rfc9571v2.txt		rfc9571.txt
	skipping to change at line 73 ¶		skipping to change at line 73 ¶
	4. RFC 6374-Based Single Packet Delay Measurement Using SFL		4. RFC 6374-Based Single Packet Delay Measurement Using SFL
	5. Data Service Packet Delay Measurement		5. Data Service Packet Delay Measurement
	6. Some Simplifying Rules		6. Some Simplifying Rules
	7. Multiple Packet Delay Characteristics		7. Multiple Packet Delay Characteristics
	7.1. Method 1: Time Buckets		7.1. Method 1: Time Buckets
	7.2. Method 2: Classic Standard Deviation		7.2. Method 2: Classic Standard Deviation
	7.2.1. Multi-packet Delay Measurement Message Format		7.2.1. Multi-packet Delay Measurement Message Format
	7.3. Per-Packet Delay Measurement		7.3. Per-Packet Delay Measurement
	7.4. Average Delay		7.4. Average Delay
	8. Sampled Measurement		8. Sampled Measurement
	9. Carrying RFC 6374 Packets over an LSP Using an SFL		9. Carrying Packets over an LSP Using an SFL
	9.1. Extending RFC 6374 with SFL TLV		9.1. Extending RFC 6374 with SFL TLV
	10. RFC 6374-Based Combined Loss/Delay Measurement Using SFL		10. RFC 6374-Based Combined Loss/Delay Measurement Using SFL
	11. Privacy Considerations		11. Privacy Considerations
	12. Security Considerations		12. Security Considerations
	13. IANA Considerations		13. IANA Considerations
	13.1. Allocation of MPLS Generalized Associated Channel (G-ACh)		13.1. Allocation of MPLS Generalized Associated Channel (G-ACh)
	Types		Types
	13.2. Allocation of MPLS Loss/Delay TLV Object		13.2. Allocation of MPLS Loss/Delay TLV Object
	14. References		14. References
	14.1. Normative References		14.1. Normative References
	skipping to change at line 148 ¶		skipping to change at line 148 ¶
	some source-specific information into the packet to identify packet		some source-specific information into the packet to identify packet
	batches from a specific source.		batches from a specific source.
	[RFC8957] describes a method of encoding per-flow instructions in an		[RFC8957] describes a method of encoding per-flow instructions in an
	MPLS label stack using a technique called Synonymous Flow Labels		MPLS label stack using a technique called Synonymous Flow Labels
	(SFLs), in which labels that mimic the behavior of other labels		(SFLs), in which labels that mimic the behavior of other labels
	provide the packet batch identifiers and enable the per-batch packet		provide the packet batch identifiers and enable the per-batch packet
	accounting. This memo specifies how SFLs are used to perform packet		accounting. This memo specifies how SFLs are used to perform packet
	loss and delay measurements as described in [RFC6374].		loss and delay measurements as described in [RFC6374].
	When the terms "Query," "packet," or "message" are used in this		When the terms "performance measurement method," "Query," "packet,"
	document, they refer to a Query, packet, or message as specified in		or "message" are used in this document, they refer to a performance
			measurement method, Query, packet, or message as specified in
	[RFC6374].		[RFC6374].
	2. Requirements Language		2. Requirements Language
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and		"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
	"OPTIONAL" in this document are to be interpreted as described in		"OPTIONAL" in this document are to be interpreted as described in
	BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all		BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
	capitals, as shown here.		capitals, as shown here.
	3. RFC 6374-Based Packet Loss Measurement Using SFL		3. RFC 6374-Based Packet Loss Measurement Using SFL
	The data service packets of the flow being instrumented are grouped		The data service packets of the flow being instrumented are grouped
	into batches, and all the packets within a batch are marked with the		into batches, and all the packets within a batch are marked with the
	SFL [RFC8372] corresponding to that batch. The sender counts the		SFL [RFC8372] corresponding to that batch. The sender counts the
	number of packets in the batch. When the batch has completed and the		number of packets in the batch. When the batch has completed and the
	sender is confident that all of the packets in that batch will have		sender is confident that all of the packets in that batch will have
	been received, the sender issues an [RFC6374] Query message to		been received, the sender issues a Query message to determine the
	determine the number actually received and hence the number of		number actually received and hence the number of packets lost. The
	packets lost. The [RFC6374] Query message is sent using the same SFL		Query message is sent using the same SFL as the corresponding batch
	as the corresponding batch of data service packets. The format of		of data service packets. The format of the Query and Response
	the Query and Response packets is described in Section 9.		packets is described in Section 9.
