| Network Working Group | G. Mirsky |
| Internet-Draft | ZTE Corp. |
| Intended status: Standards Track | G. Jun |
| Expires: June 1, 2019 | ZTE Corporation |
| H. Nydell | |
| Accedian Networks | |
| R. Foote | |
| Nokia | |
| November 28, 2018 |
Simple Two-way Active Measurement Protocol
draft-ietf-ippm-stamp-05
This document describes a Simple Two-way Active Measurement Protocol which enables the measurement of both one-way and round-trip performance metrics like delay, delay variation, and packet loss.
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Development and deployment of Two-Way Active Measurement Protocol (TWAMP) [RFC5357] and its extensions, e.g., [RFC6038] that defined features such as Reflect Octets and Symmetrical Size for TWAMP provided invaluable experience. Several independent implementations exist, have been deployed and provide important operational performance measurements. At the same time, there has been noticeable interest in using a simpler mechanism for active performance monitoring that can provide deterministic behavior and inherit separation of control (vendor-specific configuration or orchestration) and test functions. One of such is Performance Measurement from IP Edge to Customer Equipment using TWAMP Light from Broadband Forum ([BBF.TR-390]). This document defines active performance measurement test protocol, Simple Two-way Active Measurement Protocol (STAMP), that enables measurement of both one-way and round-trip performance metrics like delay, delay variation, and packet loss.
AES Advanced Encryption Standard
CBC Cipher Block Chaining
ECB Electronic Cookbook
KEK Key-encryption Key
STAMP - Simple Two-way Active Measurement Protocol
NTP - Network Time Protocol
PTP - Precision Time Protocol
HMAC Hashed Message Authentication Code
OWAMP One-Way Active Measurement Protocol
TWAMP Two-Way Active Measurement Protocol
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 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.
Figure 1 presents Simple Two-way Active Measurement Protocol (STAMP) Session-Sender and Session-Reflector with a measurement session. The configuration and management of the STAMP Session-Sender, Session-Reflector and management of the STAMP sessions can be achieved through various means. Command Line Interface, OSS/BSS using SNMP or SDN using Netconf/YANG are but a few examples.
o----------------------------------------------------------o
| Configuration and |
| Management |
o----------------------------------------------------------o
|| ||
|| ||
|| ||
+----------------------+ +-------------------------+
| STAMP Session-Sender | <--- STAMP---> | STAMP Session-Reflector |
+----------------------+ +-------------------------+
Figure 1: STAMP Reference Model
STAMP Session-Sender transmits test packets toward 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., size of the packet transmitted by Session-Reflector equals the size of the packet received by the Session-Reflector.
Because STAMP supports symmetrical test packets, STAMP Session-Sender packet has a minimum size of 44 octets in unauthenticated mode, see Figure 2, and 48 octets in the authenticated mode, see Figure 4.
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 | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| |
| |
| MBZ (27 octets) |
| |
| |
| |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | Server Octets | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| Remaining Packet Padding (to be reflected) |
~ (length in octets specified in Server Octets) ~
+ +-+-+-+-+-+-+-+-+
| | Comp.MBZ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ Value ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: STAMP Session-Sender test packet format in unauthenticated mode
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|S|Z| Scale | Multiplier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Error Estimate Format
For unauthenticated mode:
The STAMP Session-Sender and Session-Reflector MAY use, not use, or set value of the Z field in accordance with the timestamp format in use. This optional field is to enhance operations, but local configuration or defaults could be used in its place.
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 | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + ~ ~ | MBZ (70 octets) | ~ ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Value ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Comp.MBZ ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | | HMAC (16 octets) | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: STAMP Session-Sender test packet format in authenticated mode
For authenticated mode:
The field definitions are the same as the unauthenticated mode, listed in Section 4.1.1. Also, Comp.MBZ field is variable length field to align the packet on 16 octets boundary. Also, the packet includes a key-hashed message authentication code (HMAC) ([RFC2104]) hash at the end of the PDU.
The Session-Reflector receives the STAMP test packet, verifies it, prepares and transmits the reflected test packet.
