Hi Dan,
thank you for your review, detailed questions, and helpful suggestions. Please find my answers and notes below tagged GIM>>.
Regards,
Greg
On Mon, Jun 29, 2020 at 8:02 AM Dan Romascanu via Datatracker <noreply@xxxxxxxx> wrote:
Reviewer: Dan Romascanu
Review result: Ready with Issues
I am the assigned Gen-ART reviewer for this draft. The General Area
Review Team (Gen-ART) reviews all IETF documents being processed
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For more information, please see the FAQ at
<https://trac.ietf.org/trac/gen/wiki/GenArtfaq>.
Document: draft-ietf-ippm-stamp-option-tlv-06
Reviewer: Dan Romascanu
Review Date: 2020-06-29
IETF LC End Date: 2020-07-06
IESG Telechat date: Not scheduled for a telechat
Summary: Ready with issues
This is a clear, well-written document. There are a few minor issues that would
benefit from clarifications and possible edits before approval.
Major issues:
Minor issues:
1. Section 3. Is there any recommended strategy to generate SSIDs? Are these
supposed to be generated sequentially? Randomly? How soon is the 16 -bit space
supposed to wrap-up? Some clarification would be useful I believe.
GIM>> Because test sessions, in general, will be performed for different periods of time, implementation will need to manage the pool of available identifiers. I agree, the initial allocation may use sequential ascending increment by one method, but at some point, it will be "get-the-next-available number". I propose to update the text as follows:
OLD TEXT:
A STAMP
Session-Sender MAY generate a locally unique STAMP Session Identifier
(SSID). SSID is two octets long non-zero unsigned integer.
NEW TEXT:
A STAMP
Session-Sender MAY generate a locally unique STAMP Session Identifier
(SSID). SSID is two octets long non-zero unsigned integer. SSID generation
policy is implementation-specific. For example, sequentially ascending
incremented by one method could be used for the initial allocation of SSID.
Because of test sessions lasting different time an implementation that uses
SSID MUST monitor the pool of available identifiers. An implementation
SHOULD NOT assign the same identifier to different STAMP test sessions.
A STAMP
Session-Sender MAY generate a locally unique STAMP Session Identifier
(SSID). SSID is two octets long non-zero unsigned integer.
NEW TEXT:
A STAMP
Session-Sender MAY generate a locally unique STAMP Session Identifier
(SSID). SSID is two octets long non-zero unsigned integer. SSID generation
policy is implementation-specific. For example, sequentially ascending
incremented by one method could be used for the initial allocation of SSID.
Because of test sessions lasting different time an implementation that uses
SSID MUST monitor the pool of available identifiers. An implementation
SHOULD NOT assign the same identifier to different STAMP test sessions.
2. Section 4.5 - how is the value Session-Sender Tx counter (S_TxC) determined
by the sender?
GIM>> The value of S_TxC is the current value of the transmitted in-profile packets. Would the following update (also addressing the #3) make it clearer?
OLD TEXT:
o Session-Sender Tx counter (S_TxC) is four octets long field.
o Session-Reflector Rx counter (R_RxC) is four octets long field.
MUST be zeroed by the Session-Sender and filled by the Session-
Reflector.
o Session-Reflector Tx counter (R_TxC) is four octets long field.
MUST be zeroed by the Session-Sender and filled by the Session-
Reflector.
NEW TEXT:
o Session-Sender Tx counter (S_TxC) is four octets long field. The
Session-Reflector MUST set its value equal to the number of the
transmitted in-profile packets..
o Session-Reflector Rx counter (R_RxC) is four octets long field.
MUST be zeroed by the Session-Sender on transmit and ingored by
the Session-Reflector on receipt. The Session-Reflector MUST fill
it with the value of in-profile packets received.
o Session-Reflector Tx counter (R_TxC) is four octets long field.
MUST be zeroed by the Session-Sender and ignored by the Session-
Reflector on receipt. The Session-Reflector MUST fill with the
value of the transmitted in-profile packets.
Session-Reflector MUST set its value equal to the number of the
transmitted in-profile packets..
o Session-Reflector Rx counter (R_RxC) is four octets long field.
MUST be zeroed by the Session-Sender on transmit and ingored by
the Session-Reflector on receipt. The Session-Reflector MUST fill
it with the value of in-profile packets received.
o Session-Reflector Tx counter (R_TxC) is four octets long field.
MUST be zeroed by the Session-Sender and ignored by the Session-
Reflector on receipt. The Session-Reflector MUST fill with the
value of the transmitted in-profile packets.
3. Section 4.5 - (R_RxC) and (R_TxC) MUST be zeroed by the Session-Sender - Is
this verified at reception? What happens if a Session-Reflector detects a
non-zero value in one of these fields?
GIM>> Please let us know if the update above addresses your concern.
4. Section 4.6 - it seems that understanding [TS23501] is needed to properly
implement this section and interpret the content of the TLV. Should not this
reference be Normative rather than Informative?
GIM>> Agreed and moved it to the list of Normative References
5. Section 5.2 - as the values for Synchronization Sources in Table 4 refer to
'this document', it seems to be necessary to include in this document
references to the documents that define the respective terms / sources
GIM>> The only convenient place for references I see is in the Acronyms section. Would you suggest another section in the document? Besides the location, some of the listed sources of synchronization do not have a standard specification, e.g. BITS/SSU, or the specification is not easily available, e.g., Russian government's GLONASS. Some systems, like LORAL-C, are in the process of being decommissioned and only a few LORAL transmitters remain operational. Would adding references to NTP and PTP in the Acronyms section be acceptable?
