Network Working Group W A Simpson Internet Draft Daydreamer expires in six months January 1995 IPv6 Neighbor Discovery -- ICMP Message Formats draft-simpson-ipv6-discov-formats-02.txt Status of this Memo This document is a submission to the IPng Working Group of the Internet Engineering Task Force (IETF). Comments should be submitted to the ipng@sunroof.eng.sun.com mailing list. Distribution of this memo is unlimited. This document is an Internet-Draft. Internet Drafts are working documents of the Internet Engineering Task Force (IETF), its Areas, and its Working Groups. Note that other groups may also distribute working documents as Internet Drafts. Internet Drafts are draft documents valid for a maximum of six months, and may be updated, replaced, or obsoleted by other documents at any time. It is not appropriate to use Internet Drafts as reference material, or to cite them other than as a ``working draft'' or ``work in progress.'' To learn the current status of any Internet-Draft, please check the ``1id-abstracts.txt'' listing contained in the internet-drafts Shadow Directories on: ftp.is.co.za (Africa) nic.nordu.net (Europe) ds.internic.net (US East Coast) ftp.isi.edu (US West Coast) munnari.oz.au (Pacific Rim) Abstract This document specifies ICMP messages for identification of and forwarding to adjacent IPv6 nodes, including Mobility, Next Hop Determination and Router Discovery. Simpson expires in six months [Page i] DRAFT IPv6 Discovery Formats January 1995 1. Additional ICMP Packets The datagram format and basic facilities are already defined for ICMP as modified for IPv6 [IPv6-ICMP]. Up-to-date values of the ICMP Type field are specified in the most recent "Assigned Numbers" [RFC-1700]. This document concerns the following values: 33 Where-Are-You Solicitations 34 I-Am-Here Advertisements Simpson expires in six months [Page 1] DRAFT IPv6 Discovery Formats January 1995 1.1. Where-Are-You Solicitations +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Code | Checksum | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extensions ... +-+-+-+-+-+-+-+-+-+-+-+- Type 33 Code Up-to-date values are specified in the most recent "Assigned Numbers" [RFC-1700]. Current values are assigned as follows: 0 RESERVED 1 General 2 Router 3 Service (reserved) Checksum The ICMP Checksum. Extensions zero or more Extensions. This field is variable in length. The Extensions SHOULD be included in the order described. These Extensions are described in a later chapter. The contents of the Reserved field MUST be zero on transmission, and MUST be ignored on receipt. Future backward-compatible changes to the protocol may specify the contents of the Reserved field or of additional octets at the end of the message. Simpson expires in six months [Page 2] DRAFT IPv6 Discovery Formats January 1995 1.1.1. General Solicitation The General Solicitation MUST contain at least the following values: Link Header (if any): Destination the link equivalent of the Solicited-Nodes IPv6 Multicast Address. The mapping is described in [IPv6-Address]. IPv6 Header: Destination the calculated Solicited-Nodes IPv6 Multicast Address. The scope is intra-link. This is calculated by starting with the exclusive-or of each byte of the target IPv6 Unicast Address, then adding the result to the base Solicited-Nodes multicast (FF02::0700). For example, to calculate the destination value for target A::B:C, the exclusive-or is D. The calculated destination would be FF02::070D. Source any IPv6 Unicast Address associated with the sending interface. It MUST NOT be the Unspecified Address. Hop Limit 1 ICMP fields: Code 1 for General Solicitation. Extensions: Known-Identifier any IPv6 Unicast Address of the target. The Prefix Size and Metric are always zero. Maximum-Receive-Unit for interfaces which do not have a fixed hardware MTU. Media-Access for interfaces which are not point-to-point links. Node-Heard for the target of the General Solicitation, if an advertisement has been heard. Simpson expires in six months [Page 3] DRAFT IPv6 Discovery Formats January 1995 In addition, each Router Advertisement that has been heard, in order of preference. In the unlikely event that not all extensions fit in a single solicitation, as constrained by the MTU of the link, the remaining extensions are removed. The use of the General Solicitation is described in [D-Send]. Simpson expires in six months [Page 4] DRAFT IPv6 Discovery Formats January 1995 1.1.2. Router Solicitation The Router Solicitation MUST contain at least the following values: Link Header (if any): Destination the link equivalent of the All-Routers IPv6 Multicast Address. The mapping is described in [IPv6-Address]. IPv6 Header: Destination the All-Routers IPv6 Multicast Address (FF02::3). The scope is intra-link. Source any IPv6 Unicast Address associated with the sending interface. It MAY be the Unspecified Address, when the node has not yet determined an IPv6 Unicast Address. Hop Limit 1 ICMP fields: Code 2 for Router Solicitation. Extensions: Maximum-Receive-Unit for interfaces which do not have a fixed hardware MTU. Media-Access for interfaces which are not point-to-point