Network Working Group W A Simpson Internet Draft Daydreamer expires in six months March 1994 SIPP Neighbor Discovery -- ICMP Message Formats draft-ietf-sipp-discovery-formats-00.txt Status of this Memo This document is a submission to the SIPP Working Group of the Internet Engineering Task Force (IETF). Comments should be submitted to the sipp@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. Internet Drafts 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.'' Please check the 1id-abstracts.txt listing contained in the internet-drafts Shadow Directories on nic.ddn.mil, ds.internic.net, venera.isi.edu, nic.nordu.net, or munnari.oz.au to learn the current status of any Internet Draft. Abstract This document specifies ICMP messages for the identification and location of adjacent SIPP nodes. Simpson expires in six months [Page i] DRAFT SIPP Discovery Formats March 1994 1. Additional ICMP Packets The Packet format and basic facilities are already defined for ICMP as modified for SIPP [1]. Up-to-date values of the ICMP Type field are specified in the most recent "Assigned Numbers" RFC [2]. This document concerns the following values: Where-Are-You I-Am-Here Simpson expires in six months [Page 1] DRAFT SIPP Discovery Formats March 1994 1.1. Where-Are-You 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Code | Checksum | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extensions ... +-+-+-+-+-+-+-+-+-+-+-+- Type Code 8 bits. Up-to-date values are specified in the most recent "Assigned Numbers" RFC [2]. Current values are assigned as follows: 0 RESERVED 1 General Solicitation 2 Router Solicitation 3 Service Solicitation Checksum The ICMP Checksum. Extensions This field is variable in length and contains zero or more Extensions. These Extensions are described in a later section. 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. 1.1.1. General Solicitation The General Solicitation contains the following values: - In the Destination Address field of the SIPP header: an identifying-address of the target. - In the Source Address field of the SIPP header: any identifying- address associated with the sending node. It MAY contain zero, when the node has not yet determined an identifying-address. Simpson expires in six months [Page 2] DRAFT SIPP Discovery Formats March 1994 - In the Routing-Header (when used), a cluster-address which completes a local address-sequence. - In the Code field of the ICMP header: 1 for General Solicitation. - For interfaces which are not point-to-point links, the Media- Access extension. - For each router advertisement that has been heard, the System- Heard extension. 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. 1.1.2. Router Solicitation The Router Solicitation contains the following values: - In the Destination Address field of the SIPP header: the all- routers multicast, with the scope set to intra-link. - In the Source Address field of the SIPP header: any identifying- address associated with the sending node. It MAY contain zero, when the node has not yet determined an identifying-address. - In the Routing-Header (when used), a cluster-address which completes a local address-sequence. - In the Code field of the ICMP header: 2 for Router Solicitation. - For interfaces which are not point-to-point links, the Media- Access extension. - For each of that node's identifying-addresses other than the primary identifying-address, the Other-Identifier extension, with the prefix size set to zero. In the unlikely event that not all extensions fit in a single solicitation, as constrained by the MTU of the link, multiple solicitations are sent, with each except the last containing as many extensions as can fit. Simpson expires in six months [Page 3] DRAFT SIPP Discovery Formats March 1994 1.1.3. Service Solicitation The Service Solicitation contains the following values: - In the Destination Address field of the SIPP header: the multicast group associated with the service, with the scope set to intra- link. - In the Source Address field of the SIPP header: any identifying- address associated with the sending node. It MAY contain zero, when the node has not yet determined an identifying-address. - In the Routing-Header (when used), a cluster-address which completes a local address-sequence. - In the Code field of the ICMP header: 3 for Service Solicitation. - For interfaces which are not point-to-point links, the Media- Access extension. 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. Simpson expires in six months [Page 4] DRAFT SIPP Discovery Formats March 1994 1.2. I-Am-Here 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Code | Checksum | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence Number | LifeTime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + Node Identifying-Address + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extensions ... +-+-+-+-+-+-+-+-+-+-+-+- Type Code 8 bits. Up-to-date values are specified in the most recent "Assigned Numbers" RFC [2]. Current values are assigned as follows: 0 RESERVED 1 General Advertisement 2 Router Advertisement 3 Service Advertisement 4 Local Redirect 5 Remote Redirect Checksum The ICMP Checksum. Sequence Number 16 bits. Contains the number of I-Am-Here messages sent since the node was initialized. This number MUST include this advertisement. LifeTime 16 bits. Indicates the seconds remaining before the entry is considered expired. Node Identifying-Address 64 bits. Contains the primary identifying-address for this node. Extensions This field is variable in length and contains zero or more Extensions. These Extensions are described in a later section. Simpson expires in six months [Page 5] DRAFT SIPP Discovery Formats March 1994 1.2.1. General Advertisement The General Advertisement contains the following values: - In the Destination