Network Working Group Danny Cohen Internet Draft Myricom Expires in six months Craig Lund Mercury Computers Tony Skjellum Mississippi State University Thom McMahon Mississippi State University Robert George Mississippi State University October 1997 Part-1 of The Router-to-Router (RRP) PacketWay Protocol for High-Performance Interconnection of Computer Clusters Status of this Memo 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 inappropriate to use Internet- Drafts as reference material or to cite them other than as "work in progress." To view the entire list of current Internet-Drafts, please check the "1id-abstracts.txt" listing contained in the Internet-Drafts Shadow Directories on ftp.is.co.za (Africa), ftp.nordu.net (Europe), munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or ftp.isi.edu (US West Coast). Table of Content: 1. Introduction....................................................2 2. A note about the PktWay documents...............................5 3. Notations.......................................................5 4. Implementation Levels of RRP....................................6 5. Use of RRP Messages by Levels...................................7 6. Node Attributes.................................................8 7. RRP Messages....................................................9 8. RRP Message Structure..........................................10 9. RRP Record Format..............................................12 10. Examples for RRP Message.......................................16 11. Appendix-A: Example of the use of RRP..........................21 12. Appendix-B: Glossary...........................................26 13. Appendix-C: Acronyms and Abbreviations.........................27 14. Appendix-D: PktWay at a Glance ("cheat-sheet").................29 15. Security Considerations........................................30 16. Editor's Address...............................................30 Cohen et al [Page 1] Internet-Draft PktWay Router-to-Router Protocol October 1997 1. Introduction The PktWay protocol is introduced in the "The End-to-End (EEP) PacketWay Protocol for High-Performance Interconnection of Computer Clusters". This document defines the basic part (Part 1) of the Router-to-Router protocol (RRP) of PacketWay. The shorter "PktWay" is used for "PacketWay". More information about the PktWay activity is available from the PktWay web site {http://www.erc.msstate.edu/PktWay}. The architecture of PktWay is very similar to the IP family (indeed, it heavily borrows from IP), with emphasis on performance not generality and scaleability as was selected for IP. Like IP, PktWay is based on an End-to-End protocol (EEP) that assumes that if an address (or equivalent specification of the destination) is placed in the appropriate field in the packet header, then the packet will arrive to that destination. Neither IP nor EEP specify how this happens. Routers are responsible to transfer packets from their source networks to their destination networks (possibly via other networks). The communication among the routers (such the entire family of the GGPs [Gateway/Gateway Protocols] as they were originally called) is NOT a part of IP (as defined originally in RFC-791 and MIL-STD-1777). Similarly, nor is it a part of EEP. Like the IP family, PktWay defines separately its Router-to-Router Protocol (RRP), in a device- and network-independent manner. However, the model of routers in PktWay is slightly different from the original model in the IP family. IP routers (or gateways as they were called then) are monolithic devices, provided by their vendors. Each IP-router is a bona-fide host on two (or more) networks. The communication among these intra-router hosts is an internal "private" issue, handled by each vendor as it sees fit, not subject to published standards. In the PktWay model a router is (like in the IP model) a set of cooperating bona-fide hosts on two (or more) networks. These hosts, each being a full-fledged host on its SAN are called "half-routers" (HRs). However, the intra-router communication among these hosts is a "public" issue, handled according to the