< draft-ietf-ospf-af-alt-09.txt		draft-ietf-ospf-af-alt-10.txt >
	Network Working Group A. Lindem (Editor)		Network Working Group A. Lindem (Editor)
	Internet-Draft Ericsson		Internet-Draft Ericsson
	Intended status: Standards Track S. Mirtorabi		Intended status: Standards Track S. Mirtorabi
	Expires: May 21, 2010 A. Roy		Expires: June 18, 2010 A. Roy
	M. Barnes		M. Barnes
	Cisco Systems		Cisco Systems
	R. Aggarwal		R. Aggarwal
	Juniper Networks		Juniper Networks
	November 17, 2009		December 15, 2009
	Support of address families in OSPFv3		Support of address families in OSPFv3
	draft-ietf-ospf-af-alt-09.txt		draft-ietf-ospf-af-alt-10.txt
			Abstract
			This document describes a mechanism for supporting multiple address
			families in OSPFv3 using multiple instances. It maps an address
			family (AF) to an OSPFv3 instance using the Instance ID field in the
			OSPFv3 packet header. This approach is fairly simple and minimizes
			extensions to OSPFv3 for supporting multiple AFs.
	Status of this Memo		Status of this Memo
	This Internet-Draft is submitted to IETF in full conformance with the		This Internet-Draft is submitted to IETF in full conformance with the
	provisions of BCP 78 and BCP 79.		provisions of BCP 78 and BCP 79.
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF), its areas, and its working groups. Note that		Task Force (IETF), its areas, and its working groups. Note that
	other groups may also distribute working documents as Internet-		other groups may also distribute working documents as Internet-
	Drafts.		Drafts.
	skipping to change at page 1, line 37 ¶		skipping to change at page 1, line 45 ¶
	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."
	The list of current Internet-Drafts can be accessed at		The list of current Internet-Drafts can be accessed at
	http://www.ietf.org/ietf/1id-abstracts.txt.		http://www.ietf.org/ietf/1id-abstracts.txt.
	The list of Internet-Draft Shadow Directories can be accessed at		The list of Internet-Draft Shadow Directories can be accessed at
	http://www.ietf.org/shadow.html.		http://www.ietf.org/shadow.html.
	This Internet-Draft will expire on May 21, 2010.		This Internet-Draft will expire on June 18, 2010.
	Copyright Notice		Copyright Notice
	Copyright (c) 2009 IETF Trust and the persons identified as the		Copyright (c) 2009 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 in effect on the date of		Provisions Relating to IETF Documents
	publication of this document (http://trustee.ietf.org/license-info).		(http://trustee.ietf.org/license-info) in effect on the date of
	Please review these documents carefully, as they describe your rights		publication of this document. Please review these documents
	and restrictions with respect to this document.		carefully, as they describe your rights and restrictions with respect
			to this document. Code Components extracted from this document must
	Abstract		include Simplified BSD License text as described in Section 4.e of
			the Trust Legal Provisions and are provided without warranty as
	This document describes a mechanism for supporting multiple address		described in the BSD License.
