Performance Measurement with Asymmetrical Packets in STAMP

Simple Two-way Active Measurement Protocol (STAMP) defined the STAMP base functionalities and, among them, the use of symmetrical test packets. In some scenarios, e.g., rate measurements discussed in , it is beneficial not only to use a variable size of the test packets transmitted downstream while controlling length, number, and interpacket interval for reflected test packets. This document specifies an optional extension of STAMP as defined in that allows for control of the length, number, and interpacket interval of a reflected STAMP test packets transmitted in response to a received STAMP test packet.

Terminology STAMP Simple Two-way Active Measurement Protocol

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 14 and when, and only when, they appear in all capitals, as shown here.

Problem Statement STAMP () allows for variable lengths of the test packets transmitted by a Session-Sender. analyses rate measurement scenarios where it is beneficial to enable control of the responding node reflecting the received test packet with a different length and, in some cases, with a series of equally timed test packets.

Reflected Test Packet Control TLV This document defines a new optional STAMP extension, Reflected Test Packet Control TLV. The format of the Reflected Test Packet Control TLV is presented in .

Reflected Test Packet Control TLV Format The interpretation of the fields is as follows:

STAMP TLV Flags is a one-octet field.
Type is a fourteen-bit field that identifies the Reflected Test Packet Control TLV. IANA is requested () to assign (TBD1) value.
Length is a two-octet field. The value is variable, not smaller than 12 octets.
Length of the Reflected Packet is a four-octet field. The value is an unsigned integer that is the requested length of a reflected test packet in octets.
Number of the Reflected Packets is a four-octet field. The value is the number of reflected test packets the Session-Reflector is requested to transmit in response to receiving a STAMP test packet with the Reflected Test Packet Control TLV.
Interval Between Reflected Packets is a four-octet field. The value is an unsigned integer set to the interval in milliseconds between the transmission of the consecutive reflected test packets in response to receiving a STAMP test packet with the Reflected Test Packet Control TLV.
Sub-TLVs - optional field that includes additional information communicated by a Session-Sender.

A Session-Sender MAY include the Reflected Test Packet Control TLV in a STAMP test packet. If the received STAMP test packet includes the Reflected Test Packet Control TLV, the Session-Reflector MUST transmit a sequence of reflected test packets according to the following rules:

The length of the reflected test packet MUST be the largest of the length of the Session-Reflector packet in the mode matching mode of the received STAMP test packet, as defined in Section 4.3 of with all the present in the received STAMP test packet STAMP extension TLVs , excluding the Extra Padding TLV, and the value in the Length of the Reflected Packet aligned at a four-octets boundary. The Session-Reflector MUST use the Extra Padding TLV (Section 4.1 of ) to increase the length of the reflected test packet.
The number of reflected test packets in the sequence MUST equal to the value of the Number of the Reflected Test Packets.
If the value of the Number of Reflected Packets is larger than one, the interval between the transmission of two consecutive reflected packets in the sequence MUST be equal to the value in the Interval Between Reflected Packets in milliseconds.
If the value of the Number of Reflected Packets equals zero, then the Session-Reflector MUST NOT send a reflected packet. Processing of the received STAMP test packet with the Reflected Test Packet Control TLV is according to the local policy.
Each reflected test packet in the sequence is formed according to Section 4.3 of .

Theory of Operation TBA

IANA Considerations The IANA is requested to assign a new value for the Reflected Test Packet Control TLV from the STAMP TLV Types subregistry according to . New Reflected Test Packet Control Type TLV

Value	Description	Reference
(TBD1)	Reflected Test Packet Control TLV	This document

Security Considerations Security considerations discussed in and apply to this document. Furthermore, spoofed STAMP test packets with the Reflected Test Packet Control TLV can be exploited to conduct Denial-of-Service attack. Hence, implementations MUST provide a means of checking the source addresses of the STAMP test packets containing the Reflected Test Packet Control TLV.

Acknowledgments TBA