	4. RFC 6374-Based Single Packet Delay Measurement Using SFL		4. RFC 6374-Based Single Packet Delay Measurement Using SFL
	[RFC6374] describes how to measure the packet delay by measuring the		[RFC6374] describes how to measure the packet delay by measuring the
	transit time of an [RFC6374] packet over an LSP. Such a packet may		transit time of a packet over an LSP. Such a packet may not need to
	not need to be carried over an SFL since the delay over a particular		be carried over an SFL since the delay over a particular LSP should
	LSP should be a function of the Traffic Class (TC) bits.		be a function of the Traffic Class (TC) bits.
	However, where SFLs are being used to monitor packet loss or where		However, where SFLs are being used to monitor packet loss or where
	label-inferred scheduling is used [RFC3270], then the SFL would be		label-inferred scheduling is used [RFC3270], then the SFL would be
	REQUIRED to ensure that the [RFC6374] packet that was being used as a		REQUIRED to ensure that the packet that was being used as a proxy for
	proxy for a data service packet experienced a representative delay.		a data service packet experienced a representative delay. The format
	The format of an [RFC6374] packet carried over the LSP using an SFL		of a packet carried over the LSP using an SFL is shown in Section 9.
	is shown in Section 9.
	5. Data Service Packet Delay Measurement		5. Data Service Packet Delay Measurement
	Where it is desired to more thoroughly instrument a packet flow and		Where it is desired to more thoroughly instrument a packet flow and
	to determine the delay of a number of packets, it is undesirable to		to determine the delay of a number of packets, it is undesirable to
	send a large number of [RFC6374] packets acting as proxy data service		send a large number of packets acting as proxy data service packets
	packets (see Section 4). A method of directly measuring the delay		(see Section 4). A method of directly measuring the delay
	characteristics of a batch of packets is therefore needed.		characteristics of a batch of packets is therefore needed.
	Given the long intervals over which it is necessary to measure packet		Given the long intervals over which it is necessary to measure packet
	loss, it is not necessarily the case that the batch times for the two		loss, it is not necessarily the case that the batch times for the two
	measurement types would be identical. Thus, we use a technique that		measurement types would be identical. Thus, we use a technique that
	permits the two measurements to be made concurrently and yet		permits the two measurements to be made concurrently and yet
	relatively independently from each other. The notion that they are		relatively independently from each other. The notion that they are
	relatively independent arises from the potential for the two batches		relatively independent arises from the potential for the two batches
	to overlap in time, in which case either the delay batch time will		to overlap in time, in which case either the delay batch time will
	need to be cut short or the loss time will need to be extended to		need to be cut short or the loss time will need to be extended to
	skipping to change at line 229 ¶		skipping to change at line 229 ¶
	(Case 4) AACDCDCDAABBBBBBBBBBAAAAAAAAAABBBBBBBBBB		(Case 4) AACDCDCDAABBBBBBBBBBAAAAAAAAAABBBBBBBBBB
	A case of multiple delay measurements within a packet loss		A case of multiple delay measurements within a packet loss
	measurement		measurement
	where		where
	A and B are packets where loss is being measured.		A and B are packets where loss is being measured.
	C and D are packets where loss and delay are being measured.		C and D are packets where loss and delay are being measured.
	Figure 1: RFC 6734 Query Packet with SFL		Figure 1: Query Packet with SFL
	In Case 1, we show where loss measurement alone is being carried out		In Case 1, we show where loss measurement alone is being carried out
	on the flow under analysis. For illustrative purposes, consider that		on the flow under analysis. For illustrative purposes, consider that
	10 packets are used in each flow in the time interval being analyzed.		10 packets are used in each flow in the time interval being analyzed.
	Now consider Case 2, where a small batch of packets need to be		Now consider Case 2, where a small batch of packets need to be
	analyzed for delay. These are marked with a different SFL type,		analyzed for delay. These are marked with a different SFL type,
	indicating that they are to be monitored for both loss and delay.		indicating that they are to be monitored for both loss and delay.