Address field of the SIPP header: when responding to general solicitations, the Source Address specified in the solicitation. For periodic mobile advertisements, the all-routers multicast, with the scope set to intra-link. - In the Source Address field of the SIPP header: when responding to general solicitations, the identifying-address specified in the solicitation. For periodic mobile advertisements, any identifying-address associated with the node. - In the Code field of the ICMP header: 1 for General Advertisement. - In the Node Identifying-Address field of the ICMP header: the primary identifying-address associated with that node. - In the Lifetime field: the interface's configured AdvertisementLifetime. - For each of that node's identifying-addresses other than the primary identifying-address, the Other-Identifier extension, with the prefix size set to zero. - For each service advertisement that is offered, the Service- Information extension. - For each router advertisement that has been heard, the System- Heard extension. - For interfaces which are not point-to-point links, the Media- Access extension. 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 except the last containing as many extensions as can fit. 1.2.2. Router Advertisement The Router Advertisement contains the following values: - In the Destination Address field of the SIPP header: the all-nodes multicast, with the scope set to intra-link. Simpson expires in six months [Page 6] DRAFT SIPP Discovery Formats March 1994 - In the Source Address field of the SIPP header: the primary identifying-address of the node. The same identifying-address is used for all interfaces. - In the Code field of the ICMP header: 2 for Router Advertisement. - In the Node Identifying-Address field of the ICMP header: the primary identifying-address associated with that node. - In the Lifetime field: the interface's configured AdvertisementLifetime. - For each of that interface's associated identifying-addresses whose Advertise flags are TRUE, the Routing-Information extension. - For each of that interface's recently changed identifying- addresses, the Change-Identifier extension. - For each of that node's other identifying-addresses which have not already been included through prefix subsumption, the Other- Identifier extension. - For each service that is offered, the Service-Information extension. - For each router advertisement that has been heard, the System- Heard extension. - For interfaces which are not point-to-point links, the Media- Access extension. 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 except the last containing as many extensions as can fit. Simpson expires in six months [Page 7] DRAFT SIPP Discovery Formats March 1994 1.2.3. Service Advertisement The Service Advertisement contains the following values: - In the Destination Address field of the SIPP header: when responding to service solicitations, the all-nodes multicast. For periodic mobile advertisements, the all-routers multicast. with the scope set to intra-link. - In the Source Address field of the SIPP header: when responding to service solicitations, the identifying-address specified in the solicitation. For periodic mobile advertisements, any identifying-address associated with the node. - In the Code field of the ICMP header: 3 for Service Advertisement. - In the Node Identifying-Address field of the ICMP header: the primary identifying-address associated with that node. - In the Lifetime field: the interface's configured AdvertisementLifetime. - For each of that node's identifying-addresses other than the primary identifying-address, the Other-Identifier extension, with the prefix size set to zero. - For each service advertisement that is offered, the Service- Information extension. - For each router advertisement that has been heard, the System- Heard extension. - For interfaces which are not point-to-point links, the Media- Access extension. 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 except the last containing as many extensions as can fit. 1.2.4. Local Redirect The Local Redirect contains the following values: - In the Destination Address field of the SIPP header: the Source Address specified in the packet being redirected. Simpson expires in six months [Page 8] DRAFT SIPP Discovery Formats March 1994 - In the Source Address field of the SIPP header: the primary identifying-address associated with the sending node. - In the Code field of the ICMP header: 4 for Local Redirect. - In the Node Identifying-Address field of the ICMP header: the primary identifying-address associated with the target node. - In the Sequence field: the last Sequence from the target node Advertisement. - In the Lifetime field: the remaining Lifetime from the target node Advertisement. - When the redirect applies to an entire cluster, one or more Other-Identifier extensions, with the metric set to zero. - When the redirect is limited to a specific Quality of Service, one or more Transit-Information extensions, with the metric set to zero. - For interfaces which are not point-to-point links, the Media- Access extension of the target node. - The Redirected-Header extension. 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. 1.2.5. Remote Redirect The Remote Redirect contains the following values: - In the Destination Address field of the SIPP header: the Source Address specified in the packet being redirected. - In the Source Address field of the SIPP header: the primary identifying-address associated with the sending node. - In the Code field of the ICMP header: 5 for Remote Redirect. - In the Node Identifying-Address field of the ICMP header: the primary identifying-address associated with the target node. - In the Sequence field: the last Sequence from the target node Simpson expires in six months [Page 9] DRAFT SIPP Discovery Formats March 1994 Advertisement. - In the Lifetime field: the remaining Lifetime from the target node Advertisement. - When the SIPP Destination Address of the redirected packet is changing, the Change-Identifier extension, with the Prefix Size set to zero. - The Redirected-Header extension. 