BITS Building Integrated Timing Supply
CoS Class of Service
DSCP Differentiated Services Code Point
ECN Explicit Congestion Notification
GLONASS Global Orbiting Navigation Satellite System
GPS Global Positioning System [GPS]
HMAC Hashed Message Authentication Code
LORAN-C Long Range Navigation System Version C
MBZ Must Be Zero
NTP Network Time Protocol [RFC5905]
PMF Performance Measurement Function
PTP Precision Time Protocol [IEEE.1588.2008]
TLV Type-Length-Value
SSID STAMP Session Identifier
SSU Synchronization Supply Unit
STAMP Simple Two-way Active Measurement Protocol
CoS Class of Service
DSCP Differentiated Services Code Point
ECN Explicit Congestion Notification
GLONASS Global Orbiting Navigation Satellite System
GPS Global Positioning System [GPS]
HMAC Hashed Message Authentication Code
LORAN-C Long Range Navigation System Version C
MBZ Must Be Zero
NTP Network Time Protocol [RFC5905]
PMF Performance Measurement Function
PTP Precision Time Protocol [IEEE.1588.2008]
TLV Type-Length-Value
SSID STAMP Session Identifier
SSU Synchronization Supply Unit
STAMP Simple Two-way Active Measurement Protocol
6. Section 6 - Security Considerations: Is not sending of test packets to a
reflector that does not support SSID a potential sourse for DoS attacks?
GIM>> A Session-Reflector that does not support SSID would transmit reflected test packet with SSID field zeroed. The local to the Session-Sender policy will control whether the Session-Sender stops or continues the test session.
Same
question about sending packets with unsupported TLV types. How do Reflectors
protect against such situations? As such attacks would be beyond STAMP base
specifications, it may be good to discuss these.
GIM>> A Session-Reflector that does not support STAMP extensions is not expected to compare the value in the Length field of the UDP header and the length of the STAMP base packet. Hence the Session-Reflector will transmit the base STAMP packet. It is the local policy on the Session-Sender (similar to the handling of SSID == 0 situation) that will control the Sender's behavior. I think the text might be appended to the second paragraph of Section 4. The updated paragraph is below:
A STAMP node, whether Session-Sender or Session-Reflector, receiving
a test packet MUST determine whether the packet is a base STAMP
packet or includes one or more TLVs. The node MUST compare the value
in the Length field of the UDP header and the length of the base
STAMP test packet in the mode, unauthenticated or authenticated based
on the configuration of the particular STAMP test session. If the
difference between the two values is larger than the length of UDP
header, then the test packet includes one or more STAMP TLVs that
immediately follow the base STAMP test packet. A Session-Reflector
that does not support STAMP extensions is not expected to compare the
value in the Length field of the UDP header and the length of the
STAMP base packet. Hence the Session-Reflector will transmit the
base STAMP packet. It is the local policy on the Session-Sender
(similar to the handling of SSID == 0 scenario described in
Section 3) that will control the sender's behavior.
a test packet MUST determine whether the packet is a base STAMP
packet or includes one or more TLVs. The node MUST compare the value
in the Length field of the UDP header and the length of the base
STAMP test packet in the mode, unauthenticated or authenticated based
on the configuration of the particular STAMP test session. If the
difference between the two values is larger than the length of UDP
header, then the test packet includes one or more STAMP TLVs that
immediately follow the base STAMP test packet. A Session-Reflector
that does not support STAMP extensions is not expected to compare the
value in the Length field of the UDP header and the length of the
STAMP base packet. Hence the Session-Reflector will transmit the
base STAMP packet. It is the local policy on the Session-Sender
(similar to the handling of SSID == 0 scenario described in
Section 3) that will control the sender's behavior.
Nits/editorial comments:
1. Section 2.1 - it's more convenient for future users of the document if
acronyms were listed in alphabetical order
GIM>> Agree. Done (please check it above).
2. Sections 4.6, 4.7 - inconsistent use of capitalization:
Reserved - ... must be zeroed on transmission
and ignored on receipt.
It's a 'must' in 4.6, and a 'MUST' in 4.7
GIM>> Thank you for pointing it out. I've found two cases of "must" that changed to normative-style.
Network Working Group G. Mirsky
Internet-Draft X. Min
Updates: 8762 (if approved) ZTE Corp.
Intended status: Standards Track H. Nydell
Expires: January 3, 2021 Accedian Networks
R. Foote
Nokia
A. Masputra
Apple Inc.
E. Ruffini
OutSys
July 2, 2020
Simple Two-way Active Measurement Protocol Optional Extensions
draft-ietf-ippm-stamp-option-tlv-07
Abstract
This document describes optional extensions to Simple Two-way Active
Measurement Protocol (STAMP) which enable measurement performance
metrics in addition to ones supported by the STAMP base
specification. The document also defines a STAMP Test Session
Identifier and thus updates RFC 8762.
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 3, 2021.
Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved.
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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
2.1. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2. Requirements Language . . . . . . . . . . . . . . . . . . 3
3. STAMP Test Session Identifier . . . . . . . . . . . . . . . . 4
4. TLV Extensions to STAMP . . . . . . . . . . . . . . . . . . . 8
4.1. Extra Padding TLV . . . . . . . . . . . . . . . . . . . . 11
4.2. Location TLV . . . . . . . . . . . . . . . . . . . . . . 11
4.3. Timestamp Information TLV . . . . . . . . . . . . . . . . 13
4.4. Class of Service TLV . . . . . . . . . . . . . . . . . . 14
4.5. Direct Measurement TLV . . . . . . . . . . . . . . . . . 15
4.6. Access Report TLV . . . . . . . . . . . . . . . . . . . . 17
4.7. Follow-up Telemetry TLV . . . . . . . . . . . . . . . . . 18
4.8. HMAC TLV . . . . . . . . . . . . . . . . . . . . . . . . 20
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
5.1. STAMP TLV Registry . . . . . . . . . . . . . . . . . . . 21
5.2. STAMP TLV Flags Sub-registry . . . . . . . . . . . . . . 22
5.3. Synchronization Source Sub-registry . . . . . . . . . . . 22
5.4. Timestamping Method Sub-registry . . . . . . . . . . . . 23
5.5. Return Code Sub-registry . . . . . . . . . . . . . . . . 24
6. Security Considerations . . . . . . . . . . . . . . . . . . . 25
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 25
8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 25
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 25
9.1. Normative References . . . . . . . . . . . . . . . . . . 26
9.2. Informative References . . . . . . . . . . . . . . . . . 26
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 27
1. Introduction
Simple Two-way Active Measurement Protocol (STAMP) [RFC8762] supports
the use of optional extensions that use Type-Length-Value (TLV)
encoding. Such extensions enhance the STAMP base functions, such as
measurement of one-way and round-trip delay, latency, packet loss,
and the ability to detect packet duplication and out-of-order
delivery of the test packets. This specification defines optional
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STAMP extensions, their formats, and the theory of operation. Also,
a STAMP Test Session Identifier is defined as an update of the base
STAMP specification [RFC8762].