	families in OSPFv3 using multiple instances. It maps an address
	family (AF) to an OSPFv3 instance using the Instance ID field in the
	OSPFv3 packet header. This approach is fairly simple and minimizes
	extensions to OSPFv3 for supporting multiple AFs.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
	1.1. Design Considerations . . . . . . . . . . . . . . . . . . 3		1.1. Design Considerations . . . . . . . . . . . . . . . . . . 3
	1.2. Requirements notation . . . . . . . . . . . . . . . . . . 3		1.2. Requirements notation . . . . . . . . . . . . . . . . . . 3
	2. Protocol Details . . . . . . . . . . . . . . . . . . . . . . . 4		2. Protocol Details . . . . . . . . . . . . . . . . . . . . . . . 4
	2.1. Instance ID values for new AFs . . . . . . . . . . . . . . 4		2.1. Instance ID values for new AFs . . . . . . . . . . . . . . 4
	2.2. OSPFv3 Options Changes . . . . . . . . . . . . . . . . . . 4		2.2. OSPFv3 Options Changes . . . . . . . . . . . . . . . . . . 4
	2.3. Advertising Prefixes in new AFs . . . . . . . . . . . . . 5		2.3. Advertising Prefixes in AFs other than IPv6 . . . . . . . 5
	2.4. Changes to the Hello processing . . . . . . . . . . . . . 5		2.4. Changes to the Hello processing . . . . . . . . . . . . . 5
	2.5. Next hop for IPv4 unicast and multicast AFs . . . . . . . 5		2.5. Next-Hop Calculation for IPv4 unicast and multicast AFs . 6
	2.6. AS External LSA Forwarding Address for IPv4 Unicast		2.6. AS External LSA Forwarding Address for IPv4 Unicast
	and IPv4 Multicast AFs . . . . . . . . . . . . . . . . . . 6		and IPv4 Multicast AFs . . . . . . . . . . . . . . . . . . 6
	2.7. Database Description Maximum Transmissoin Unit (MTU)		2.7. Database Description Maximum Transmission Unit (MTU)
	Specification for Non-IPv6 AFs . . . . . . . . . . . . . . 6		Specification for Non-IPv6 AFs . . . . . . . . . . . . . . 6
	2.8. Operation over Virtual Links . . . . . . . . . . . . . . . 9		2.8. Operation over Virtual Links . . . . . . . . . . . . . . . 8
	3. Backward Compatibility . . . . . . . . . . . . . . . . . . . . 10		3. Backward Compatibility . . . . . . . . . . . . . . . . . . . . 9
	4. Security Considerations . . . . . . . . . . . . . . . . . . . 11		4. Security Considerations . . . . . . . . . . . . . . . . . . . 10
	5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12		5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
	6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14		6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
	6.1. Normative References . . . . . . . . . . . . . . . . . . . 14		6.1. Normative References . . . . . . . . . . . . . . . . . . . 13
	6.2. Informative References . . . . . . . . . . . . . . . . . . 14		6.2. Informative References . . . . . . . . . . . . . . . . . . 13
	Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . . 15		Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . . 14
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15
	1. Introduction		1. Introduction
	OSPFv3 [OSPFV3] has been defined to support the base IPv6 unicast		OSPFv3 [OSPFV3] has been defined to support the base IPv6 unicast
	Address Family (AF). There are requirements to advertise other AFs		Address Family (AF). There are requirements to advertise other AFs
	in OSPFv3 including multicast IPv6, unicast IPv4, and multicast IPv4.		in OSPFv3 including multicast IPv6, unicast IPv4, and multicast IPv4.
	This document supports these other AFs in OSPFv3 by mapping each AF		This document supports these other AFs in OSPFv3 by mapping each AF
	to a separate Instance ID and OSPFv3 instance.		to a separate Instance ID and OSPFv3 instance.
	1.1. Design Considerations		1.1. Design Considerations
	skipping to change at page 4, line 14 ¶		skipping to change at page 4, line 14 ¶
	2. Protocol Details		2. Protocol Details
	Currently the entire Instance ID number space is used for IPv6		Currently the entire Instance ID number space is used for IPv6
	unicast. This specification assigns different Instance ID ranges to		unicast. This specification assigns different Instance ID ranges to
	different AFs in order to support other AFs in OSPFv3. Each Instance		different AFs in order to support other AFs in OSPFv3. Each Instance
	ID implies a separate OSPFv3 instance with its own neighbor		ID implies a separate OSPFv3 instance with its own neighbor
	adjacencies, link state database, protocol data structures, and		adjacencies, link state database, protocol data structures, and
	shortest path first (SPF) computation.		shortest path first (SPF) computation.