RRP which defines only the Network-level [Level-2], and not the Physical-level [Level-1], of this communication. Cohen et al [Page 2] Internet-Draft PktWay Router-to-Router Protocol October 1997 PktWay does not define the nature of this interconnection. However, we believe the PCI Local Bus de facto standard and internal SANs will become a very popular link for short distances, and serial fiber for long ones. Such an HR may be implemented by separate "boxes" with a long inter-SAN communication link between them, or inside a single "multi-homed" box that has an interface to each SAN, with these interfaces being interconnected via a bus or an internal-SAN. RRP defines (via message structure and behavior) the interactions between HRs, and between HRs and nodes. RRP does not define the lower level (PHY) protocols that deliver its messages (over links, or between processes). In particular, RRP does not define the inter-SAN interconnection links between the HRs -- these are left for mutual agreements among the implementors of each HR. RRP defines (like IP's GGP) the router/router and the intra-SAN node/router communication of PktWay. Nodes usually do not communicate explicitly with HRs on other SANs. The HRs within a single router are called "twins". A router that is connected to N SANs has N HRs, each being a twin of all the other ones. ("Half" and "twin" do not imply that there are only two.) All the HRs that are connected to the same SAN (being parts of different routers) are called "buddies". An HR communicates with nodes on its own SAN, with its twins that are on other SANs, and with its buddies that are on its SAN. RRP defines all these communications. Nodes may ask routers to forward messages to destinations specified either by L2-routes or by L3-addresses. Routers may provide L2-routes to nodes upon their own initiative, or upon request by the nodes. A node may ask (by [HRTO] messages) any router on its SAN, which router on their SAN is the best to use for a given destination (the nodes will typically ask their default routers for this information). In response, the router redirects (using [RDRC] messages) the node to the best router for the specified destination. At any time routers may "redirect" the node by providing more appropriate local routers for certain destinations, either upon request by the node, or upon the initiative of the router (e.g., to circumvent a fault). Cohen et al [Page 3] Internet-Draft PktWay Router-to-Router Protocol October 1997 Nodes may ask (by [TELL]) routers for information about other nodes, typically using PktWay-address, name, or capabilities to specify those nodes. In response, routers may provide (by [INFO]) a slew of data about the specified node(s), including physical-address, and optionally logical-addresses, name, and capabilities, if any. PktWay nodes may use a SRVLOC to locate required resources. It is assumed that each HR has a Routing Table (RT) for its own SAN (aka Local Routing Table, LRT), with (at least) the addresses of all the nodes and the source routes to each of them from the HR (and possibly also names and capabilities for each node). This information could be dynamic or static, even manually configured. The HRs may (or may not) perform dynamic mapping of their SANs. It is also assumed that each node, on each SAN/LAN, knows the SR to at least one HR on its SAN/LAN, and that it has a default-HR defined. In order to be able to provide the nodes with such information, each HR must collect this information about all the nodes in its own SAN. This may be performed dynamically, or statically, in either an automated or manual manner. RRP does not sepcify how this information is gathered. Each HR gives its Local Routing Table to all his twins. HRs always share with twins information received from buddies, and with buddies information received from twins. This yields the global mapping of the PktWay. All the various RRP messages are composed of a small set of common records. This document defines the messages, their structure, their common records, and their format. Several examples are used to illustrate the operation of the RRP. RRP specifies a