Network Working Group W A Simpson Internet Draft Daydreamer expires in six months November 1994 IPv6 Neighbor Discovery -- ICMP Message Formats draft-simpson-ipv6-discov-formats-01.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 ds.internic.net (US East Coast), nic.nordu.net (Europe), ftp.isi.edu (US West Coast), or 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 November 1994 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 35 Mobile Registration Request 36 Mobile Registration Reply Simpson expires in six months [Page 1] DRAFT IPv6 Discovery Formats November 1994 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 November 1994 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::7:0). | For example, to calculate the destination value | for target A::B:C, the exclusive-or is E. The | calculated destination would be FF02::7:E. Source any IPv6 Unicast Address associated with the | sending interface. It MUST NOT contain the Unspecified Address. | Hop Limit 1 ICMP fields: Code 1 for General Solicitation. Extensions: Other-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 each Router Advertisement that has been heard, in order of preference. Simpson expires in six months [Page 3] DRAFT IPv6 Discovery Formats November 1994 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 November 1994 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 contain 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 November 1994 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 seconds remaining before the advertised | information is considered expired. The maximum time is approximately 18.2 hours. 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 November 1994 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 Source is not the Unspecified Address, the | node is not serving several clients, 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] and | [Mobility]. Source the Destination specified in 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. Other-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. | Simpson expires in six months [Page 7] DRAFT IPv6 Discovery Formats November 1994 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 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 November 1994 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 | cluster prefixes for the links are distinguished | in the Routing-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. Up-to-date | values are specified in the most recent "Assigned | Numbers" [RFC-1700]. | 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. | 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 November 1994 Change-Identifier for each of that interface's IPv6 Unicast or | Cluster Addresses which has changed from a value | previously advertised with the Routing- | Information or Other-Identifier extensions. | Included at least once, and repeated until the | original LifeTime expires. Routing-Information for each of that interface's associated IPv6 | Unicast Addresses whose Advertise flags are TRUE. * Other-Identifier for each of that node's other IPv6 Unicast or | Cluster Addresses which have not already been included through prefix subsumption. This may be | another address for the same interface, or may | identify another interface on the same node. | When a number of interfaces, such as point-to- | point interfaces, may be aggregated with the same | 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 November 1994 1.2.3. Local Redirect | The Local Redirect MUST contain at least the following values: IPv6 Header: Destination the Source specified in the packet being redirected. Source the Primary Identifier of the router. | Hop Limit 1 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. Other-Identifier for each IPv6 Unicast or Cluster Address | associated with the target node. The Metric is | always zero. When the redirect applies to an entire cluster, | the Prefix Size is set to the size of the cluster | prefix. This enables the recipient node to | determine the best next-hop without multiple | redirects for each cluster. Transit-Information one or more, when the redirect is limited to a specific Quality of Service. The Metric is | always zero. Simpson expires in six months [Page 11] DRAFT IPv6 Discovery Formats November 1994 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 November 1994 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: Change-Identifier for each of that interface's IPv6 Unicast or | Cluster Addresses which is now reached via a | Care-Of-Address. 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 [Mobility]. | Simpson expires in six months [Page 13] DRAFT IPv6 Discovery Formats November 1994 1.3. Mobile Registration Request +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Code | Checksum | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | unused | LifeTime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + Identification + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | ~ Home Agent ~ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | ~ Care-Of-Address ~ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extensions ... +-+-+-+-+-+-+-+-+-+-+-+- IPv6 Header: Destination The IPv6 Unicast Address of the Agent, when | known. Otherwise, the Mobile-Agents IPv6 Multicast | Address (FF02::11). The scope is intra-link. | Examination of the Care-Of-Address is used to deliver the datagram to the correct Agent. Source any IPv6 Unicast Address associated with the | sending interface. A Mobile Node MUST use the transient Care-Of- Address when assigned; otherwise, the Home- Address is used. ICMP fields: Type 35 | Code Bitmask of optional capabilities: 1 - retain prior registrations 2 - registering through Foreign Agent Simpson expires in six months [Page 14] DRAFT IPv6 Discovery Formats November 1994 LifeTime The seconds remaining before the registration is considered expired. A value of zero indicates a request for de-registration. A value of all ones indicates