	Additionally, the current LSAs that are defined to advertise IPv6		Additionally, the current Link State Advertisements (LSAs) defined to
	unicast prefixes can be used without any modifications to advertise		advertise IPv6 unicast prefixes can be used to advertise prefixes
	prefixes from other AFs.		from other AFs without modification.
	It should be noted that OSPFv3 is running on top of IPv6 and uses		It should be noted that OSPFv3 runs on top of IPv6 and uses IPv6 link
	IPv6 link local addresses for OSPFv3 control packets. Therefore, it		local addresses for OSPFv3 control packets. Therefore, it is
	is required that IPv6 be enabled on a link, although the link may not		required that IPv6 be enabled on an OSPFv3 link, although the link
	be participating in any IPv6 AF.		may not be participating in any IPv6 AFs.
	2.1. Instance ID values for new AFs		2.1. Instance ID values for new AFs
	Instance ID zero is already defined by default for the IPv6 unicast		Instance ID zero is already defined by default for the IPv6 unicast
	AF. We define the following ranges for different AFs. The first		AF. When this specification is used to support multiple AFs, we
	value of each range is considered as the default value for the		define the following ranges for different AFs. The first value of
	corresponding AF.		each range is the default value for the corresponding AF.
	Instance ID # 0 - # 31 IPv6 unicast AF		Instance ID # 0 - # 31 IPv6 unicast AF
	Instance ID # 32 - # 63 IPv6 multicast AF		Instance ID # 32 - # 63 IPv6 multicast AF
	Instance ID # 64 - # 95 IPv4 unicast AF		Instance ID # 64 - # 95 IPv4 unicast AF
	Instance ID # 96 - # 127 IPv4 multicast AF		Instance ID # 96 - # 127 IPv4 multicast AF
	Instance ID # 128 - # 255 Unassigned		Instance ID # 128 - # 255 Unassigned
	OSPFv3 Instance IDs		OSPFv3 Instance IDs
	2.2. OSPFv3 Options Changes		2.2. OSPFv3 Options Changes
	A new AF-bit is added to the OSPFv3 options field. V6-bit and MC-bit		A new AF-bit is added to the OSPFv3 options field. The V6-bit is
	are only applicable to the IPv6 unicast AF.		only applicable to the IPv6 unicast AF.
	1 2		1 2
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 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
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+--+-+-+--+--+--+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+--+-+-+--+--+--+
	| | | | | | | | | | | | | | | |AF|*|*|DC|R|N|x | E|V6|		| | | | | | | | | | | | | | | |AF|*|*|DC|R|N|x | E|V6|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+--+-+-+--+--+--+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+--+-+-+--+--+--+
	The Options field		The Options field
	OSPFv3 Options		OSPFv3 Options
	V6-bit		V6-bit
	The V6 bit is used in OSPFv3 to exclude a node from IPv6 unicast		The V6 bit is used in OSPFv3 to exclude a node from IPv6 unicast
	route calculation but allow it in the SPF calculation for other		route calculation but allow it in the SPF calculation for other
	address families. Since Instance ID now denotes the AF		address families. Since Instance ID now denotes the AF
	explicitly, this bit is ignored in AFs other than IPv6 unicast.		explicitly, this bit is ignored in AFs other than IPv6 unicast.
	AF-bit		AF-bit
	When a router supports AF, it MUST set this new bit in the OSPFv3		When an OSPFv3 router is supporting AFs as described in this
	Options field of Hello Packets, DD packets, and LSAs.		specification, it MUST set the AF-bit in the OSPFv3 Options field
			of Hello Packets, Database Description packets, and LSAs.
	2.3. Advertising Prefixes in new AFs		2.3. Advertising Prefixes in AFs other than IPv6
	Each Prefix defined in OSPFv3 has a prefix length field. This		Each Prefix defined in OSPFv3 has a prefix length field. This
	facilitate advertising prefixes of different lengths in different		facilitates advertising prefixes of different lengths in different
	AFs. The existing LSAs defined in OSPFv3 are used for this purpose		AFs. The existing LSAs defined in OSPFv3 are used for this purpose
	and there is no need to define new LSAs.		and there is no need to define new LSAs.