series of options that allow system designers to deploy PktWay nodes and routers of varying levels of capabilities ("intelligence"). There are four implementation levels of PktWay, indicated by a letter code. The higher the letter code ("A" = lowest), the more interoperability and adaptability result. System designers may choose the level of implementation to best suit their needs. Cohen et al [Page 4] Internet-Draft PktWay Router-to-Router Protocol October 1997 2. A note about the PacketWay Documents The PacketWay protocol is defined by a series of documents: * EEP (End-to-End Protocol) * RRP-1 (basic Router-to-Router Protocol) * RRP-2 (dynamic inter-SAN routing) * PktWay enumerations Each of these documents should include the same "PacketWay at a Glance (Cheat-Sheet)", this note, and the Notations page. They should include also (as appendices) a copy of the PacketWay glossary of terms and its acronyms and abbreviations list. The EEP and the RRP documents will be published first as Internet-Drafts and later as Proposed-Standards, Draft-Standards, and Standards. The Enumeration Document will be first published as an "Informational-RFC" and later will be maintained by IANA. The enumeration document may be attached to the EEP/RRP documents, as a matter of convenience. The enumeration is NOT a part of the PktWay standard, just as RFC0739 (the original "Assigned Numbers" RFC) is not a part of RFC0791, that defines IP. Similarly, the EEP-document has "Appendix-A: A Recommendation for PktWay Address Assignment" which is a recommendation only and NOT a part of the PktWay standard, just as IP-address-assignment is not a part of RFC0791, that defines IP. The appendices are brought for clearance and convenience. They are not a part of the PktWay specification. Information about the PktWay activity may be found in the URL: http://www.erc.msstate.edu/PktWay/ 3. Notations The shorter "PktWay" is used for "PacketWay". 8B means "8-byte" (64 bits). 0x indicates hexadecimal values, e.g., 0x0100 is 2^8=256(decimal). 0b indicates binary values, e.g., 0b0100 is 4(decimal). Cohen et al [Page 5] Internet-Draft PktWay Router-to-Router Protocol October 1997 xxxx indicate a field that is discarded without any checking (e.g., padding). [fff] indicates that fff is an optional field, when appropriate. [exp] in equations, is the integral part, rounded down, of `exp`. e.g., [23/8]=2. All length fields do not include themselves, and therefore may be 0. Lengths are specified either (a) by byte count, implying that some padding bytes may follow to fill 8B-words, or (b) by 8B-word count and PL, the number of trailing padding bytes (with PL between 0 and 7). 4. The Four Implementation Levels of RRP Level-A: Hosts have pre-wired (static) native routing. It's an L2 ("MAC"-based) operation. HRs do not provide any info to nodes, nor to other HRs. No RRP-messages are used in this level. Level-B: L2 (MAC based) or L3 forwarding (planner transfers, IP-like operation). Nodes may ask HRs for L2 routing and for the HR to use for given destinations. In this level the following RRP-messages are used: [GVL2], [L2SR], [HRTO], and [RDRC]. In addition the [WRU]? and [INFO] messages may be used, too. Level-C: Node discovery (with static or dynamic routing). In this level nodes may ask HRs for information about other nodes, including their capabilities. In this level the [TELL] and the [INFO] RRP-messages are used in addition to those of Level-B. Level-D: In this level there is a dynamic exchange of routing tables among the HRs. This create globals mapping of the PktWay, and allows for dynamic circumvention of faults. The [GVRT] and the [RTBL] RRP-messages are used for this exchange among the HRs. Level-D applies only to routers, not to nodes. Level-B is an extension of Level-A (i.e., Level-B exists only with Level-A). Level-C and Level-D are independent extensions of Level-B. Level-B is the basic level of RRP. This document, RRP Part-1 (aka RRP1), defines the RRP messages used for Level-B and Level-C. Level-D is defined in RRP Part-2 (aka RRP2). Cohen et al [Page 6] Internet-Draft PktWay Router-to-Router Protocol October 1997 In L2 operation under