links. The use of the Router Solicitation is described in [D-Send]. Simpson expires in six months [Page 5] DRAFT IPv6 Discovery Formats January 1995 1.2. I-Am-Here Advertisements +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Code | Checksum | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence Number | LifeTime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extensions ... +-+-+-+-+-+-+-+-+-+-+-+- Type 34 Code Up-to-date values are specified in the most recent "Assigned Numbers" [RFC-1700]. Current values are assigned as follows: 0 RESERVED 1 General 2 Router 3 Service (reserved) 4 Local Redirect 5 Remote Redirect Checksum The ICMP Checksum. Sequence Number the number of Advertisement messages sent since the node was initialized. The value MUST include this advertisement. That is, the first Advertisement contains the value one, and the value zero indicates that the number has rolled over. LifeTime the time remaining before the advertised information is considered expired, in hundredths of seconds. The maximum time is approximately 10 minutes. Extensions zero or more Extensions. This field is variable in length. The Extensions SHOULD be included in the order described. These Extensions are described in a later chapter. Simpson expires in six months [Page 6] DRAFT IPv6 Discovery Formats January 1995 1.2.1. General Advertisement The General Advertisement MUST contain at least the following values: IPv6 Header: Destination the Source specified in the solicitation, when the node is not serving several neighbors, and the node is not operating as a Mobile Node. Otherwise, the All-Nodes IPv6 Multicast Address (FF02::1). The scope is intra-link. These decisions are described in [D-Send]. Source the Identifier specified in the Known-Identifier extension of the solicitation. Hop Limit 1 ICMP fields: Code 1 for General Advertisement. Lifetime the interface's configured AdvertisementLifetime. Extensions: Maximum-Receive-Unit for interfaces which do not have a fixed hardware MTU. Media-Access for interfaces which are not point-to-point links. Known-Identifier for each of that node's known IPv6 Unicast Addresses other than the IPv6 Unicast Address specified in the IPv6 Source field. The Prefix Size and Metric are always zero. This supports multiple addresses per interface, as well as multi-homed nodes. This enables the recipient node to determine the best next-hop, when the next-hop is on another interface attached to the same advertising node. Node-Heard for the sender of the General Solicitation. In addition, each Router Advertisement that has Simpson expires in six months [Page 7] DRAFT IPv6 Discovery Formats January 1995 been heard, in order of preference. In the unlikely event that not all extensions fit in a single advertisement, as constrained by the MTU of the link, the remaining extensions are removed. The use of the General Advertisement is described in [D-Send]. Simpson expires in six months [Page 8] DRAFT IPv6 Discovery Formats January 1995 1.2.2. Router Advertisement The Router Advertisement MUST contain at least the following values: IPv6 Header: Destination the All-Nodes IPv6 Multicast Address (FF02::1). The scope is intra-link. Source the Primary Identifier of the router. The same IPv6 Unicast Address is used for all interfaces. When a router has more than one interface on the same link, or a multi-homed host can hear the same router on more than one link, it is necessary to unambiguously know which router sent this advertisement. The individual routing-prefixes for the links are distinguished in the Prefix-Information extension. Hop Limit 1 ICMP fields: Code 2 for Router Advertisement. Lifetime the interface's configured AdvertisementLifetime. Extensions: Hop-Limit the current Internet Time-To-Live. Maximum-Receive-Unit for interfaces which do not have a fixed hardware MTU. Media-Access for interfaces which are not point-to-point links. Mobility-Support for interfaces which support Mobile Registration, either as a Foreign Agent or Home Agent [Mobility]. In the absence of this extension, all routers are expected to support decapsulation and forwarding from an interface, without explicit registration by a Mobile Node. Simpson expires in six months [Page 9] DRAFT IPv6 Discovery Formats January 1995 Change-Identifier for each of that interface's IPv6 Unicast or Cluster Addresses which has changed from a value previously advertised with the Prefix-Information or Known-Identifier extensions. Included at least once, and repeated until the original LifeTime expires. Prefix-Information for each of that interface's associated IPv6 Unicast or Cluster Addresses whose Advertise flags are TRUE. Known-Identifier for each of that node's other IPv6 Unicast or Cluster Addresses which have not already been included through routing-prefix subsumption. This may be another address for the same interface, or may identify another interface on the same node, or may proxy for another node. When a number of interfaces, such as point-to- point interfaces, may be aggregated with the same routing-prefix, only one extension need be included. Node-Heard for each Router Advertisement that