	Prefixes which don't match the AF of the OSPFv3 instance, MUST be		Prefixes which don't conform to OSPFv3 instance AF MUST be not be
	discarded in any route computation.		used in the route computation for the instance.
	2.4. Changes to the Hello processing		2.4. Changes to the Hello processing
	When a router does not support an AF but it is configured with the		When an OSPFv3 router does not support this specification and it is
	corresponding Instance ID packets could be black holed. This could		configured with the corresponding Instance ID, packets could be black
	happen due to misconfiguration or a router software downgrade. Black		holed. This could happen due to misconfiguration or a router
	holing is possible because the router which doesn't support the AF		software downgrade. Black holing is possible because the router
	can still be included in the SPF calculated path as long as it		which doesn't support the AF can still be included in the SPF
	establishes adjacencies using the Instance ID corresponding to the		calculated path as long as it establishes adjacencies using the
	AF. Note that router and network LSAs are AF independent.		Instance ID corresponding to the AF. Note that Router-LSAs and
			Network-LSAs are AF independent.
	In order to avoid the above situation, hello processing is changed in		In order to avoid the above situation, hello processing is changed in
	order to only establish adjacencies with routers that have the AF-bit		order to only establish adjacencies with routers that have the AF-bit
	set in their Options field.		set in their Options field.
	Receiving Hello Packets is specified in section 3.2.2.1 of [OSPFV3].		Receiving Hello Packets is specified in section 3.2.2.1 of [OSPFV3].
	The following check is added to Hello reception:		The following check is added to Hello reception:
	o When a router participates in an AF (sets the AF-bit in Options		o When an OSPFv3 router participates in an AF (sets the AF-bit in
	field) it MUST discard Hello packets having the AF-bit clear in		Options field), it MUST discard Hello packets having the AF-bit
	the Options field. The only exception is the Base IPv6 unicast		clear in the Options field. The only exception is the Base IPv6
	AF, where this check MUST NOT be done (for backward		unicast AF, where this check MUST NOT be done (for backward
	compatibility).		compatibility).
	2.5. Next hop for IPv4 unicast and multicast AFs		2.5. Next-Hop Calculation for IPv4 unicast and multicast AFs
	OSPFv3 runs on top of IPv6 and uses IPv6 link local addresses for		OSPFv3 runs on top of IPv6 and uses IPv6 link local addresses for
	OSPFv3 control packets and next hop calculations. Although IPV6 link		OSPFv3 control packets and next-hop calculations. Although IPV6 link
	local addresses could be used as next hops for IPv4 address families,		local addresses could be used as next-hops for IPv4 address families,
	it is desirable to have IPv4 next hop addresses. For example, in		it is desirable to have IPv4 next-hop addresses. For example, in the
	IPv4 multicast having the next hop address the same as the Protocol		IPv4 multicast AF, the Protocol Independent Multicast (PIM) [PIM]
	Independent Multicast (PIM) [PIM] neighbor address (IPv4 address)		neighbor address and the next-hop address should both be IPv4
	makes it easier to determine which upstream neighbor to send a PIM		addresses in order for the Reverse Path Forwarding (RPF) lookup to
	join when doing a Reverse Path Forwarding (RPF) lookup. It is also		work correctly. Troubleshooting is also easier when the prefix
	easier for troubleshooting to have a next hop with the same AF.		address and next-hop address are in the same AF.
	In order to achieve this, the link's IPv4 address will be advertised		In order to achieve this, the link's IPv4 address will be advertised
	in the "link local address" field of the IPv4 instance's Link-LSA.		in the "link local address" field of the IPv4 instance's Link-LSA.