Level-B , when a source node, SN, needs to send a message to a destination node, DN, it first uses a [GVL2] message to ask any of the HRs on the SN's SAN for a source route (SR) from HR to DN. That HR would either (1) use an [L2SR] message to provide such an SR, or (2) use an [RDRC] message to "re-direct", by suggesting to SN to use the specified HR (which is also on SN's SAN), or (3) use an error message to report no knowledge of DN (using the UNK error message). SN may ask more than one HR for SRs to the same DN and use any algorithm to choose which of these SRs to use. RRP does not specify whether (and how) to cache SRs. In L3 operation, when a source node, SN, needs to send a message to a destination node, DN, it sends that message to any of the HRs on its SAN, using L2, expecting L3-forwarding to DN, using DN's PktWay address. That HR would either (1) forward the message toward DN, and possibly return to SN a "re-direct" message, suggesting to use, in the future, another HR on SN's SAN for DN, or (2) report no knowledge of DN (using the UNK error message). Under Level-C nodes may be located by PktWay-addresses, names, or capabilities, but only addresses may be used for routing. 5. Use of RRP Messages by Levels Level-A: no RRP messages used Level-B: nodes send: HRTO, GVL2, WRU?, INFO nodes receive: RDRC, L2SR, INFO, WRU? routers receive: HRTO, GVL2, WRU?, INFO routers send: RDRC, L2SR, INFO, WRU? Level-C: nodes send: HRTO, GVL2, WRU?, INFO, TELL nodes receive: RDRC, L2SR, INFO, WRU? routers receive: HRTO, GVL2, WRU?, INFO, TELL routers send: RDRC, L2SR, INFO, WRU? Level-D: nodes send: HRTO, GVL2, WRU?, INFO nodes receive: RDRC, L2SR, INFO, WRU? routers receive: HRTO, GVL2, WRU?, INFO, GVRT, RTBL routers send: RDRC, L2SR, INFO, WRU?, GVRT, RTBL This RRP1 document defines the 7 messages required for Levels B and C (HRTO, RDRC, GVL2, L2SR, TELL, INFO, and WRU?). The RRP2 document defines the 2 messages required for Level D (GVRT and RTBL). In addition, a few error messages are also defined. Cohen et al [Page 7] Internet-Draft PktWay Router-to-Router Protocol October 1997 6. Node Attributes Each node must have a Physical Address. Optionally it may also have Name, Capabilities, and Logical-Addresses: Physical Address: 23 bits, flat, unique in this PktWay. Name: flat, globally unique (e.g., IP address), arbitrary length Capabilities: regular GP node, router, PktWay-server, NFS, paging server, M/C server, SRVLOC-server, DSP, printer,... Some capabilities may need additional parameters (e.g., SAN-ID for routers, and resolution+colors for printers). There parameters are capability-specific. The capabilities are defined in the PktWay Enumeration document. Logical-Addresses: a set of (logical) addresses to which this node requests to listen. Logical addresses designate multicast and broadcast groups. The control of the Logical-Addresses (a la IGMP) is not defined in this document. This will be designed by the applications that use it (e.g., PktWay-multicast). The management of logical addresses (e.g., JOIN and LEAVE) is not defined here. Cohen et al [Page 8] Internet-Draft PktWay Router-to-Router Protocol October 1997 7. RRP Messages RRP messages are PktWay messages with PT="RRP" and TE=RRP-type, in their EEP-header, followed by some (zero or more) RRP-records according to their RRP-type, followed (always) by the PktWay-TAIL which is the EI field. The RRP-records constitute the Data Block (DB) of the PktWay-message. They must be in Big-Endians order, with e=0 in the EEP-header. Following are the 7 RRP messages (for Level B and C), with their RRP-type, and the related error messages. The column S->D (Source to Destination) shows who sends such messages to whom, where N is for Node, H is for HR, and A is for Any. RRP- Type S->D Description -------- ------ ----------------------------------------------- [GVL2] N->H Please give me L2-routes to node (address) Replies to [GVL2]: [L2SR], [RDRC], or [ERR/UNK]. [L2SR] H->N Here are L2-routes to node (address) [HRTO] N->H Which HR should I use for node (address)? Replies to [HRTO]: [RDRC] or [ERR/UNK]. [RDRC] H->N Re-direct to node (address) via an HR on same