has been heard, in order of preference. In the unlikely event that not all extensions fit in a single advertisement, as constrained by the MTU of the link, multiple advertisements are sent, with each containing as many remaining extensions as can fit. The use of the Router Advertisement is described in [D-Send]. Simpson expires in six months [Page 10] DRAFT IPv6 Discovery Formats January 1995 1.2.3. Local Redirect The Local Redirect MUST contain at least the following values: IPv6 Header: Destination the Source specified in the datagram being redirected. Source the Primary Identifier of the router. Hop Limit 1 Flow Label When the redirect applies to a single flow, this is set to a non-zero value. Note that this value is relative to the Destination specified in the datagram being redirected. ICMP fields: Code 4 for Local Redirect. Sequence the last Sequence from the target node Advertisement. Lifetime the remaining Lifetime from the target node Advertisement. Extensions: Maximum-Receive-Unit for interfaces which do not have a fixed hardware MTU, the Maximum-Receive-Unit extension from the target node Advertisement. Media-Access for interfaces which are not point-to-point links, the Media-Access extension from the target node Advertisement. Known-Identifier for each IPv6 Unicast or Cluster Address associated with the changed node(s). The Metric is always zero. When the redirect applies to an entire routing- prefix, the Prefix Size is set to the size of the routing-prefix. This enables the recipient node Simpson expires in six months [Page 11] DRAFT IPv6 Discovery Formats January 1995 to determine the best next-hop without multiple redirects for each routing-prefix. Redirected-Header The target header. In the unlikely event that not all extensions fit in a single redirect, as constrained by the MTU of the link, the remaining extensions are removed. Only a single redirect is sent. The use of the Local Redirect is described in [D-Send]. Simpson expires in six months [Page 12] DRAFT IPv6 Discovery Formats January 1995 1.2.4. Remote Redirect The Remote Redirect MUST contain at least the following values: IPv6 Header: Destination the Source specified in the packet being redirected. Source the Destination specified in the packet being redirected. Hop Limit from the Router Advertisement. An Authentication Header is required. ICMP fields: Code 5 for Remote Redirect. Sequence the last Sequence from the target node Advertisement. Lifetime the remaining Lifetime from the target node Advertisement. Extensions: Known-Identifier the IPv6 Unicast or Cluster Address which is used as a Care-Of-Address to reach the Source. Redirected-Header The target header. In the unlikely event that not all extensions fit in a single redirect, as constrained by the MTU of the link, the remaining extensions are removed. Only a single redirect is sent. The use of the Remote Redirect is described in [D-Send]. Simpson expires in six months [Page 13] DRAFT IPv6 Discovery Formats January 1995 2. Extensions Extensions allow variable amounts of information to be carried within each Solicitation or Advertisement packet. Some extensions are common to both packet types. The end of the list of Extensions is indicated by the Payload Length of the IPv6 packet. +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- | Extension | Length | Data ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- Extension This document concerns the following values: 0 Single Pad (no length field) 1 Multiple Pads (with length field) 2 Change-Identifier 3 Known-Identifier 4 Node-Heard 5 Prefix-Information 13 Hop-Limit 14 Maximum-Receive-Unit 15 Media-Access 16 Mobility-Support 254 Redirected-Header Up-to-date values are specified in the most recent "Assigned Numbers" [RFC-1700]. Length the length of the Data field. The Length does not include the Extension and Length octets. The Single Pad (extension 0) is a special case, which has neither Length field nor Data field. Data zero or more octets. The format and length of the Data field is determined by the Extension and Length fields. When an extension is encountered which is not recognized, it is ignored. The Length field is used to skip the data field in searching for the next extension. Every extension is aligned such that internal fields fall on natural boundaries, except that fields larger than 64-bits need only be aligned to 64-bit boundaries. Simpson expires in six months [Page 14] DRAFT IPv6 Discovery Formats January 1995 Any unused portion of the datagram between such Extensions is padded as appropriate. The final Extension in a datagram does not require trailing padding. 