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. Simpson expires in six months [Page 10] DRAFT SIPP Discovery Formats March 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 SIPP packet. 0 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- | Type | Length | Data ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- Type 8 bits. Up-to-date values are specified in the most recent "Assigned Numbers" RFC [2]. Current values are assigned as follows: 1 Media-Access 2 Change-Identifier 3 Other-Identifier 4 System-Heard 5 Routing-Information 6 Service-Information 7 Transit-Information 8 Redirected-Header Length 8 bits. Indicates the length of the Data field which has been used. The Length does not include the Type and Length octets. value total space used 0 through 2 4 3 through 6 8 7 through 10 12 Data This field is zero or more octets and contains the value or other information for this Extension. The format and length of the Data field is determined by the Type and Length fields. Each Extension begins on an octet boundary which is an integral multiple of 32 bits. Any unused portion of the packet between Simpson expires in six months [Page 11] DRAFT SIPP Discovery Formats March 1994 Extensions is padded with zeros. The final Extension in a packet does not need padding. There is no explicit "pad" or "end" extension. 2.1. Media-Access 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | Media Type | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MAC Address ... +-+-+-+-+-+-+-+-+-+-+-+- Type 1 Length >= 4 Media Type 16 bits. The value of this field is the same as the Hardware Type used in ARP. Up-to-date values are specified in the most recent "Assigned Numbers" RFC [2]. MAC Address This field is variable in length and contains the media address which is used to access this node. The MAC Address is always specified in Canonical order. The Media-Access 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 12] DRAFT SIPP Discovery Formats March 1994 2.2. Change-Identifier 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | |Prefix Size| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + Old Identifying-Address + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + New Identifying-Address + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type 2 Length 22 Prefix Size 6 bits. Indicates the number of bits in both Identifying-Addresses which define the prefix mask for the link. The value ranges from 0 to 62. Old Identifying-Address 64 bits. Depending on the Prefix Size, it may indicate a cluster, or a single identifying-address. New Identifying-Address 64 bits. Depending on the Prefix Size, it may indicate a cluster, or a single identifying-address. This extension is sent only by routers. For advertisements, this allows changing a prefix for every node on a router's interface. For redirects, this allows changing a single target identifying- address. Simpson expires in six months [Page 13] DRAFT SIPP Discovery Formats March 1994 2.3. Other-Identifier 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | |Prefix Size| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Metric | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + Identifying-Address + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type 3 Length 14 Prefix Size 6 bits. Indicates the number of bits in the Identifying-Address which define the prefix mask for the link. The value ranges from 0 to 62. If the Identifying-Address does not indicate a valid prefix, the value is zero. Non-routers MUST set this field to zero. Metric 32 bits. Indicates the preference level for use of this node to forward packets to the Identifying- Address. Lower values indicate greater preference. Non-routers MUST set this field to zero. Identifying-Address 64 bits. Contains one of the identifying-addresses for this node. This may be another identifying- address for the same interface that sent the message, or may identify another interface on the same node which sent the message. This supports multiple identifying-addresses per interface, as well as multi-homed nodes. When a number of interfaces, such as point-to-point interfaces, may be aggregated with the same prefix, only one extension need be included. Simpson expires in six months [Page 14] DRAFT SIPP Discovery Formats March 1994 For advertisements, this enables the recipient node to determine the best next-hop without sending a Where-Are-You solicitation when the next-hop is on another interface attached to the same advertising node. For redirects, this enables the recipient node to determine the best next-hop without multiple redirects for each cluster. 