	This address is placed in the first 32 bit of "link local address"		This address is placed in the first 32 bit of "link local address"
	field and used for IPv4 next hop calculations. The remaining bits		field and is used for IPv4 next-hop calculations. The remaining bits
	MUST be set to zero.		MUST be set to zero.
	We call the direct interface address (DIA) the address that is		We call the direct interface address (DIA) the address that is
	reachable directly via the link provided that a layer 3 to layer 2		reachable directly via the link provided that a layer 3 to layer 2
	mapping is available. Note that there is no explicit need for the		mapping is available. Note that there is no explicit need for the
	IPv4 link addresses to be on the same subnet. An implementation		IPv4 link addresses to be on the same subnet. An implementation
	SHOULD resolve layer 3 to layer 2 mappings via Address Resolution		SHOULD resolve layer 3 to layer 2 mappings via Address Resolution
	Protocol (ARP) [ARP] or Neighbor Discovery (ND) [ND] for a DIA even		Protocol (ARP) [ARP] or Neighbor Discovery (ND) [ND] for a DIA even
	if the IPv4 address is not on the same subnet as the router's		if the IPv4 address is not on the same subnet as the router's
	interface IP address.		interface IP address.
	skipping to change at page 6, line 37 ¶		skipping to change at page 6, line 43 ¶
	Multicast AFs		Multicast AFs
	For OSPFv3, this address is an IPv6 host address (128 bits). If		For OSPFv3, this address is an IPv6 host address (128 bits). If
	included, data traffic for the advertised destination will be		included, data traffic for the advertised destination will be
	forwarded to this address. For IPv4 unicast and IPv4 multicast AFs,		forwarded to this address. For IPv4 unicast and IPv4 multicast AFs,
	the Forwarding Address in AS-external-LSAs MUST encode an IPv4		the Forwarding Address in AS-external-LSAs MUST encode an IPv4
	address. To achieve this, the IPv4 Forwarding Address is advertised		address. To achieve this, the IPv4 Forwarding Address is advertised
	by placing it in the first 32 bits of the Forwarding Address field in		by placing it in the first 32 bits of the Forwarding Address field in
	the AS-external-LSAs. The remaining bits MUST be set to zero.		the AS-external-LSAs. The remaining bits MUST be set to zero.
	2.7. Database Description Maximum Transmissoin Unit (MTU)		2.7. Database Description Maximum Transmission Unit (MTU)
	Specification for Non-IPv6 AFs		Specification for Non-IPv6 AFs
	For address families other than IPv6, both the MTU for the address		For address families other than IPv6, both the MTU for the instance
	family of the instance and IPv6 MTU used for OSPFv3 maximum packet		address family and IPv6 MTU used for OSPFv3 maximum packet
	determination MUST be considered. The MTU in the Database		determination MUST be considered. The MTU in the Database
	Description packet MUST always contain the MTU corresponding to the		Description packet MUST always contain the MTU corresponding to the
	advertised address family. For example, if the instance corresponds		advertised address family. For example, if the instance corresponds
	to an IPv4 address family, the IPv4 MTU for the interface MUST be		to an IPv4 address family, the IPv4 MTU for the interface MUST be
	specified in the interface MTU field. As specified section 10.6 of		specified in the interface MTU field. As specified section 10.6 of
	[OSPFV2], the Database Description packet will be rejected if the MTU		[OSPFV2], the Database Description packet will be rejected if the MTU
	is greater than the receiving interface's MTU for the address family		is greater than the receiving interface's MTU for the address family
	corresponding to the instance. This behavior will assure an		corresponding to the instance. This behavior will assure an
	adjacency is not formed and address family specific routes are not		adjacency is not formed and address family specific routes are not
	installed over a path with conflicting MTUs.		installed over a path with conflicting MTUs.