2.1. Single Pad +-+-+-+-+-+-+-+-+ | Extension | +-+-+-+-+-+-+-+-+ Extension 0 2.2. Multiple Pads +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- | Extension | Length | Data ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- Extension 1 Length the length of the Data field. Data zero or more bytes of zeroes. Simpson expires in six months [Page 15] DRAFT IPv6 Discovery Formats January 1995 2.3. Change-Identifier +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extension | Length | 0 | Prefix Size | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | ~ Identifier ~ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Extension 2 Length 34 Prefix Size the number of bits in the Identifier which define the routing-prefix width for the link. The value ranges from 0 to 127. If the Identifier does not indicate a valid prefix, the value is zero. Identifier an IPv6 Unicast or Cluster Address. For usage, see the specific message description, and [D-Send]. Simpson expires in six months [Page 16] DRAFT IPv6 Discovery Formats January 1995 2.4. Known-Identifier +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extension | Length | 0 | Prefix Size | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Metric | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | ~ Identifier ~ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Extension 3 Length 22 Prefix Size the number of bits in the Identifier which define the routing-prefix width for the link. The value ranges from 0 to 127. If the Identifier does not indicate a valid prefix, the value is zero. Metric the preference level for use of this node to forward packets to the Identifier. Lower values indicate greater preference. Identifier an IPv6 Unicast or Cluster Address. For usage, see the specific message description, and [D-Send]. Simpson expires in six months [Page 17] DRAFT IPv6 Discovery Formats January 1995 2.5. Node-Heard +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extension | Length | 0 | Prefix Size | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence Number | Remaining LifeTime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | ~ Primary Identifier ~ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MRU | 0 | Speed | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Quality | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Advertisement Count | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Error Count | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Extension 4 Length 38 Prefix Size the number of bits in the Primary Identifier which define the routing-prefix width for the link. The value ranges from 0 to 127. If the Primary Identifier does not indicate a valid prefix, the value is zero. Sequence Number the last heard sequence number from the node. Remaining LifeTime the time remaining before the entry is considered expired. Calculated from the LifeTime field of the Advertisement heard. Primary Identifier the primary IPv6 Unicast Address for the node, taken from the Source field of the Advertisement heard. MRU the maximum size packet that the node will receive over the link. Speed the speed of the link over which the advertisement or solicitation was heard. Higher values indicate Simpson expires in six months [Page 18] DRAFT IPv6 Discovery Formats January 1995 greater speed. The speed value (in bits per second) is related to: int( 10 * ln( speed / 100 ) ) 0 link is down 1 - 9 reserved 10 300 or less 24 1,200 96 1,544,000 T1 31 2,400 99 2,048,000 E1 38 4,800 106 4,000,000 Token Ring 42 7,200 110 6,312,000 T2 45 9,600 115 10,000,000 Ethernet 49 14,400 119 16,000,000 Token Ring 52 19,200 56 28,800 130 44,736,000 T3 59 38,400 142 155,520,000 STS-3,STM-1 63 57,600 202 622,080,000 STS-12,STM-4 64 64,000 216 2,488,320,000 STS-48,STM-16 71 128,000 73 153,600 78 256,000 Quality an indication of the signal quality received from this node. Higher values indicate greater quality. If the Quality is not used, the value is zero. Advertisement Count the number of advertisements that have been heard from the identified node. Error Count the number of errors which have been detected on the link with the identified node. This extension is included in an Advertisement message to indicate a node which has been heard. The MRU, Speed, Quality, Advertisement Count, and Error Count are primarily used for selecting among multiple paths in a wireless environment. Simpson expires in six months [Page 19] DRAFT IPv6 Discovery Formats January 1995 2.6. Prefix-Information +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extension | Length |C|R| 0 | Prefix Size | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 0 | Preference | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | ~ Identifier ~ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Extension 5 Length 18 C Contiguous. When this bit is set to 1, the routing-prefix is entirely confined to the link. When forwarding, a node MAY use the routing-prefix to determine whether a target node is on the link. R Registration. When this bit is set to 1, a node MUST use [DHCPng] to self-configure its addresses. Prefix Size the number of bits in the Identifier which define the routing-prefix width for the link. The value ranges from 0 to 127. If the Identifier does not indicate a valid prefix, the value is zero. Preference the preference level for use of this node to forward packets having a Source longest match with the Identifier. Higher values indicate greater preference. Identifier one of the IPv6 Unicast or Cluster Addresses for this interface. This extension is found in Router Advertisements. Simpson expires in six months [Page 20] DRAFT IPv6 Discovery