2. Conventions Used in This Document
2.1. Acronyms
BDS BeiDou Navigation Satellite System
BITS Building Integrated Timing Supply
CoS Class of Service
DSCP Differentiated Services Code Point
ECN Explicit Congestion Notification
GLONASS Global Orbiting Navigation Satellite System
GPS Global Positioning System [GPS]
HMAC Hashed Message Authentication Code
LORAN-C Long Range Navigation System Version C
MBZ Must Be Zero
NTP Network Time Protocol [RFC5905]
PMF Performance Measurement Function
PTP Precision Time Protocol [IEEE.1588.2008]
TLV Type-Length-Value
SSID STAMP Session Identifier
SSU Synchronization Supply Unit
STAMP Simple Two-way Active Measurement Protocol
2.2. Requirements Language
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
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14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. STAMP Test Session Identifier
STAMP Session-Sender transmits test packets to STAMP Session-
Reflector. STAMP Session-Reflector receives Session-Sender's packet
and acts according to the configuration and optional control
information communicated in the Session-Sender's test packet. STAMP
defines two different test packet formats, one for packets
transmitted by the STAMP-Session-Sender and one for packets
transmitted by the STAMP-Session-Reflector. STAMP supports two
modes: unauthenticated and authenticated. Unauthenticated STAMP test
packets are compatible on the wire with unauthenticated TWAMP-Test
[RFC5357] packet formats.
By default, STAMP uses symmetrical packets, i.e., the size of the
packet transmitted by Session-Reflector equals the size of the packet
received by the Session-Reflector.
A STAMP Session is identified using 4-tuple (source and destination
IP addresses, source and destination UDP port numbers). A STAMP
Session-Sender MAY generate a locally unique STAMP Session Identifier
(SSID). SSID is two octets long non-zero unsigned integer. A
Session-Sender MAY use SSID to identify a STAMP test session. If
SSID is used, it MUST be present in each test packet of the given
test session. In the unauthenticated mode, SSID is located, as
displayed in Figure 1.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Estimate | SSID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| |
| MBZ (28 octets) |
| |
| |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ TLVs ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: An example of an extended STAMP Session-Sender test packet
format in unauthenticated mode
An implementation of STAMP Session-Reflector that supports this
specification SHOULD identify a STAMP Session using the SSID in
combination with elements of the usual 4-tuple for the session.
Before a test session commences, a Session-Reflector MUST be
provisioned with all the elements that identify the STAMP Session. A
STAMP Session-Reflector MUST discard the non-matching STAMP test
packet(s). The means of provisioning the STAMP Session
identification is outside the scope of this specification. A
conforming implementation of STAMP Session-Reflector MUST copy the
SSID value from the received test packet and put it into the
reflected packet, as displayed in Figure 2.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Estimate | SSID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Receive Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Session-Sender Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Session-Sender Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Session-Sender Error Estimate | MBZ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Ses-Sender TTL | MBZ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ TLVs ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: An example of an extended STAMP Session-Reflector test
packet format in unauthenticated mode
A STAMP Session-Reflector that does not support this specification,
will return the zeroed SSID field in the reflected STAMP test packet.
The Session-Sender MAY stop the session if it receives a zeroed SSID
field. An implementation of a Session-Sender MUST support control of
its behavior in such a scenario. If the test session is not stopped,
the Session-Sender, can, for example, send a base STAMP packet
[RFC8762].
In the authenticated mode, location of SSID field is shown in
Figure 3 and Figure 4.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| MBZ (12 octets) |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Estimate | SSID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ ~
| MBZ (68 octets) |
~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| HMAC (16 octets) |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Base STAMP Session-Sender test packet format in
authenticated mode
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MBZ (12 octets) |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Error Estimate | SSID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MBZ (4 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Receive Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MBZ (8 octets) |
| |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Session-Sender Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| MBZ (12 octets) |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Session-Sender Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Session-Sender Error Estimate | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| MBZ (6 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Ses-Sender TTL | |
+-+-+-+-+-+-+-+-+ +
| |
| MBZ (15 octets) |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| HMAC (16 octets) |
| |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Base STAMP Session-Reflector test packet format in
authenticated mode
4. TLV Extensions to STAMP
Type-Length-Value (TLV) encoding scheme provides a flexible extension
mechanism for optional informational elements. TLV is an optional
field in the STAMP test packet. Multiple TLVs MAY be placed in the
STAMP test packet. A TLV MAY be enclosed in a TLV. TLVs have the
two octets long Type field, two octets long Length field that is
equal to the length of the Value field in octets. If a Type value
for TLV or sub-TLV is in the range for Vendor Private Use, the Length
MUST be at least 4, and the first four octets MUST be that vendor's
the Structure of Management Information (SMI) Private Enterprise
Codes, as recorded in IANA's SMI Private Enterprise Codes sub-
registry, in network octet order. The rest of the Value field is
private to the vendor. The following sections describe the use of
TLVs for STAMP that extends STAMP capability beyond its base
specification.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|STAMP TLV Flags| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Value ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: TLV Format in a STAMP Extended Packet
where fields are defined as the following:
o STAMP TLV Flags - eight-bit long field. Detailed format and
interpretation of flags defined in this specification is below.
o Type - one-octet long field that characterizes the interpretation
of the Value field. It is allocated by IANA, as specified in
Section 5.1
o Length - two-octets long field equals length on the Value field in
octets.
o Value - a variable-length field. Its interpretation and encoding
determined by the value of the Type field.