	The SFL=A indicates loss batch A, and SFL=D indicates a batch of		The SFL=A indicates loss batch A, and SFL=D indicates a batch of
	packets that are to be instrumented for delay, but SFL D is		packets that are to be instrumented for delay, but SFL D is
	synonymous with SFL A, which in turn is synonymous with the		synonymous with SFL A, which in turn is synonymous with the
	underlying Forwarding Equivalence Class (FEC). Thus, a packet marked		underlying Forwarding Equivalence Class (FEC). Thus, a packet marked
	"D" will be accumulated into the A loss batch, into the delay		"D" will be accumulated into the A loss batch, into the delay
	statistics, and will be forwarded as normal. Whether the packet is		statistics, and will be forwarded as normal. Whether the packet is
	actually counted twice (for loss and delay) or whether the two		actually counted twice (for loss and delay) or whether the two
	counters are reconciled during reporting is a local matter.		counters are reconciled during reporting is a local matter.
	Now consider Case 3, where a small batch of packets is marked for		Now consider Case 3, where a small batch of packets is marked for
	delay across a loss batch boundary. These packets need to be		delay across a loss batch boundary. These packets need to be
	considered as a part of batch A or a part of batch B, and any		considered as a part of batch A or a part of batch B, and any Query
	[RFC6374] Query needs to take place after all packets A or D		needs to take place after all packets A or D (whichever option is
	(whichever option is chosen) have arrived at the receiving Label		chosen) have arrived at the receiving Label Switching Router (LSR).
	Switching Router (LSR).
	Now consider Case 4. Here, we have a case where it is required to		Now consider Case 4. Here, we have a case where it is required to
	take a number of delay measurements within a batch of packets that we		take a number of delay measurements within a batch of packets that we
	are measuring for loss. To do this, we need two SFLs for delay (C		are measuring for loss. To do this, we need two SFLs for delay (C
	and D) and alternate between them (on a delay-batch-by-delay-batch		and D) and alternate between them (on a delay-batch-by-delay-batch
	basis) for the purposes of measuring the delay characteristics of the		basis) for the purposes of measuring the delay characteristics of the
	different batches of packets.		different batches of packets.
	6. Some Simplifying Rules		6. Some Simplifying Rules
	skipping to change at line 349 ¶		skipping to change at line 348 ¶
	| QTF | RTF | RPTF | Reserved |		| QTF | RTF | RPTF | Reserved |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Session Identifier | DS |		| Session Identifier | DS |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Number of | Reserved 1 |		| Number of | Reserved 1 |
	| Buckets | |		| Buckets | |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Interval (in 10 ns units) |		| Interval (in 10 ns units) |
	| |		| |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Number of Pkts in Bucket |		| Number of Pkts in Bucket 1 |
	| |		| |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	~ ~		~ ~
	~ ~		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
			| Number of Pkts in Bucket N |
			| |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	~ ~		~ ~
	~ TLV Block ~		~ TLV Block ~
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Figure 2: Time Bucket Jitter Measurement Message Format		Figure 2: Time Bucket Jitter Measurement Message Format
	The Version, Flags, Control Code, Message Length, Querier Timestamp		The Version, Flags, Control Code, Message Length, Querier Timestamp
	Format (QTF), Responder Timestamp Format (RTF), Responder's Preferred		Format (QTF), Responder Timestamp Format (RTF), Responder's Preferred
	Timestamp Format (RPTF), Session Identifier, Reserved, and		Timestamp Format (RPTF), Session Identifier, Reserved, and
	skipping to change at line 375 ¶		skipping to change at line 376 ¶
	[RFC6374]. The remaining fields, which are unsigned integers, are as		[RFC6374]. The remaining fields, which are unsigned integers, are as
	follows:		follows:
	* Number of Buckets in the measurement.		* Number of Buckets in the measurement.
	* Reserved 1 must be sent as zero and ignored on receipt.		* Reserved 1 must be sent as zero and ignored on receipt.
	* Interval (in 10 ns units) is the inter-packet interval for this		* Interval (in 10 ns units) is the inter-packet interval for this
	bucket.		bucket.
	* Number of Pkts in Bucket is the number of packets found in this		* Number of Pkts in Bucket 1 is the number of packets found in the
	bucket.		first bucket.
			* Number of Pkts in Bucket N is the number of packets found in the
			Nth bucket, where N is the value in the Number of Buckets field.