SAN [TELL] N->H Please tell me about node (address, name, capa's) The reply to [TELL] is [INFO], or [ERR/UNK]. [INFO] A->A Info about node (address, name, capabilities, LAs) [WRU?] A->A Who/what-Are-You? (Tell me all about yourself) The reply to [WRU?] is [INFO] about the replier. RRP also uses the following error messages: [ERR/UNK] Destination Unknown (address) [ERR/HRDOWN] HR Down [ERR/LKDOWN] Link Down [ERR/GENERAL] General error message Cohen et al [Page 9] Internet-Draft PktWay Router-to-Router Protocol October 1997 8. RRP Message Structure The RRP-messages are made of RRP-records, distinguished by their Record-Type (RTyp). These RRP records are: RTyp Description ---- ---------------------------------- ADDR Address NAME Name CAPA Capability LADR Logical Addresses SRQR Source Route and its Quality (SR,Q) MTUR MTU (for the preceding SRQR) The RRP-records are made of 8B-words. The following shows the RRP-records that make each of the RRP-messages. Each message starts with a PH (PktWay-header), and ends with a PT (PktWay-TAIL). The TAIL is not shown here. * [GVL2] Please give me L2-routes from you to node (address) PH (with [PT/TE]=[RRP/GVL2]) ADDR (address of the node for which SR is requested) * [L2SR] Here are L2-routes from me to node (address) PH (with [PT/TE]=[RRP/L2SR]) ADDR (address of the node for which SR is provided) SRQR (SR with Q) possibly with a few L2RH records MTUR (MTU for the above SR) This message may have several (SRQR,MTUR)s, one for each SR. * [HRTO] Which HR should I use for node (address) PH (with [PT/TE]=[RRP/HRTO]) ADDR (address of the node for which initial HR is requested) * [RDRC] Re-direct to destination node (address) via a HR (address), on the same SAN. PH (with [PT/TE]=[RRP/RDRC]) ADDR (address of the destination node) ADDR (address of the HR to be used for that destination) The above addresses are expected to be physical (but they be otherwise). Cohen et al [Page 10] Internet-Draft PktWay Router-to-Router Protocol October 1997 * [TELL] Please tell me about node (address | name | capabilities) PH (with [PT/TE]=[RRP/TELL]) ADDR (address of that node) or PH (with [PT/TE]=[RRP/TELL]) NAME (name of that node) or PH (with [PT/TE]=[RRP/TELL]) CAPA (capabilities for which nodes are requested) This message may have several CAPA's, one for each capability. [TELL] identifies a node by an address and/or a name and/or capabilities. If more than one attribute is specified (e.g., an address and name(s)) any nodes that meets any of them should be considered (like an implied OR). * [INFO] Info about node(s) (address, name, capabilities) PH (with [PT/TE]=[RRP/INFO]) ADDR (address of that node) NAME (name of that node) CAPA (capabilities for which nodes are requested) LADR (Logical-Addresses for the requested node) This message may have several CAPA's, one for each capability. For nodes without NAME, LADR, or any CAPA, these records are omitted. [INFO] provides all the known information about all the nodes that match the [TELL]. The [ADDR} records are the separators between the nodes. * [WRU?] (CD) Who/what-Are-You? PH (with [PT/TE]=[RRP/WRU?] and [DD]=0x7FFFFE) * [ERR/UNK] Destination Unknown (address) PH (with [PT/TE]=ERROR/UNK) XXXX (XXXX of the Destination node for which the requested information is not available), where XXXX is the ADDR and/or NAME and/or CAPA of the node(s) about which this message is sent Cohen et al [Page 11] Internet-Draft PktWay Router-to-Router Protocol October 1997 * [ERR/HRDOWN] HR Down (or Router-Down) PH (with [PT/TE]=[ERROR/HRDOWN]) ADDR (address of the HR that is down) ADDR (the other address of the router that is down) * [ERR/LINKDOWN] Link Down PH (with [PT/TE]=[ERROR/LINKDOWN]) ADDR (address of one end of the link that is down) ADDR (address of the other end of the link that is down) * [ERR/GENERAL] General Error (i.e., none of the above) PH (with [PT/TE]=[ERROR/GENERAL]) XX (The entire message that caused the error PH+OH+DB+TAIL) 9. RRP Record Format Each RRP-record starts with an 8B-word header as shown below. Its first byte identifies the record type (RTyp). The second byte is the Pad-Count byte (PL) indicating the number of padding bytes. The third and the fourth bytes (RL) are the length (in 8B-words) of the record, excluding the record header, hence it may be zero. The rest of the header bytes depend on the record type (RTyp). +--------+--------+--------+--------+--------+--------+--------+--------+ | RTyp | PL | RL |........