The format of the STAMP TLV Flags displayed in Figure 6 and the
location of flags is according to Section 5.2.
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|U|L|A|R|R|R|R|R|
+-+-+-+-+-+-+-+-+
Figure 6: STAMP TLV Flags Format
where fields are defined as the following:
o U - a one-bit flag. A Session-Sender MUST set the U flag to 0
before transmitting an extended STAMP test packet. A Session-
Reflector MUST set the U flag to 1 if the Session-Reflector has
not understood the TLV.
o L - a one-bit flag. A Session-Sender MUST set the L flag to 0
before transmitting an extended STAMP test packet. A Session-
Reflector MUST set the L flag to 1 if the Session-Reflector
determined the TLV is malformed, i.e., the Length field value of
the fixed-size TLV is not equal to the value defined for the
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particular type, or the remaining length of the extended STAMP
packet is less than the size of the TLV.
o A - a one-bit flag. A Session-Sender MUST set the A flag to 0
before transmitting an extended STAMP test packet. A Session-
Reflector MUST set the A flag to 1 if the STAMP extensions have
failed HMAC verification (Section 4.8).
o R - reserved flags for future use. These flags MUST be zeroed on
transmit and ignored on receipt.
A STAMP node, whether Session-Sender or Session-Reflector, receiving
a test packet MUST determine whether the packet is a base STAMP
packet or includes one or more TLVs. The node MUST compare the value
in the Length field of the UDP header and the length of the base
STAMP test packet in the mode, unauthenticated or authenticated based
on the configuration of the particular STAMP test session. If the
difference between the two values is larger than the length of UDP
header, then the test packet includes one or more STAMP TLVs that
immediately follow the base STAMP test packet. A Session-Reflector
that does not support STAMP extensions is not expected to compare the
value in the Length field of the UDP header and the length of the
STAMP base packet. Hence the Session-Reflector will transmit the
base STAMP packet. It is the local policy on the Session-Sender
(similar to the handling of SSID == 0 scenario described in
Section 3) that will control the sender's behavior.
A system that has received a STAMP test packet with extension TLVs
MUST validate each TLV:
If the U flag is set, the STAMP system MUST skip the processing of
the TLV. The implementation MUST try to process the next TLV if
present in the extended STAMP packet.
If the L flag is set, the STAMP system MUST stop processing the
remainder of the extended STAMP packet.
If the A flag is set, the STAMP system MUST discard all TLVs and
MUST stop processing the remainder of the extended STAMP packet.
If an implementation of a Session-Reflector does not recognize the
Type field value, it MUST include the copy of the TLV into the
reflected STAMP packet. The Session-Reflector MUST set the U flag
to 1. The Session-Reflector MUST try to process the next TLV in
the extended STAMP packet.
If a TLV is malformed, the processing of extension TLVs MUST be
stopped. The Session-Reflector MUST copy the remainder of the
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received extended STAMP packet into the reflected STAMP packet.
The Session-Reflector MUST set the L flag to 1.
Detected error events MUST be logged. Note that rate of logging MUST
be controlled.
4.1. Extra Padding TLV
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|STAMP TLV Flags|Extra Pad Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Extra Padding ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 7: Extra Padding TLV
where fields are defined as the following:
o STAMP TLV Flags - is eight-bit long field. Its format presented
in Figure 6.
o Extra Padding Type - is one octet long field, value TBA1 allocated
by IANA Section 5.1.
o Length - two octets long field equals length on the Extra Padding
field in octets.
o Extra Padding - a pseudo-random sequence of numbers. The field
MAY be filled with all zeros.
The Extra Padding TLV is similar to the Packet Padding field in
TWAMP-Test packet [RFC5357]. The use of the Extra Padding TLV is
RECOMMENDED to perform a STAMP test using test packets of larger size
than the base STAMP packet [RFC8762]. The length of the base STAMP
packet is 44 octets in the unauthenticated mode or 112 octets in the
authenticated mode. The Extra Padding TLV MAY be present more than
one time in an extended STAMP test packet.
4.2. Location TLV
STAMP Session-Sender MAY include the Location TLV to request
information from the Session-Reflector. The Session-Sender SHOULD
NOT fill any information fields except for Type and Length. The
Session-Reflector MUST validate the Length value against the address
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family of the transport encapsulating the STAMP test packet. If the
Length field's value is invalid, the Session-Reflector MUST zero all
fields and MUST NOT return any information to the Session-Sender.
The Session-Reflector MUST ignore all other fields of the received
Location TLV.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|STAMP TLV Flags| Location Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source MAC |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Destination IP Address ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Source IP Address ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Port | Source Port |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 8: Session-Reflector Location TLV
where fields are defined as the following:
o STAMP TLV Flags - is eight-bit long field. Its format presented
in Figure 6.
o Location Type - is one octet long field, value TBA2 allocated by
IANA Section 5.1.
o Length - two octets long field equals the length of the Value
field in octets. The Length field value MUST equal 20 octets for
the IPv4 address family. For the IPv6 address family, the value
of the Length field MUST equal 44 octets. All other values are
invalid.
o Source MAC - 6 octets 48 bits long field. The Session-Reflector
MUST copy Source MAC of received STAMP packet into this field.
o Reserved - two octets long field. MUST be zeroed on transmission
and ignored on reception.
o Destination IP Address - IPv4 or IPv6 destination address of the
packet received by the STAMP Session-Reflector.
