draft-ietf-mpls-rfc8287-len-clarification-02.txt		draft-ietf-mpls-rfc8287-len-clarification-03.txt
	Network Work group N. Nainar		Network Work group N. Nainar
	Internet-Draft C. Pignataro		Internet-Draft C. Pignataro
	Updates: 8287 (if approved) Cisco Systems, Inc.		Updates: 8287 (if approved) Cisco Systems, Inc.
	Intended status: Standards Track F. Iqbal		Intended status: Standards Track F. Iqbal
	Expires: December 2, 2019 Individual		Expires: February 9, 2020 Individual
	A. Vainshtein		A. Vainshtein
	ECI Telecom		ECI Telecom
	May 31, 2019		August 8, 2019
	RFC8287 Sub-TLV Length Clarification		RFC8287 Sub-TLV Length Clarification
	draft-ietf-mpls-rfc8287-len-clarification-02		draft-ietf-mpls-rfc8287-len-clarification-03
	Abstract		Abstract
	RFC8287 defines the extensions to MPLS LSP Ping and Traceroute for		RFC8287 defines the extensions to MPLS LSP Ping and Traceroute for
	Segment Routing IGP-Prefix and IGP-Adjacency Segment Identifier		Segment Routing IGP-Prefix and IGP-Adjacency Segment Identifier
	(SIDs) with an MPLS data plane. RFC8287 proposes 3 Target FEC Stack		(SIDs) with an MPLS data plane. RFC8287 proposes 3 Target FEC Stack
	Sub-TLVs. While the standard defines the format and procedure to		Sub-TLVs. While the standard defines the format and procedure to
	handle those Sub-TLVs, it does not sufficiently clarify how the		handle those Sub-TLVs, it does not sufficiently clarify how the
	length of the Segment ID Sub-TLVs should be computed to include in		length of the Segment ID Sub-TLVs should be computed to include in
	the Length field of the Sub-TLVs which may result in interoperability		the Length field of the Sub-TLVs which may result in interoperability
	skipping to change at page 1, line 44 ¶		skipping to change at page 1, line 44 ¶
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at https://datatracker.ietf.org/drafts/current/.		Drafts is at https://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on December 2, 2019.		This Internet-Draft will expire on February 9, 2020.
	Copyright Notice		Copyright Notice
	Copyright (c) 2019 IETF Trust and the persons identified as the		Copyright (c) 2019 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(https://trustee.ietf.org/license-info) in effect on the date of		(https://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	skipping to change at page 3, line 15 ¶		skipping to change at page 3, line 15 ¶
	2. Terminology		2. Terminology
	This document uses the terminologies defined in [RFC8402], [RFC8029],		This document uses the terminologies defined in [RFC8402], [RFC8029],
	[RFC8287] and so the readers are expected to be familiar with the		[RFC8287] and so the readers are expected to be familiar with the
	same.		same.
	3. Requirements notation		3. Requirements notation
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this		"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
	document are to be interpreted as described in [RFC2119] [RFC8174].		document are to be interpreted as described in [RFC2119] [RFC8174]
			when, and only when, they appear in all capitals, as shown here.
	4. Length field clarification for Segment ID Sub-TLVs		4. Length field clarification for Segment ID Sub-TLVs
	Section 5 of [RFC8287] defines 3 different Segment ID Sub-TLVs that		Section 5 of [RFC8287] defines 3 different Segment ID Sub-TLVs that
	will be included in Target FEC Stack TLV defined in [RFC8029]. The		will be included in Target FEC Stack TLV defined in [RFC8029]. The
	length of each Sub-TLVs MUST be calculated as defined in this		length of each Sub-TLVs MUST be calculated as defined in this
	section.		section.
	The figures in section 5.1, 5.2 and 5.3 of [RFC8287] are replaced by		The TLVs representation defined in section 5.1, 5.2 and 5.3 of
	the below figures in section 4.1, 4.2 and 4.3 respectively. The		[RFC8287] are updated to clarify the length calculation as shown in
	updated figures contain explicitly defined length.		section 4.1, 4.2 and 4.3 respectively. The updated TLV
			representation contain explicitly defined length.