	There will be a number of Interval/Number pairs depending on the		There will be a number of Interval/Number pairs depending on the
	number of buckets being specified by the Querier. If an [RFC6374]		number of buckets being specified by the Querier. If a message is
	message is being used to configure the buckets (i.e., the responder		being used to configure the buckets (i.e., the responder is creating
	is creating or modifying the buckets according to the intervals in		or modifying the buckets according to the intervals in the Query
	the Query message), then the responder MUST respond with 0 packets in		message), then the responder MUST respond with 0 packets in each
	each bucket until it has been configured for a full measurement		bucket until it has been configured for a full measurement period.
	period. This indicates that it was configured at the time of the		This indicates that it was configured at the time of the last
	last response message, and thus, the response is valid for the whole		response message, and thus, the response is valid for the whole
	interval. As per the convention in [RFC6374], the Number of Pkts in		interval. As per the convention in [RFC6374], the Number of Pkts in
	Bucket fields are included in the Query message and set to zero.		Bucket fields are included in the Query message and set to zero.
	Out-of-band configuration is permitted by this mode of operation.		Out-of-band configuration is permitted by this mode of operation.
	Note this is a departure from the normal fixed format used in		Note this is a departure from the normal fixed format used in
	[RFC6374].		[RFC6374].
	The Time Bucket Jitter Measurement message is carried over an LSP in		The Time Bucket Jitter Measurement message is carried over an LSP in
	the way described in [RFC6374] and over an LSP with an SFL as		the way described in [RFC6374] and over an LSP with an SFL as
	skipping to change at line 571 ¶		skipping to change at line 575 ¶
	8. Sampled Measurement		8. Sampled Measurement
	In the discussion so far, it has been assumed that we would measure		In the discussion so far, it has been assumed that we would measure
	the delay characteristics of every packet in a delay measurement		the delay characteristics of every packet in a delay measurement
	interval defined by an SFL of constant color. In [RFC9341], the		interval defined by an SFL of constant color. In [RFC9341], the
	concept of a sampled measurement is considered. That is, the		concept of a sampled measurement is considered. That is, the
	responder only measures a packet at the start of a group of packets		responder only measures a packet at the start of a group of packets
	being marked for delay measurement by a particular color, rather than		being marked for delay measurement by a particular color, rather than
	every packet in the marked batch. A measurement interval is not		every packet in the marked batch. A measurement interval is not
	defined by the duration of a marked batch of packets but the interval		defined by the duration of a marked batch of packets but the interval
	between a pair of [RFC6374] packets taking a readout of the delay		between a pair of packets taking a readout of the delay
	characteristic. This approach has the advantage that the measurement		characteristic. This approach has the advantage that the measurement
	is not impacted by ECMP effects.		is not impacted by ECMP effects.
	This sampled approach may be used if supported by the responder and		This sampled approach may be used if supported by the responder and
	configured by the operator.		configured by the operator.
	9. Carrying RFC 6374 Packets over an LSP Using an SFL		9. Carrying Packets over an LSP Using an SFL
	We illustrate the packet format of an [RFC6374] Query message using		We illustrate the packet format of a Query message using SFLs for the
	SFLs for the case of an MPLS Direct Loss Measurement in Figure 5.		case of an MPLS Direct Loss Measurement in Figure 5.
	+-------------------------------+		+-------------------------------+
	| |		| |
	| LSP |		| LSP |
	| Label |		| Label |
	+-------------------------------+		+-------------------------------+
	| |		| |
	| Synonymous Flow |		| Synonymous Flow |
	| Label |		| Label |
	+-------------------------------+		+-------------------------------+
	| |		| |
	| GAL |		| GAL |
	| |		| |
	+-------------------------------+		+-------------------------------+
	| |		| |
	| ACH Type = 0xA |		| ACH Type = 0xA |
	| |		| |
	+-------------------------------+		+-------------------------------+
	| |		| |
	| RFC 6374 Measurement Message |		| Measurement Message |
	| |		| |
	| +-------------------------+ |		| +-------------------------+ |
	| | | |		| | | |
	| | Fixed-format | |		| | Fixed-format | |
	| | portion of msg | |		| | portion of msg | |
	| | | |		| | | |
	| +-------------------------+ |		| +-------------------------+ |
	| | | |		| | | |
	| | Optional SFL TLV | |		| | Optional SFL TLV | |
	| | | |		| | | |
	| +-------------------------+ |		| +-------------------------+ |
	| | | |		| | | |
	| | Optional Return | |		| | Optional Return | |
	| | Information | |		| | Information | |
	| | | |		| | | |
	| +-------------------------+ |		| +-------------------------+ |
	| |		| |
	+-------------------------------+		+-------------------------------+
	Figure 5: RFC 6734 Query Packet with SFL		Figure 5: Query Packet with SFL
	The MPLS label stack is exactly the same as that used for the user		The MPLS label stack is exactly the same as that used for the user
	data service packets being instrumented except for the inclusion of		data service packets being instrumented except for the inclusion of
	the Generic Associated Channel Label (GAL) [RFC5586] to allow the		the Generic Associated Channel Label (GAL) [RFC5586] to allow the
	receiver to distinguish between normal data packets and OAM packets.		receiver to distinguish between normal data packets and OAM packets.