	The value used for OSPFv3 maximum packet size determination MUST also		The value used for OSPFv3 maximum packet size determination MUST also
	be compatible for an adjacency to be established. Since only a		be compatible for an adjacency to be established. Since only a
	single MTU field is specified, the M6-bit is defined by this		single MTU field is specified, the M6-bit is defined by this
	specification. If the M6-bit is clear, the specified MTU SHOULD also		specification. If the M6-bit is clear, the specified MTU SHOULD also
	be checked against the IPv6 MTU and the Database Description packet		be checked against the IPv6 MTU and the Database Description packet
	SHOULD be rejected if the MTU is larger than the receiving		SHOULD be rejected if the MTU is larger than the receiving
	interface's IPv6 MTU. An OSPFv3 router SHOULD NOT set the M6-bit if		interface's IPv6 MTU. An OSPFv3 router SHOULD NOT set the M6-bit if
	its IPv6 MTU and address family specific MTU are the same.		its IPv6 MTU and address family specific MTU are the same.
	If the IPv6 and IPv4 MTUs differ, the M6-bit MUST be set for non-IPv6		If the IPv6 and IPv4 MTUs differ, the M6-bit MUST be set for non-IPv6
	address families. If the M6-bit is set, the IPv6 MTU is decided by		address families. If the M6-bit is set, the IPv6 MTU is decided by
	the presence or absense of IPv6 MTU TLV in the LLS [LLS] block. If		the presence or absence of an IPv6 MTU TLV in the LLS [LLS] block.
	this TLV is present, it carries the IPv6 MTU which SHOULD be compared		If this TLV is present, it carries the IPv6 MTU that SHOULD be
	with local IPv6 MTU. If this TLV is absent, the minimum IPv6 MTU of		compared with local IPv6 MTU. If this TLV is absent, the minimum
	1280 octets SHOULD be used for the comparison (refer to [IPV6]).		IPv6 MTU of 1280 octets SHOULD be used for the comparison (refer to
			[IPV6]).
	If the M6-bit is set in a received Database Description packet for a		If the M6-bit is set in a received Database Description packet for a
	non-IPv6 address family, the receiving router MUST NOT check the		non-IPv6 address family, the receiving router MUST NOT check the
	Interface MTU in the Database Exchange packet against the receiving		Interface MTU in the Database Description packet against the
	interface's IPv6 MTU.		receiving interface's IPv6 MTU.
	The figure below graphically depicts the OSPFv3 Database Description		The figure below graphically depicts the changed fields in the octets
	Packet:		20-23 of the OSPFv3 Database Description Packet:
	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
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+--+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+--+
	| 3 | 2 | Packet Length |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+--+
	| Router ID |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+--+
	| Area ID |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+--+
	| Checksum | Instance ID | 0 |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+--+
	| 0 | Options |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+--+
	| Interface MTU | 0 |0|0|0|M6|0|I|M|MS|		| Interface MTU | 0 |0|0|0|M6|0|I|M|MS|
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+--+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+--+
	| DD sequence number |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+--+
	| |
	+- -+
	| |
	+- An LSA Header -+
	| |
	+- -+
	| |
	+- -+
	| |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+-+-+-+--+
	| ... |
	The OSPFv3 Database Description Packet		OSPFv3 Database Description Packet Changes
	The changed fields in the Database Description packet are described		The changed fields in the Database Description packet are described
	below. The remaining fields are unchanged from [OSPFV3].		below. The remaining fields are unchanged from [OSPFV3].
	Interface MTU		Interface MTU
	The size in octets of the largest address-family specific datagram		The size in octets of the largest AF specific datagram that can be
	that can be sent out the associated interface without		sent on the associated interface without fragmentation. The MTUs
	fragmentation. The MTUs of common Internet link types can be		of common Internet link types can be found in Table 7-1 of
	found in Table 7-1 of [MTUDISC]. Interface MTU SHOULD be set to 0		[MTUDISC]. Interface MTU SHOULD be set to 0 in Database
	in Database Description packets sent over virtual links.		Description packets sent over virtual links.