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o Source IP Address - IPv4 or IPv6 source address of the packet
received by the STAMP Session-Reflector.
o Destination Port - two octets long UDP destination port number of
the received STAMP packet.
o Source Port - two octets long UDP source port number of the
received STAMP packet.
The Location TLV MAY be used to determine the last-hop IP addresses,
ports, and last-hop MAC address for STAMP packets. The MAC address
can indicate a path switch on the last hop The IP addresses and UDP
port will indicate if there is a NAT router on the path, and allows
the Session-Sender to identify the IP address of the Session-
Reflector behind the NAT, detect changes in the NAT mapping that
could cause sending the STAMP packets to the wrong Session-Reflector.
4.3. Timestamp Information TLV
STAMP Session-Sender MAY include the Timestamp Information TLV to
request information from the Session-Reflector. The Session-Sender
SHOULD NOT fill any information fields except for Type and Length.
The Session-Reflector MUST validate the Length value of the STAMP
test packet. If the value of the Length field is invalid, the
Session-Reflector MUST zero all fields and MUST NOT return any
information to the Session-Sender.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|STAMP TLV Flags|Times Info Type| Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sync. Src In | Timestamp In | Sync. Src Out | Timestamp Out |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 9: Timestamp Information TLV
where fields are defined as the following:
o STAMP TLV Flags - is eight-bit long field. Its format presented
in Figure 6.
o Timestamp Information Type - is one octet long field, value TBA3
allocated by IANA Section 5.1.
o Length - two octets long field, set equal to the value 4.
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o Sync Src In - one octet long field that characterizes the source
of clock synchronization at the ingress of Session-Reflector.
There are several methods to synchronize the clock, e.g., Network
Time Protocol (NTP) [RFC5905]. The value is one of those listed
in Table 5.
o Timestamp In - one octet long field that characterizes the method
by which the ingress of Session-Reflector obtained the timestamp
T2. A timestamp may be obtained with hardware assistance, via
software API from a local wall clock, or from a remote clock (the
latter is referred to as "control plane"). The value is one of
those listed in Table 7.
o Sync Src Out - one octet long field that characterizes the source
of clock synchronization at the egress of Session-Reflector. The
value is one of those listed in Table 5.
o Timestamp Out - one octet long field that characterizes the method
by which the egress of Session-Reflector obtained the timestamp
T3. The value is one of those listed in Table 7.
4.4. Class of Service TLV
The STAMP Session-Sender MAY include Class of Service (CoS) TLV in
the STAMP test packet. The format of the CoS TLV is presented in
Figure 10.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|STAMP TLV Flags| CoS Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DSCP1 | DSCP2 |ECN| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 10: Class of Service TLV
where fields are defined as the following:
o STAMP TLV Flags - is eight-bit long field. Its format presented
in Figure 6.
o CoS (Class of Service) Type - is one octet long field, value TBA4
allocated by IANA Section 5.1.
o Length - two octets long field, set equal to the value 4.
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o DSCP1 - The Differentiated Services Code Point (DSCP) intended by
the Session-Sender to be used as the DSCP value of the reflected
by the Session-Reflector test packet.
o DSCP2 - The received value in the DSCP field at the Session-
Reflector in the forward direction.
o ECN - The received value in the ECN field at the Session-Reflector
in the forward direction.
o Reserved - 18 bits long field, must be zeroed in transmission and
ignored on receipt.
A STAMP Session-Reflector that received the test packet with the CoS
TLV MUST include the CoS TLV in the reflected test packet. Also, the
Session-Reflector MUST copy the value of the DSCP and ECN fields of
the IP header of the received STAMP test packet into the DSCP2 field
in the reflected test packet. Finally, the Session-Reflector MUST
set the DSCP field's value in the IP header of the reflected test
packet equal to the value of the DSCP1 field of the received test
packet. Upon receiving the reflected packet, the Session-Sender will
save the DSCP and ECN values for analysis of the CoS in the reverse
direction.
Re-mapping of CoS can be used to provide multiple services (e,g., 2G,
3G, LTE in mobile backhaul networks) over the same network. But if
it is misconfigured, then it is often difficult to diagnose the root
cause of excessive packet drops of higher-level service while packet
drops for lower service packets are at a normal level. Using CoS TLV
in STAMP testing helps to troubleshoot the existing problem and also
verify whether DiffServ policies are processing CoS as required by
the configuration.
4.5. Direct Measurement TLV
The Direct Measurement TLV enables collection of "in profile" packets
that had been transmitted and received by the Session-Sender and
Session-Reflector respectfully. The definition of "in-profile
packet" is outside the scope of this document and is left to the test
operators to determine.
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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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|STAMP TLV Flags| Direct Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Session-Sender Tx counter (S_TxC) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Session-Reflector Rx counter (R_RxC) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Session-Reflector Tx counter (R_TxC) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 11: Direct Measurement TLV
where fields are defined as the following:
o STAMP TLV Flags - is eight-bit long field. Its format presented
in Figure 6.
o Direct (Measurement) Type - is one octet long field, value TBA5
allocated by IANA Section 5.1.
o Length - two octets long field equals length on the Value field in
octets. Length field value MUST equal 12 octets.
o Session-Sender Tx counter (S_TxC) is four octets long field. The
Session-Reflector MUST set its value equal to the number of the
transmitted in-profile packets.
o Session-Reflector Rx counter (R_RxC) is four octets long field.
MUST be zeroed by the Session-Sender on transmit and ignored by
the Session-Reflector on receipt. The Session-Reflector MUST fill
it with the value of in-profile packets received.
o Session-Reflector Tx counter (R_TxC) is four octets long field.
