamps when the reflected test packet
received and forwarded at the last intermediate node of a explicit
path, the second element records the penultimate Timestamp Tuple when
the reflected test packet received and forwarded at the penultimate
intermediate node of a explicit path, and so on.
When the STAMP Session-Reflector received the Session-Sender test
packet with the Backward HbH Delay TLV, it MUST copy the Backward HbH
Delay TLV into the reflected test packet.
When an intermediate node receives the reflected test packet, the
node sends the packet to control plane and fills the Ingress
Timestamp [n] filed of Backward HbH Delay TLV. Then the time taken
by the intermediate node transmitting the test packet is recorded in
to Engress Timestamp [n] field of Backward HbH Delay TLV. Using
Backward HbH Delay TLV in STAMP testing enables hop-by-hop delay
measurement in the backward path.
4. IANA Considerations
IANA is requested to allocate values for the following TLV Type from
the "STAMP TLV Type" registry [I-D.ietf-ippm-stamp-option-tlv].
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+------------+------------------------+---------------+
| Code Point | Description | Reference |
+------------+------------------------+---------------+
| TBA1 | IOAM Tracing Data TLV | This document |
| TBA2 | Forward HBH Delay TLV | This document |
| TBA3 | Backward HBH Delay TLV | This document |
+------------+------------------------+---------------+
5. Security Considerations
This document introduces new TLV extensions to STAMP. It does not
introduce any new security risks to STAMP.
6. References
6.1. Normative References
[I-D.ietf-ippm-ioam-data]
"Data Fields for In-situ OAM",
<https://datatracker.ietf.org/doc/draft-ietf-ippm-ioam-
data/>.
[I-D.ietf-ippm-ioam-ipv6-options]
"In-situ OAM IPv6 Options",
<https://datatracker.ietf.org/doc/draft-ietf-ippm-ioam-
ipv6-options/>.
[I-D.ietf-ippm-stamp-option-tlv]
"Simple Two-way Active Measurement Protocol Optional
Extensions", <https://datatracker.ietf.org/doc/draft-ietf-
ippm-stamp-option-tlv/>.
[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>.
[RFC8762] "Simple Two-Way Active Measurement Protocol",
<https://datatracker.ietf.org/doc/rfc8762/>.
6.2. Informative References
[RFC5905] "Network Time Protocol Version 4: Protocol and Algorithms
Specification", <https://www.rfc-editor.org/info/rfc5905>.
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Authors' Addresses
Yali Wang
Huawei
156 Beiqing Rd., Haidian District
Beijing
China
Email: wangyali11@huawei.com
Tianran Zhou
Huawei
156 Beiqing Rd., Haidian District
Beijing
China
Email: zhoutianran@huawei.com
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