infinity. * Identification A sequence number assigned by the Mobile Node. This is used to assist in matching Requests with Replies. A Network Time Protocol [RFC-1305] formatted value is preferred. The low-order 32 bits of the NTP format represent fractional seconds, and those bits which are not available from a time source SHOULD be generated from a good source of randomness. A battery-backed clock is the usual source of this value. In more robust implementations, Global Positioning System or authenticated NTP values MAY be used. The elapsed time since system startup or another such monotonically increasing counter MAY be used, but is considered less secure, as it could repeat each time the machine is restarted, or when a poor source of randomness is used for the low-order bits. See | [Eastlake] for a discussion of sources of | randomness. It is possible to use an entirely random "nonce" in this field, or to generate nonces from previous registration exchanges. We have not standardized this procedure because of intellectual property concerns. It is also incompatible with the expected venue of the protocol, and presents difficulties with interoperability and security validation. The value MUST NOT be the same as an immediately preceeding request, and SHOULD NOT repeat during the lifetime of the Mobility Security Association between the Mobile Node and the Home Agent. | Home Agent The IPv6 Unicast Address of a Home Agent. | Care-Of-Address The IPv6 Unicast Address for the decapsulation | end of a tunnel. Extensions: Simpson expires in six months [Page 15] DRAFT IPv6 Discovery Formats November 1994 Other-Identifier the Home-Address of the Mobile Node. The Metric | is always zero. | When the request applies to an entire cluster, | the Prefix Size is set to the size of the cluster | prefix. | Maximum-Receive-Unit | for interfaces which do not have a fixed hardware | MTU. | Media-Access for interfaces which are not point-to-point | links. Mobile-Home Authentication Immediately follows all non-authentication * extensions. When forwarded by a Foreign Agent, all extensions are copied without | modification. Those extensions which are specific to the Foreign | Agent are ignored by the Home Agent. | The use of the Registration Request is described in [Mobility]. Simpson expires in six months [Page 16] DRAFT IPv6 Discovery Formats November 1994 1.4. Mobile Registration Reply +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Code | Checksum | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | unused | LifeTime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + Identification + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extensions ... +-+-+-+-+-+-+-+-+-+-+-+- IPv6 Header: The Source and Destination of the Request message are swapped for the Reply message. Note that the Source of the original Mobile Registration Request must be saved in order for a Foreign Agent to return the reply to the correct Mobile Node. ICMP fields: Type 36 | Code One of the following codes: 0 service will be provided. denied by Foreign Agent, 16 reason unspecified. 17 administratively prohibited. 18 insufficient resources. 19 Mobile Node failed authentication. 20 Home Agent failed authentication. 21 Request LifeTime too long. denied by Home Agent, 32 reason unspecified. 33 administratively prohibited. 34 insufficient resources. 35 Mobile Node failed authentication. 36 Foreign Agent failed authentication. Up-to-date values of the Code field are specified | in the most recent "Assigned Numbers" [RFC-1700]. Simpson expires in six months [Page 17] DRAFT IPv6 Discovery Formats November 1994 LifeTime The seconds remaining before the registration is considered expired. A value of zero confirms a request for de-registration. A value of all ones indicates infinity. | The value MAY be changed by the Home Agent. Identification Copied from the Request message. Extensions: Other-Identifier the Home-Address of the Mobile Node. The Metric | is always zero. | When the reply applies to an entire cluster, the | Prefix Size is set to the size of the cluster | prefix. Mobile-Home Authentication Immediately follows all non-authentication * extensions. Note that the Care-Of-Address and Home Agent are not present in the message. This provides a separate calculation value for mutual authentication. When forwarded by a Foreign Agent, all extensions are copied without | modification. Those extensions which are specific to the Foreign | Agent are ignored by the Home Agent. | The use of the Registration Reply is described in [Mobility]. Simpson expires in six months [Page 18] DRAFT IPv6 Discovery Formats November 1994 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 Other-Identifier | 4 Node-Heard | 5 Routing-Information 6 Service-Information (reserved) | 7 Transit-Information 13 Hop-Limit | 14 Maximum-Receive-Unit 15 Media-Access 16 Mobility-Support | 17 Home-Address (obsolete) 32 Mobile-Home Authentication 64 Minimal Encapsulation (obsolete) | 65 GRE Encapsulation 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 Simpson expires in six months [Page 19] DRAFT IPv6 Discovery Formats November 1994 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. 