MUST be zeroed by the Session-Sender and ignored by the Session-
Reflector on receipt. The Session-Reflector MUST fill with the
value of the transmitted in-profile packets.
A Session-Sender MAY include the Direct Measurement TLV in a STAMP
test packet. The Session-Sender MUST zero R_RxC and R_TxC fields
before the transmission of the STAMP test packet. If the received
STAMP test packet includes the Direct Measurement TLV, the Session-
Reflector MUST include it in the reflected test packet. The Session-
Reflector MUST copy the value from the S_TxC field of the received
test packet into the same field of the reflected packet before its
transmission.
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4.6. Access Report TLV
A STAMP Session-Sender MAY include Access Report TLV (Figure 12) to
indicate changes to the access network status to the Session-
Reflector. The definition of an access network is outside the scope
of this document.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|STAMP TLV Flags|Acc Report Type| Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ID | Resv | Return Code | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 12: Access Report TLV
where fields are defined as follows:
o STAMP TLV Flags - is eight-bit long field. Its format presented
in Figure 6.
o Access Report Type - is one octet long field, value TBA6 allocated
by IANA Section 5.1.
o Length - two octets long field, set equal to the value 4.
o ID (Access ID) - four bits long field that identifies the access
network, e.g., 3GPP (Radio Access Technologies specified by 3GPP)
or Non-3GPP (accesses that are not specified by 3GPP) [TS23501].
The value is one of those listed below:
* 1 - 3GPP Network
* 2 - Non-3GPP Network
All other values are invalid and the TLV that contains it MUST be
discarded.
o Resv - four bits long field, MUST be zeroed on transmission and
ignored on receipt.
o Return Code - one octet long field that identifies the report
signal, e.g., available, unavailable. The value is passed,
supplied to the STAMP end-point through some mechanism that is
outside the scope of this document. The value is one of those
listed in Section 5.5.
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o Reserved - two octets long field, MUST be zeroed on transmission
and ignored on receipt.
The STAMP Session-Sender that includes the Access Report TLV sets the
value of the Access ID field according to the type of access network
it reports on. Also, the Session-Sender sets the value of the Return
Code field to reflect the operational state of the access network.
The mechanism to determine the state of the access network is outside
the scope of this specification. A STAMP Session-Reflector that
received the test packet with the Access Report TLV MUST include the
Access Report TLV in the reflected test packet. The Session-
Reflector MUST set the value of the Access ID and Return Code fields
equal to the values of the corresponding fields from the test packet
it has received.
The Session-Sender MUST also arm a retransmission timer after sending
a test packet that includes the Access Report TLV. This timer MUST
be disarmed upon the reception of the reflected STAMP test packet
that includes Access Report TLV. In the event the timer expires
before such a packet is received, the Session-Sender MUST retransmit
the STAMP test packet that contains the Access Report TLV. This
retransmission SHOULD be repeated up to four times before the
procedure is aborted. Setting the value for the retransmission timer
is based on local policies, network environment. The default value
of the retransmission timer for Access Report TLV SHOULD be three
seconds. An implementation MUST provide control of the
retransmission timer value and the number of retransmissions.
The Access Report TLV is used by the Performance Measurement Function
(PMF) components of the Access Steering, Switching and Splitting
feature for 5G networks [TS23501]. The PMF component in the User
Equipment acts as the STAMP Session-Sender, and the PMF component in
the User Plane Function acts as the STAMP Session-Reflector.
4.7. Follow-up Telemetry TLV
A Session-Reflector might be able to put in the Timestamp field only
an "SW Local" (see Table 7) timestamp. But the hosting system might
provide the timestamp closer to the start of the actual packet
transmission even though when it is not possible to deliver the
information to the Session-Sender in the packet itself. This
timestamp might nevertheless be important for the Session-Sender, as
it improves the accuracy of measuring network delay by minimizing the
impact of egress queuing delays on the measurement.
A STAMP Session-Sender MAY include the Follow-up Telemetry TLV to
request information from the Session-Reflector. The Session-Sender
MUST set the Follow-up Telemetry Type and Length fields to their
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appropriate values. Sequence Number and Timestamp fields MUST be
zeroed on transmission by the Session-Sender and ignored by the
Session-Reflector upon receipt of the STAMP test packet that includes
the Follow-up Telemetry TLV. The Session-Reflector MUST validate the
Length value of the STAMP test packet. If the value of the Length
field is invalid, the Session-Reflector MUST zero Sequence Number and
Timestamp fields. If the Session-Reflector is in stateless mode
(defined in Section 4.2 [RFC8762]), it MUST zero Sequence Number and
Timestamp fields.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|STAMP TLV Flags| Follow-up Type| Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Follow-up Timestamp |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Timestamp M | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 13: Follow-up Telemetry TLV
where fields are defined as follows:
o STAMP TLV Flags - is eight-bit long field. Its format presented
in Figure 6.
o Follow-up (Telemetry) Type - is one octet long field, value TBA7
allocated by IANA Section 5.1.
o Length - two octets long field, set equal to the value 16 octets.
o Sequence Number - four octets long field indicating the sequence
number of the last packet reflected in the same STAMP-test
session. Since the Session-Reflector runs in the stateful mode
(defined in Section 4.2 [RFC8762]), it is the Session-Reflector's
Sequence Number of the previous reflected packet.
o Follow-up Timestamp - eight octets long field, with the format
indicated by the Z flag of the Error Estimate field of the packet
transmitted by a Session-Reflector, as described in Section 4.1
[RFC8762]. It carries the timestamp when the reflected packet
with the specified sequence number was sent.
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o Timestamp M(ode) - one octet long field that characterizes the
method by which the entity that transmits a reflected STAMP packet
obtained the Follow-up Timestamp. The value is one of those
listed in Table 7.
o Reserved - the three octets-long field. Its value MUST be zeroed
on transmission and ignored on receipt.