	4.1. IPv4 IGP-Prefix Segment ID Sub-TLV		4.1. IPv4 IGP-Prefix Segment ID Sub-TLV
	The Sub-TLV length for IPv4 IGP-Prefix Segment ID MUST be set to 8 as		The Sub-TLV length for IPv4 IGP-Prefix Segment ID MUST be set to 8 as
	shown in the below TLV format:		shown in the below TLV format:
	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
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|Type = 34 (IPv4 IGP-Prefix SID)| Length = 8 |		|Type = 34 (IPv4 IGP-Prefix SID)| Length = 8 |
	skipping to change at page 4, line 8 ¶		skipping to change at page 4, line 8 ¶
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	4.2. IPv6 IGP-Prefix Segment ID Sub-TLV		4.2. IPv6 IGP-Prefix Segment ID Sub-TLV
	The Sub-TLV length for IPv6 IGP-Prefix Segment ID MUST be set to 20		The Sub-TLV length for IPv6 IGP-Prefix Segment ID MUST be set to 20
	as shown in the below TLV format:		as shown in the below TLV format:
	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
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|Type = 35 (IPv4 IGP-Prefix SID)| Length = 20 |		|Type = 35 (IPv6 IGP-Prefix SID)| Length = 20 |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| |		| |
	| |		| |
	| IPv6 Prefix |		| IPv6 Prefix |
	| |		| |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|Prefix Length | Protocol | Reserved |		|Prefix Length | Protocol | Reserved |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	4.3. IGP-Adjacency Segment ID Sub-TLV		4.3. IGP-Adjacency Segment ID Sub-TLV
	The Sub-TLV length for IGP-Adjacency Segment ID varies depending on		The Sub-TLV length for IGP-Adjacency Segment ID varies depending on
	the Adjacency Type and Protocol. In any of the allowed combination		the Adjacency Type and Protocol. In any of the allowed combination
	of Adjacency Type and Protocol, the sub-TLV length MUST be calculated		of Adjacency Type and Protocol, the sub-TLV length MUST be calculated
	by including 2 octets of Reserved field. Below is a table that list		by including 2 octets of Reserved field. Table 1 below list the
	the length for different combinations.		length for different combinations of Adj.Type and Protocol.
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Protocol | Length for Adj.Type |		| Protocol | Length for Adj.Type |
	+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| | Parallel | IPv4 | IPv6 |		| | Parallel | IPv4 | IPv6 | Unnumbered|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| OSPF | 20 | 20 | 44 |		| OSPF | 20 | 20 | 44 | 20 |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| ISIS | 24 | 24 | 48 |		| ISIS | 24 | 24 | 48 | 24 |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Any | 20 | 20 | 44 |		| Any | 20 | 20 | 44 | 20 |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
			Table 1. IGP-Adjacency SID Length Comparison
	For example, when the Adj. Type is set to Parallel Adjacency and the		For example, when the Adj. Type is set to Parallel Adjacency and the
	Protocol is set to 0, the Sub-TLV will be as below:		Protocol is set to 0, the Sub-TLV will be as below:
	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
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	|Type = 36 (IGP-Adjacency SID) | Length = 20 |		|Type = 36 (IGP-Adjacency SID) | Length = 20 |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Adj. Type = 1 | Protocol =0 | Reserved |		| Adj. Type = 1 | Protocol = 0 | Reserved |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Local Interface ID (4 octets) |		| Local Interface ID (4 octets) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Remote Interface ID (4 octets) |		| Remote Interface ID (4 octets) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Advertising Node Identifier (4 octets) |		| Advertising Node Identifier (4 octets) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Receiving Node Identifier (4 octets) |		| Receiving Node Identifier (4 octets) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	5. IANA Considerations		5. IANA Considerations
	This document does not introduce any IANA consideration.		This document does not introduce any IANA consideration.
	6. Security Considerations		6. Security Considerations
	This document updates [RFC8287] and does not introduce any security		This document updates [RFC8287] and does not introduce any additional
	considerations.		security considerations.
	7. Contributors		7. Contributors
	The below individuals contributed to this document:		The below individuals contributed to this document:
	Zafar Ali, Cisco Systems, Inc.		Zafar Ali, Cisco Systems, Inc.
	8. Acknowledgement		8. Acknowledgement
	The authors would like to thank Michael Gorokhovsky and Manohar		The authors would like to thank Michael Gorokhovsky and Manohar
End of changes. 11 change blocks.
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