	Since the packet loss measurements are being made on the data service		Since the packet loss measurements are being made on the data service
	packets, an [RFC6374] Direct Loss Measurement is being made, which is		packets, an MPLS Direct Loss Measurement is being made, which is
	indicated by the type field in the Associated Channel Header (ACH)		indicated by the type field in the Associated Channel Header (ACH)
	(Type = 0x000A).		(Type = 0x000A).
	The measurement message as specified in [RFC6374] consists of three		The measurement message as specified in [RFC6374] consists of up to
	components. The first is the [RFC6374] fixed-format portion of the		three components as follows.
	message, which is carried over the ACH channel. The ACH channel type
	specifies the type of measurement being made (currently: loss, delay,
	or loss and delay) as specified in [RFC6374].
	Two optional TLVs MAY also be carried if needed. The first is the		* The fixed-format portion of the message is carried over the ACH
	SFL TLV specified in Section 9.1. This is used to provide the		channel. The ACH channel type specifies the type of measurement
	implementation with a reminder of the SFL that was used to carry the		being made (currently: loss, delay, or loss and delay) as
	[RFC6374] message. This is needed because a number of MPLS		specified in [RFC6374].
	implementations do not provide the MPLS label stack to the MPLS OAM
	handler. This TLV is required if [RFC6374] messages are sent over
	UDP [RFC7876]. This TLV MUST be included unless, by some method
	outside the scope of this document, it is known that this information
	is not needed by the [RFC6374] responder.
	The second set of information that may be needed is the return		* (Optional) The SFL TLV specified in Section 9.1 MAY be carried if
	information that allows the responder send the [RFC6374] response to		needed. It is used to provide the implementation with a reminder
	the Querier. This is not needed if the response is requested in band		of the SFL that was used to carry the message. This is needed
	and the MPLS construct being measured is a point-to-point LSP, but it		because a number of MPLS implementations do not provide the MPLS
	otherwise MUST be carried. The Return Address TLV is defined in		label stack to the MPLS OAM handler. This TLV is required if
	[RFC6374], and the optional UDP Return Object is defined in		messages are sent over UDP [RFC7876]. This TLV MUST be included
	[RFC7876].		unless, by some method outside the scope of this document, it is
			known that this information is not needed by the responder as
			specified in [RFC6374].
			* (Optional) The return information MAY be carried if needed. It
			allows the responder send the response (as specified in [RFC6374])
			to the Querier. This is not needed if the response is requested
			in band and the MPLS construct being measured is a point-to-point
			LSP, but it otherwise MUST be carried. The Return Address TLV is
			defined in [RFC6374], and the optional UDP Return Object is
			defined in [RFC7876].
	Where a measurement other than an MPLS Direct Loss Measurement is to		Where a measurement other than an MPLS Direct Loss Measurement is to
	be made, the appropriate [RFC6374] measurement message is used (for		be made, the appropriate measurement message is used (for example,
	example, one of the new types defined in this document), and this is		one of the new types defined in this document), and this is indicated
	indicated to the receiver by the use of the corresponding ACH type.		to the receiver by the use of the corresponding ACH type.
	9.1. Extending RFC 6374 with SFL TLV		9.1. Extending RFC 6374 with SFL TLV
	The [RFC6374] SFL TLV is shown in Figure 6. This contains the SFL		The [RFC6374] SFL TLV is shown in Figure 6. This contains the SFL
	that was carried in the label stack, the FEC that was used to		that was carried in the label stack, the FEC that was used to
	allocate the SFL, and the index (into the batch of SFLs that were		allocate the SFL, and the index (into the batch of SFLs that were
	allocated for the FEC) that corresponds to this SFL.		allocated for the FEC) that corresponds to this SFL.
	0 1 2 3		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		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
End of changes. 22 change blocks.
	64 lines changed or deleted		70 lines changed or added
This html diff was produced by rfcdiff 1.48.