4.8. HMAC TLV
The STAMP authenticated mode protects the integrity of data collected
in the STAMP base packet. STAMP extensions are designed to provide
valuable information about the condition of a network, and protecting
the integrity of that data is also essential. The keyed Hashed
Message Authentication Code (HMAC) TLV MUST be included in a STAMP
test packet in the authenticated mode, excluding when the only TLV
present is Extra Padding TLV. The HMAC TLV MUST follow all TLVs
included in a STAMP test packet, except for the Extra Padding TLV.
The HMAC TLV MAY be used to protect the integrity of STAMP extensions
in STAMP unauthenticated mode.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|STAMP TLV Flags| HMAC Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| HMAC |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 14: HMAC TLV
where fields are defined as follows:
o STAMP TLV Flags - is eight-bit long field. Its format presented
in Figure 6.
o HMAC Type - is one octet long field, value TBA8 allocated by IANA
Section 5.1.
o Length - two octets long field, set equal to the value 16 octets.
o HMAC - is 16 octets long field that carries HMAC digest of the
text of all preceding TLVs.
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As defined in [RFC8762], STAMP uses HMAC-SHA-256 truncated to 128
bits ([RFC4868]). All considerations regarding using the key and key
distribution and management listed in Section 4.4 of [RFC8762] are
fully applicable to the use of the HMAC TLV. HMAC is calculated as
defined in [RFC2104] over text as the concatenation of all preceding
TLVs. The digest then MUST be truncated to 128 bits and written into
the HMAC field. In the authenticated mode, HMAC MUST be verified
before using any data in the included STAMP TLVs. If HMAC
verification by the Session-Reflector fails, then the Session-
Reflector MUST stop processing the received extended STAMP test
packet. The Session-Reflector MUST copy the remainder of the
extended STAMP test packet into the reflected packet. The Session-
Reflector MUST set the A flag copy of the HMAC TLV in the reflected
packet to 1 before transmitting the reflected test packet. Also,
both Session-Sender and Session-Reflector SHOULD log the notification
that HMAC verification of STAMP TLVs failed.
5. IANA Considerations
5.1. STAMP TLV Registry
IANA is requested to create the STAMP TLV Type registry. All code
points in the range 1 through 32759 in this registry shall be
allocated according to the "IETF Review" procedure as specified in
[RFC8126]. Code points in the range 32760 through 65279 in this
registry shall be allocated according to the "First Come First
Served" procedure as specified in [RFC8126]. Remaining code points
are allocated according to Table 1:
+-----------+--------------+-------------------------+
| Value | Description | Reference |
+-----------+--------------+-------------------------+
| 0 | Reserved | This document |
| 1- 175 | Unassigned | IETF Review |
| 176 - 239 | Unassigned | First Come First Served |
| 240 - 251 | Experimental | This document |
| 252 - 254 | Private Use | This document |
| 255 | Reserved | This document |
+-----------+--------------+-------------------------+
Table 1: STAMP TLV Type Registry
This document defines the following new values in the STAMP Extension
TLV range of the STAMP TLV Type registry:
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+-------+-----------------------+---------------+
| Value | Description | Reference |
+-------+-----------------------+---------------+
| TBA1 | Extra Padding | This document |
| TBA2 | Location | This document |
| TBA3 | Timestamp Information | This document |
| TBA4 | Class of Service | This document |
| TBA5 | Direct Measurement | This document |
| TBA6 | Access Report | This document |
| TBA7 | Follow-up Telemetry | This document |
| TBA8 | HMAC | This document |
+-------+-----------------------+---------------+
Table 2: STAMP Types
5.2. STAMP TLV Flags Sub-registry
IANA is requested to create STAMP TLV Flags sub-registry as part of
the STAMP TLV Type registry. The registration procedure is "IETF
Review" [RFC8126]. Flags are 8 bits. This document defines the
following bit positions in the STAMP TLV Flags sub-registry:
+--------------+--------+-----------------------+---------------+
| Bit position | Symbol | Description | Reference |
+--------------+--------+-----------------------+---------------+
| 0 | U | Unrecognized TLV | This document |
| 1 | L | Malformed TLV | This document |
| 2 | A | Authentication failed | This document |
+--------------+--------+-----------------------+---------------+
Table 3: STAMP TLV Flags
5.3. Synchronization Source Sub-registry
IANA is requested to create Synchronization Source sub-registry as
part of the STAMP TLV Type registry. All code points in the range 1
through 127 in this registry shall be allocated according to the
"IETF Review" procedure as specified in [RFC8126]. Code points in
the range 128 through 239 in this registry shall be allocated
according to the "First Come First Served" procedure as specified in
[RFC8126]. Remaining code points are allocated according to Table 4:
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+-----------+--------------+-------------------------+
| Value | Description | Reference |
+-----------+--------------+-------------------------+
| 0 | Reserved | This document |
| 1- 127 | Unassigned | IETF Review |
| 128 - 239 | Unassigned | First Come First Served |
| 240 - 249 | Experimental | This document |
| 250 - 254 | Private Use | This document |
| 255 | Reserved | This document |
+-----------+--------------+-------------------------+
Table 4: Synchronization Source Sub-registry
This document defines the following new values in the Synchronization
Source sub-registry:
+-------+-------------------------+---------------+
| Value | Description | Reference |
+-------+-------------------------+---------------+
| 1 | NTP | This document |
| 2 | PTP | This document |
| 3 | SSU/BITS | This document |
| 4 | GPS/GLONASS/LORAN-C/BDS | This document |
| 5 | Local free-running | This document |
+-------+-------------------------+---------------+
Table 5: Synchronization Sources
5.4. Timestamping Method Sub-registry
IANA is requested to create Timestamping Method sub-registry as part
of the STAMP TLV Type registry. All code points in the range 1
through 127 in this registry shall be allocated according to the
"IETF Review" procedure as specified in [RFC8126]. Code points in
the range 128 through 239 in this registry shall be allocated
according to the "First Come First Served" procedure as specified in
[RFC8126]. Remaining code points are allocated according to Table 6:
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+-----------+--------------+-------------------------+
| Value | Description | Reference |
+-----------+--------------+-------------------------+
| 0 | Reserved | This document |
| 1- 127 | Unassigned | IETF Review |
| 128 - 239 | Unassigned | First Come First Served |
| 240 - 249 | Experimental | This document |
| 250 - 254 | Private Use | This document |
| 255 | Reserved | This document |
+-----------+--------------+-------------------------+
Table 6: Timestamping Method Sub-registry
This document defines the following new values in the Timestamping
Methods sub-registry:
+-------+---------------+---------------+
| Value | Description | Reference |
+-------+---------------+---------------+
| 1 | HW Assist | This document |
| 2 | SW local | This document |
| 3 | Control plane | This document |
+-------+---------------+---------------+
Table 7: Timestamping Methods
5.5. Return Code Sub-registry
IANA is requested to create Return Code sub-registry as part of STAMP
TLV Type registry. All code points in the range 1 through 127 in
this registry shall be allocated according to the "IETF Review"
procedure as specified in [RFC8126]. Code points in the range 128
through 239 in this registry shall be allocated according to the
"First Come First Served" procedure as specified in [RFC8126].