Two modes of STAMP Session-Reflector characterize the expected behavior and, consequently, performance metrics that can be measured:
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 | MBZ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Receive Timestamp | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Session-Sender Sequence Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Session-Sender Timestamp | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Session-Sender Error Estimate | MBZ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Ses-Sender TTL | | +-+-+-+-+-+-+-+-+ + | | ~ Packet Padding (reflected) ~ + +-+-+-+-+-+-+-+-+ | | Comp.MBZ | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Value ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: STAMP Session-Reflector test packet format in unauthenticated mode
For 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MBZ (12 octets) | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Timestamp | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Error Estimate | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | MBZ (6 octets) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Receive Timestamp | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MBZ (8 octets) | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Session-Sender Sequence Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MBZ (12 octets) | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Session-Sender Timestamp | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Session-Sender Error Estimate | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | MBZ (6 octets) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Ses-Sender TTL | | +-+-+-+-+-+-+-+-+ + | | | MBZ (15 octets) | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Value ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Comp.MBZ ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | HMAC (16 octets) | | | | | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: STAMP Session-Reflector test packet format in authenticated mode
For the authenticated mode:
The field definitions are the same as the unauthenticated mode, listed in Section 4.2.1. Additionally, the packet MAY include Comp.MBZ field is variable length field to align the packet on 16 octets boundary. Also, STAMP Session-Reflector test packet format in authenticated mode includes a key (HMAC) ([RFC2104]) hash at the end of the PDU.
To provide integrity protection, each STAMP message is being authenticated by adding Hashed Message Authentication Code (HMAC). STAMP uses HMAC-SHA-256 truncated to 128 bits (similarly to the use of it in IPSec defined in [RFC4868]); hence the length of the HMAC field is 16 octets. HMAC uses own key and the definition of the mechanism to distribute the HMAC key is outside the scope of this specification. One example is to use an orchestrator to configure HMAC key based on STAMP YANG data model [I-D.ietf-ippm-stamp-yang]. HMAC MUST be verified as early as possible to avoid using or propagating corrupted data.
If confidentiality protection for STAMP is required, encryption at the higher level MUST be used.
One of the essential requirements to STAMP is the ability to interwork with TWAMP Light device. There are two possible combinations for such use case:
In the former case, Session-Sender MAY not be aware that its Session-Reflector does not support STAMP. For example, TWAMP Light Session-Reflector may not support the use of UDP port 862 as defined in [I-D.ietf-ippm-port-twamp-test]. Thus STAMP Session-Sender MUST be able to send test packets to destination UDP port number from the Dynamic and/or Private Ports range 49152-65535, test management system should find port number that both devices can use. And if any of TLV-based STAMP extensions are used, the TWAMP Light Session-Reflector will view them as Packet Padding field. The Session-Sender SHOULD use the default format for its timestamps - NTP. And it MAY use PTPv2 timestamp format.
In the latter scenario, the test management system should set STAMP Session-Reflector to use UDP port number from the Dynamic and/or Private Ports range. As for Packet Padding field that the TWAMP Light Session-Sender includes in its transmitted packet, the STAMP Session-Reflector will process it according to [RFC6038] and return reflected packet of the symmetrical size. The Session-Reflector MUST use the default format for its timestamps - NTP.
This document doesn't have any IANA action. This section may be removed before the publication.
Use of HMAC-SHA-256 in the authenticated mode protects the data integrity of the STAMP test packets.
Authors express their appreciation to Jose Ignacio Alvarez-Hamelin and Brian Weis for their great insights into the security and identity protection, and the most helpful and practical suggestions.
| [I-D.ietf-ippm-stamp-yang] | Mirsky, G., Xiao, M. and W. Luo, "Simple Two-way Active Measurement Protocol (STAMP) Data Model", Internet-Draft draft-ietf-ippm-stamp-yang-02, September 2018. |
| [RFC2104] | Krawczyk, H., Bellare, M. and R. Canetti, "HMAC: Keyed-Hashing for Message Authentication", RFC 2104, DOI 10.17487/RFC2104, February 1997. |
| [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. |