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 20] DRAFT IPv6 Discovery Formats November 1994 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 cluster prefix width for the link. The value ranges from 0 to 126. | If the Identifier does not indicate a valid prefix, | the value is zero. | Non-routers MUST set this field to zero. | Identifier an IPv6 Unicast or Cluster Address. For Router Advertisements, gives advance indication that an address | or prefix will no longer be routable. Applications SHOULD cease to | accept new connections with the old value. Existing connections | SHOULD issue a Remote Redirect. For Remote Redirects, provides a Care-Of-Address to a Correspondent. | Simpson expires in six months [Page 21] DRAFT IPv6 Discovery Formats November 1994 2.4. Other-Identifier +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extension | Length | 0 | Prefix Size | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Metric | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | ~ Identifier ~ | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Extension 3 Length 22 | Prefix Size the number of bits in the Identifier which define | the cluster prefix width for the link. The value ranges from 0 to 126. If the Identifier does not indicate a valid prefix, | the value is zero. Non-routers MUST set this field to zero. Metric the preference level for use of this node to forward | packets to the Identifier. Lower values indicate greater preference. Non-routers MUST set this field to zero. | Identifier an IPv6 Unicast or Cluster Address. For usage, see the specific message description. | Simpson expires in six months [Page 22] DRAFT IPv6 Discovery Formats November 1994 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 cluster prefix width for the link. The value ranges from 0 to 126. 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 seconds remaining before the entry is considered | expired. | Primary Identifier | the primary IPv6 Unicast or Cluster 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. Simpson expires in six months [Page 23] DRAFT IPv6 Discovery Formats November 1994 Speed the speed of the link over which the advertisement | or solicitation was heard. Higher values indicate greater speed. The speed value is related to int( 10 * ln( speed / 100 ) ) in bits per second. 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. 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 24] DRAFT IPv6 Discovery Formats November 1994 2.6. Routing-Information +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extension | Length | Preference |C| Prefix Size | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | * ~ Identifier ~ | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Extension 5 Length 18 | 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. C Cluster bit. When this bit is set to 1, the IPv6 Cluster is entirely confined to the link. When forwarding, a node MAY use the prefix to determine whether a target node is on the link. * Prefix Size the number of bits in the Identifier which define | the cluster prefix width for the link. The value ranges from 0 to 126. If the Identifier does not indicate a valid prefix, | the value is zero. | 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 25] DRAFT IPv6 Discovery Formats November 1994 2.7. Transit-Information | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extension | Length | 0 | QoS | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Metric | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Extension 7 Length 6 QoS a quality of service for which transit will be | accepted. Metric the preference level for use of this link to forward | packets of the indicated Quality of Service. Lower values indicate greater preference. For redirects, this indicates that the redirect is limited to only | the particular service. If this extension is not included, the redirect includes all services. Simpson expires in six months [Page 26] DRAFT IPv6 Discovery Formats November 1994 2.8. 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 27] DRAFT IPv6 Discovery Formats November 1994 2.9. 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. It MUST NOT be included in messages such as the Remote Redirect which pass through intermediate nodes. Simpson expires in six months [Page 28] DRAFT IPv6 Discovery Formats November 1994 2.10. 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 29] DRAFT IPv6 Discovery Formats November 1994 2.11. 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 30] DRAFT IPv6 Discovery Formats November 1994 2.12. Mobile-Home Authentication Extension +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | Extension | Length | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Authenticator ... | +-+-+-+-+-+-+-+-+-+-+-+- | Extension 32 Length The number of data bytes in the Extension (16 when MD5 is used). Authenticator variable length (128 bits for MD5), 64-bit aligned. | A hash value taken over a stream of bytes consisting of the shared secret, followed by (concatenated with) the fields in the Mobile Registration message beginning with the Type field, including all prior extensions, and the Type and Length of this extension, but not including the Authenticator field itself. This extension is found in all Mobile Registration Requests and | Replies. The value differs depending on the direction the message is sent, since the Mobile Registration Request and Reply have different fields. Simpson expires in six months [Page 31] DRAFT IPv6 Discovery Formats November 1994 2.13. GRE Encapsulation Extension | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extension | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Extension 65 | Length 0 | This extension is found in Router Advertisements and Mobile | Registration Requests. GRE is described in [RFC-1701]. | Simpson expires in six months [Page 32] DRAFT IPv6 Discovery Formats November 1994 2.14. 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 33] DRAFT IPv6 Discovery Formats November 1994 Security Considerations Whenever Ran gets them done. | References [D-Send] | [Eastlake] | [IPv6-Address] [IPv6-ICMP] | [Mobility] [RFC-1305] | [RFC-1700] | [RFC-1701] 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 and the Mobile-IP Working Group. | Special thanks for implementation review by Alex Conta (DEC), Dan | McDonald (Naval Research Laboratory), and Fred Rabouw (Network | Systems Netherlands). Author's Address Questions about this memo can also be directed to: William Allen Simpson Daydreamer Computer Systems Consulting Services 1384 Fontaine Simpson expires in six months [Page 34] DRAFT IPv6 Discovery Formats November 1994 Madison Heights, Michigan 48071 Bill.Simpson@um.cc.umich.edu bsimpson@MorningStar.com Simpson expires in six months [Page 35]