	M6-bit		M6-bit
	The IPv6 MTU bit - this bit indicates the sender is using a		The IPv6 MTU bit - this bit indicates the sender is using a
	different IPv6 MTU than the MTU for the address family.		different IPv6 MTU than the MTU for the AF.
	IPv6 MTU TLV can be optionally carried in LLS block as described		An IPv6 MTU TLV can be optionally carried in LLS block as described
	above. This TLV carries the IPv6 MTU on the interface. The length		above. This TLV carries the IPv6 MTU for the interface. The length
	field of of TLV is set to 4 bytes.		field of the TLV is set to 4 bytes.
	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
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| 6 (TBD) | 4 |		| 6 (TBD) | 4 |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| IPv6 MTU |		| IPv6 MTU |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Format of IPv6 MTU TLV		Format of IPv6 MTU TLV
	The IPv6 MTU TLV may appear in the LLS block only once.		Only one instance of the IPv6 MTU TLV MAY appear in the LLS block.
			Instances subsequent to the first are not processed and the LLS
			inconsistency SHOULD be logged.
	2.8. Operation over Virtual Links		2.8. Operation over Virtual Links
	OSPFv3 control packets sent over a virtual link are IPv6 packets and		OSPFv3 control packets sent over a virtual link are IPv6 packets and
	may traverse multiples hops. Therefore, there MUST be a global IPv6		may traverse multiples hops. Therefore, there MUST be a global IPv6
	address associated with the virtual link so that the control packet		address associated with the virtual link so that OSPFv3 control
	is forwarded correctly by the intermediate hops between virtual link		packets are forwarded correctly by the intermediate hops between
	endpoints. Although this requirement can be satisfied in IPv6		virtual link endpoints. Although this requirement can be satisfied
	unicast AFs, it will not function in other AFs as there will not be a		in IPv6 unicast AFs, it will not function in other AFs as there will
	routable global IPv6 address or forwarding path. Therefore, virtual		not be a routable global IPv6 address or forwarding path. Therefore,
	links are not supported in AFs other than IPv6 Unicast.		virtual links are not supported in AFs other than IPv6 Unicast.
	3. Backward Compatibility		3. Backward Compatibility
			All modifications to OSPFv3 apply exclusively to the support address
			families other than IPv6 unicast using multiple OSPFv3 instances as
			described in this specification. They are not applicable to IPv6
			unicast topologies and do not preclude future single instance
			mechanisms for supporting multiple address families.
	In this section, we will define a non-capable OSPFv3 router as one		In this section, we will define a non-capable OSPFv3 router as one
	not supporting this specification. Each new AF will have a		not supporting this specification. When multiple AFs are supported
	corresponding Instance ID and can interoperate with the existing non-		as defined herein, each new AF will have a corresponding Instance ID
	capable OSPFv3 routers in an IPv6 unicast topology. Furthermore,		and can interoperate with the existing non-capable OSPFv3 routers in
	when a non-capable OSPFv3 router uses an Instance ID which is		an IPv6 unicast topology. Furthermore, when a non-capable OSPFv3
	reserved for a given AF, no adjacency will be formed with this router		router uses an Instance ID that is reserved for a given AF, no
	since the AF-bit in the Options field will not be set in Hello		adjacency will be formed with this router since the AF-bit in the
	packets. Therefore, there are no backward compatibility issues. AFs		Options field will be clear in its OSPFv3 Hello packets. Therefore,
	can be gradually deployed without disturbing networks with non-		there are no backward compatibility issues. AFs can be gradually
	capable OSPFv3 routers.		deployed without disturbing OSPFv3 routing domains with non-capable
			OSPFv3 routers.