Formats January 1995 2.7. Hop-Limit +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extension | Length | Hops | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Extension 13 Length 1 Hops the currently recommended IPv6 Hop Limit. Up-to-date values are specified in the most recent "Assigned Numbers" [RFC-1700]. Simpson expires in six months [Page 21] DRAFT IPv6 Discovery Formats January 1995 2.8. Maximum-Receive-Unit +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extension | Length | MRU | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Extension 14 Length 2 MRU the maximum size packet that the node will receive over the link. This extension MUST be included in those messages sent from an interface for which there is no dependable MTU, such as Frame-Relay or Asynchronous Transfer Mode. Simpson expires in six months [Page 22] DRAFT IPv6 Discovery Formats January 1995 2.9. Media-Access +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extension | Length | Family | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Media Address ... +-+-+-+-+-+-+-+-+-+-+-+- Extension 15 Length >= 2 Family the Address Family Number. Up-to-date values are specified in the most recent "Assigned Numbers" [RFC-1700]. Media Address the media address which is used to access this node. This field is variable in length. The Media Address is always specified in Canonical order. This extension MUST be included in those messages sent from an interface on a multi-access media. It MUST NOT be included in a message sent from a point-to-point interface, or in messages such as the Remote Redirect which pass through intermediate nodes. Simpson expires in six months [Page 23] DRAFT IPv6 Discovery Formats January 1995 2.10. Mobility-Support +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extension | Length |F| Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Extension 16 Length >= 1 F Foreign Agent bit. When this bit is set to 1, Mobile Registration through the Foreign Agent is required, even when the Mobile Node has acquired a transient Care-Of-Address. Reserved Sent as zero; ignored on reception. This extension is found in Router Advertisements. Simpson expires in six months [Page 24] DRAFT IPv6 Discovery Formats January 1995 2.11. Redirected-Header +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extension | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv6 Header(s) ... +-+-+-+-+-+-+-+-+-+-+-+- Extension 254 Length >= 64 IPv6 Header(s) variable length, 64-bit aligned. This extension is included in the Local or Remote Redirect to verify the traffic that is being redirected. Simpson expires in six months [Page 25] DRAFT IPv6 Discovery Formats January 1995 Security Considerations Whenever Ran gets them done. References [D-Send] [DHCPng] [IPv6-Address] [IPv6-ICMP] [Mobility] [RFC-1700] Acknowledgements Many thanks to Fred Goldstein, K1IO (DEC, BBN) for his pioneering work on Radio Shortest Path First (RSPF) for Amateur Packet Radio. Thanks also for suggestions and contributions from the Simple-IP Working Group. Special thanks for implementation review by Alex Conta (DEC), Chuck Desostoa (), Dan McDonald (Naval Research Laboratory), Fred Rabouw (Network Systems Netherlands), and Brad Stone (Hewlett-Packard). Author's Address Questions about this memo can also be directed to: William Allen Simpson Daydreamer Computer Systems Consulting Services 1384 Fontaine Madison Heights, Michigan 48071 Bill.Simpson@um.cc.umich.edu bsimpson@MorningStar.com Simpson expires in six months [Page 26] DRAFT IPv6 Discovery Formats January 1995 Simpson expires in six months [Page 27] DRAFT IPv6 Discovery Formats January 1995 Table of Contents 1. Additional ICMP Packets ............................... 1 1.1 Where-Are-You Solicitations ..................... 2 1.1.1 General Solicitation ............................ 3 1.1.2 Router Solicitation ............................. 5 1.2 I-Am-Here Advertisements ........................ 6 1.2.1 General Advertisement ........................... 7 1.2.2 Router Advertisement ............................ 9 1.2.3 Local Redirect .................................. 11 1.2.4 Remote Redirect ................................. 13 2. Extensions ............................................ 14 2.1 Single Pad ...................................... 15 2.2 Multiple Pads ................................... 15 2.3 Change-Identifier ............................... 16 2.4 Known-Identifier ................................ 17 2.5 Node-Heard ...................................... 18 2.6 Prefix-Information .............................. 20 2.7 Hop-Limit ....................................... 21 2.8 Maximum-Receive-Unit ............................ 22 2.9 Media-Access .................................... 23 2.10 Mobility-Support ................................ 24 2.11 Redirected-Header ............................... 25 SECURITY CONSIDERATIONS ...................................... 26 REFERENCES ................................................... 26 ACKNOWLEDGEMENTS ............................................. 26 AUTHOR'S ADDRESS ............................................. 26