Remaining code points are allocated according to Table 8:
+-----------+--------------+-------------------------+
| Value | Description | Reference |
+-----------+--------------+-------------------------+
| 0 | Reserved | This document |
| 1- 127 | Unassigned | IETF Review |
| 128 - 239 | Unassigned | First Come First Served |
| 240 - 249 | Experimental | This document |
| 250 - 254 | Private Use | This document |
| 255 | Reserved | This document |
+-----------+--------------+-------------------------+
Table 8: Return Code Sub-registry
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This document defines the following new values in the Return Code
sub-registry:
+-------+---------------------+---------------+
| Value | Description | Reference |
+-------+---------------------+---------------+
| 1 | Network available | This document |
| 2 | Network unavailable | This document |
+-------+---------------------+---------------+
Table 9: Return Codes
6. Security Considerations
This document defines extensions to STAMP [RFC8762] and inherits all
the security considerations applicable to the base protocol.
Additionally, the HMAC TLV is defined in this document to protect the
integrity of optional STAMP extensions. The use of HMAC TLV is
discussed in detail in Section 4.8.
7. Acknowledgments
Authors much appreciate the thorough review and thoughtful comments
received from Tianran Zhou, Rakesh Gandhi, Yuezhong Song and Yali
Wang. The authors express their gratitude to Al Morton for his
comments and the most valuable suggestions. The authors greatly
appreciate comments and thoughtful suggestions received from Martin
Duke.
8. Contributors
The following people contributed text to this document:
Guo Jun
ZTE Corporation
68# Zijinghua Road
Nanjing, Jiangsu 210012
P.R.China
Phone: +86 18105183663
Email: guo.jun2@xxxxxxxxxx
9. References
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9.1. 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>.
[RFC5357] Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and J.
Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)",
RFC 5357, DOI 10.17487/RFC5357, October 2008,
<https://www.rfc-editor.org/info/rfc5357>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8762] Mirsky, G., Jun, G., Nydell, H., and R. Foote, "Simple
Two-Way Active Measurement Protocol", RFC 8762,
DOI 10.17487/RFC8762, March 2020,
<https://www.rfc-editor.org/info/rfc8762>.
[TS23501] 3GPP (3rd Generation Partnership Project), "Technical
Specification Group Services and System Aspects; System
Architecture for the 5G System; Stage 2 (Release 16)",
3GPP TS23501, 2019.
9.2. Informative References
[GPS] "Global Positioning System (GPS) Standard Positioning
Service (SPS) Performance Standard", GPS SPS 5th Edition,
April 2020.
[IEEE.1588.2008]
"Standard for a Precision Clock Synchronization Protocol
for Networked Measurement and Control Systems",
IEEE Standard 1588, March 2008.
[RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed-
Hashing for Message Authentication", RFC 2104,
DOI 10.17487/RFC2104, February 1997,
<https://www.rfc-editor.org/info/rfc2104>.
Mirsky, et al. Expires January 3, 2021 [Page 26]
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[RFC4868] Kelly, S. and S. Frankel, "Using HMAC-SHA-256, HMAC-SHA-
384, and HMAC-SHA-512 with IPsec", RFC 4868,
DOI 10.17487/RFC4868, May 2007,
<https://www.rfc-editor.org/info/rfc4868>.
[RFC5905] Mills, D., Martin, J., Ed., Burbank, J., and W. Kasch,
"Network Time Protocol Version 4: Protocol and Algorithms
Specification", RFC 5905, DOI 10.17487/RFC5905, June 2010,
<https://www.rfc-editor.org/info/rfc5905>.
Authors' Addresses
Greg Mirsky
ZTE Corp.
Email: gregimirsky@xxxxxxxxx
Xiao Min
ZTE Corp.
Email: xiao.min2@xxxxxxxxxx
Henrik Nydell
Accedian Networks
Email: hnydell@xxxxxxxxxxxx
Richard Foote
Nokia
Email: footer.foote@xxxxxxxxx
Adi Masputra
Apple Inc.
One Apple Park Way
Cupertino, CA 95014
USA
Email: adi@xxxxxxxxx
Mirsky, et al. Expires January 3, 2021 [Page 27]
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Ernesto Ruffini
OutSys
via Caracciolo, 65
Milano 20155
Italy
Email: eruffini@xxxxxxxxxx
Mirsky, et al. Expires January 3, 2021 [Page 28]
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