2.4. System-Heard 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | |D|B|Prefix Size| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sequence Number | Remaining LifeTime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + Node Identifying-Address + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MRU | | Speed | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Quality | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Advertisement Count | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Error Count | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type 4 Length 30 Designated Bit Indicates that the Node Identifying-Address is the Designated Router. Backup Bit Indicates that the Node Identifying-Address is the Backup Designated Router. Prefix Size 6 bits. Indicates the number of bits in the Node Identifying-Address which define the prefix mask for the link. The value ranges from 0 to 62. If the Node Identifying-Address does not indicate a Simpson expires in six months [Page 15] DRAFT SIPP Discovery Formats March 1994 valid prefix, the value is zero. Non-routers MUST set this field to zero. Sequence Number 16 bits. Contains the last heard sequence number from the node. Remaining LifeTime 16 bits. Indicates the seconds remaining before the entry is considered expired. Node Identifying-Address 64 bits. Contains the primary identifying-address for the node, taken from the Source Address field of the advertisement heard. MRU 16 bits. Indicates the maximum size packet that the node will receive over the link. Speed 8 bits. Indicates 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 32 bits. Contains an indication of the signal quality received from this node. Higher values indicate greater quality. Simpson expires in six months [Page 16] DRAFT SIPP Discovery Formats March 1994 Advertisement Count 32 bits. Indicates the number of advertisements that have been heard from the identified node. Error Count 32 bits. Indicates the number of errors which have been detected on the link with the identified node. This extension is included in the I-Am-Here message to indicate a node which has been heard. 2.5. Routing-Information 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | |D|B|Prefix Size| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MRU | Preference | Priority | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + Identifying-Address + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type 5 Length 14 Designated Bit Indicates that the Node Identifying-Address is the Designated Router. Backup Bit Indicates that the Node Identifying-Address is the Backup Designated Router. Prefix Size 6 bits. Indicates the number of bits in the Identifying-Address which define the prefix mask for the link. The value ranges from 0 to 62. If the Identifying-Address does not indicate a valid prefix, the value is zero. MRU 16 bits. Indicates the maximum size packet that the node will receive over the link. Preference 8 bits. Indicates the preference level for use of Simpson expires in six months [Page 17] DRAFT SIPP Discovery Formats March 1994 this node to forward packets to the Identifying- Address. Higher values indicate greater preference. Priority 8 bits. Indicates the priority for election to Designated Backup. A value of zero indicates that the node is not eligible. Identifying-Address 64 bits. Contains one of the identifying-addresses for this interface. This extension is sent only by Routers. When more than one of these extensions is present, the Designated and Backup bits, MRU and Priority fields MUST be the same in each copy. 2.6. Service-Information 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | Service | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Data ... +-+-+-+-+-+-+-+-+-+-+-+- Type 6 Length >= 2 Service 16 bits. The value of this field is usually the same as the well-known port number. Up-to-date values are specified in the most recent "Assigned Numbers" RFC [2]. Data This field is variable in length and contains information specific to the service. For example, it could contain a string with the description of the service. The format of the Data field is entirely service dependent, and is always treated as a binary value. Simpson expires in six months [Page 18] DRAFT SIPP Discovery Formats March 1994 2.7. Redirected-Header 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SIPP Header ... +-+-+-+-+-+-+-+-+-+-+-+- Type 8 Length 54 SIPP Header 48 octets. This extension is included in the Local or Remote Redirect to verify the traffic that is being redirected. Simpson expires in six months [Page 19] DRAFT SIPP Discovery Formats March 1994 Security Considerations References [1] [2] Acknowledgments Simpson expires in six months [Page 20] DRAFT SIPP Discovery Formats March 1994 Chair's Address The working group can be contacted via the current chairs: Stephen Deering Paul Francis 3333 Coyote Hill Road 445 South St. 2L-281 Palo Alto, CA 94304 Morristown, NJ 07960 415-812-4839 201-829-4484 Deering@PARC.Xerox.com francis@thumper.bellcore.com Robert M Hinden 2550 Garcia Avenue Mountain View, CA 94043-1100 415-336-2082 hinden@Eng.Sun.com 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 21] DRAFT SIPP Discovery Formats March 1994 Table of Contents 1. Additional ICMP Packets ............................... 1 1.1 Where-Are-You ................................... 2 1.1.1 General Solicitation ............................ 2 1.1.2 Router Solicitation ............................. 3 1.1.3 Service Solicitation ............................ 4 1.2 I-Am-Here ....................................... 5 1.2.1 General Advertisement ........................... 6 1.2.2 Router Advertisement ............................ 6 1.2.3 Service Advertisement ........................... 8 1.2.4 Local Redirect .................................. 8 1.2.5 Remote Redirect ................................. 9 2. Extensions ............................................ 11 2.1 Media-Access .................................... 12 2.2 Change-Identifier ............................... 13 2.3 Other-Identifier ................................ 14 2.4 System-Heard .................................... 15 2.5 Routing-Information ............................. 17 2.6 Service-Information ............................. 18 2.7 Redirected-Header ............................... 19 SECURITY CONSIDERATIONS ...................................... 20 REFERENCES ................................................... 20 ACKNOWLEDGEMENTS ............................................. 20 CHAIR'S ADDRESS .............................................. 21 AUTHOR'S ADDRESS ............................................. 21