	4. Security Considerations		4. Security Considerations
	IPsec [IPsec] can be used for OSPFv3 authentication and		IPsec [IPsec] can be used for OSPFv3 authentication and
	confidentiality as described in [OSPFV3-AUTH]. When multiple OSPFv3		confidentiality as described in [OSPFV3-AUTH]. When multiple OSPFv3
	instances use the same interface, they all MUST use the same Security		instances use the same interface, they all MUST use the same Security
	Association (SA), since the SA selectors do not provide selection		Association (SA), since the SA selectors do not provide selection
	based on OSPFv3 header fields such as the instance ID. This		based on OSPFv3 header fields, such as the Instance ID. This
	restriction is documented in section 8 of [OSPFV3-AUTH].		restriction is documented in section 8 of [OSPFV3-AUTH].
	Security considerations for the OSPFv3 are covered in [OSPFV3].		Security considerations for the OSPFv3 are covered in [OSPFV3].
	5. IANA Considerations		5. IANA Considerations
	The following IANA assignments are to be made from existing		The following IANA assignments are to be made from existing
	registries:		registries:
	The AF-bit is assigned from OSPFv3 Options field as defined in		The AF-bit is assigned from OSPFv3 Options field as defined in
	Section 2.2.		Section 2.2.
	IANA is requested to create a new registry, "OSPFv3 Instance ID		IANA is requested to create a new registry, "OSPFv3 Instance ID
	Address Family Values". for assignment of address families. Note		Address Family Values", for assignment of the mapping of OSPFv3
	that the Instance ID MAY be used for applications other than the		Instance ID to address families when this specification is used to
	support of multiple address families. However, if it is being used		support multiple address families. Note that the Instance ID field
	for address families the assignments herein SHOULD be honored.		MAY be used for applications other than the support of multiple
			address families. However, if it is being used for address families
			as described in this specification, the assignments herein SHOULD be
			honored.
	+-------------+----------------------+--------------------+		+-------------+----------------------+--------------------+
	| Value/Range | Designation | Assignment Policy |		| Value/Range | Designation | Assignment Policy |
	+-------------+----------------------+--------------------+		+-------------+----------------------+--------------------+
	| 0 | Base IPv6 Unicast AF | Already assigned |		| 0 | Base IPv6 Unicast AF | Already assigned |
	| | | |		| | | |
	| 1-31 | IPv6 Unicast AFs | Already assigned |		| 1-31 | IPv6 Unicast AFs | Already assigned |
	| | dependent on local | |		| | dependent on local | |
	| | policy | |		| | policy | |
	| | | |		| | | |
	skipping to change at page 15, line 10 ¶		skipping to change at page 14, line 10 ¶
	[PIM] Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas,		[PIM] Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas,
	"Protocol Independent Multicast - Sparse Mode (PIM-SM):		"Protocol Independent Multicast - Sparse Mode (PIM-SM):
	Protocol Specification (Revised)", RFC 4601, August 2006.		Protocol Specification (Revised)", RFC 4601, August 2006.
	Appendix A. Acknowledgments		Appendix A. Acknowledgments
	The RFC text was produced using Marshall Rose's xml2rfc tool.		The RFC text was produced using Marshall Rose's xml2rfc tool.
	Thanks to Tom Henderson and the folks at Boeing for implementing in		Thanks to Tom Henderson and the folks at Boeing for implementing in
	quagga.		the Quagga routing suite, http:www.quagga.net.
	Thanks to Nischal Sheth for review and comments.		Thanks to Nischal Sheth for review and comments.
			Thanks to Christian Vogt for comments during the Gen-ART review.
			Thanks to Adrian Farrel for comments during the IESG review.
	Authors' Addresses		Authors' Addresses
	Acee Lindem		Acee Lindem
	Ericsson		Ericsson
	102 Carric Bend Court		102 Carric Bend Court
	Cary, NC 27519		Cary, NC 27519
	USA		USA
	Email: acee.lindem@ericsson.com		Email: acee.lindem@ericsson.com
End of changes. 42 change blocks.
	133 lines changed or deleted		134 lines changed or added
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