|........|........|........| +--------+--------+--------+--------+--------+--------+--------+--------+ Some records that have an arbitrary length are "right justified" and have PL padding bytes before the data. Padding Before Data [PBD]. Some records that have an arbitrary length are "left justified" and have PL bytes after the data. Padding After Data [PAD]. In either case the total number of data bytes is: (8*RL+4-PL). Following are the RRP-records. These records are the building blocks used to construct RRP-messages. In the following xxxx indicate bytes that are discarded, such as for padding. It is recommended to set them to all-0. Cohen et al [Page 12] Internet-Draft PktWay Router-to-Router Protocol October 1997 ===> [ADDR] Node-Address Record [PAD] This record specifies either a single address (with AT=1) or a range of addresses (with AT=2 followed by AT=3, or by AT=4 followed by AT=5). AT is the "Address-Type". 0 1 2 3 4 5 6 7 +--------+--------+--------+--------+--------+--------+--------+--------+ | "ADDR" | PL=0 | RL=0 | AT=1 | PktWay-Address | +--------+--------+--------+--------+--------+--------+--------+--------+ or: 0 1 2 3 4 5 6 7 +--------+--------+--------+--------+--------+--------+--------+--------+ | "ADDR" | PL=4 | RL=1 | AT=2 | Min-PktWay-Address | +--------+--------+--------+--------+--------+--------+--------+--------+ | AT=3 | Max-PktWay-Address | xxxx | xxxx | xxxx | xxxx | +--------+--------+--------+--------+--------+--------+--------+--------+ or: 0 1 2 3 4 5 6 7 +--------+--------+--------+--------+--------+--------+--------+--------+ | "ADDR" | PL=4 | RL=1 | AT=4 | PktWay-Address-Value | +--------+--------+--------+--------+--------+--------+--------+--------+ | AT=5 | PktWay-Address-Mask | xxxx | xxxx | xxxx | xxxx | +--------+--------+--------+--------+--------+--------+--------+--------+ The address-mask follows the address-value. The above addresses may be physical or logical. The address X is specified by an ADDR record if: if AT=1: X == PktWay-Address if AT=2,3: Min-PktWay-Address <= X <= Max-PktWay-Address if AT=4,5: (PktWay-Address-Mask & X) == PktWay-Address-Value An ADDR-record defines only one PktWay-address (or one range), unlike an LADR record (see below) that may specify multiple addresses and multiple address-ranges. If the ADDR record is followed by other records that describe the same node (such as NAME, CAPA, LADR, SRQR, and MTUR) then the RL of the ADDR records also covers all these records. All these records apply to all the addresses specified in this ADDR-record. Needless to say that NAME is not expected to appear within a record that specifies more than one address. Cohen et al [Page 13] Internet-Draft PktWay Router-to-Router Protocol October 1997 Hence, if an ADDR-record with AT=1 has RL>1, or if an ADDR-record with AT>1 has RL>2, then this ADDR-record includes additional records (such as CAPA, LADR, SRQR, and/or MTUR) about the specified address(es). The enumeration is guaranteed not to have overlap between the AT and the RTyp codes. ===> [NAME] Node-Name Record [PAD] (e.g., a name with 7 bytes B1..B7) 0 1 2 3 4 5 6 7 +--------+--------+--------+--------+--------+--------+--------+--------+ | "NAME" | PL=3 | RL=1 | B1 | B2 | B3 | B4 | +--------+--------+--------+--------+--------+--------+--------+--------+ | B5 | B6 | B7 | xxxx | xxxx | xxxx | xxxx | xxxx | +--------+--------+--------+--------+--------+--------+--------+--------+ The number of bytes in the name is 8*RL+4-PL. ===> [CAPA] Node-Capability Record [PAD] (e.g., 9 parameter bytes): 0 1 2 3 4 5 6 7 +--------+--------+--------+--------+--------+--------+--------+--------+ | "CAPA" | PL=2 | RL=1 | CC=Cx | P1 | P2 | P3 | +--------+--------+--------+--------+--------+--------+--------+--------+ | P4 | P5 | P6 | P7 | P8 | P9 | xxxx | xxxx | +--------+--------+--------+--------+--------+--------+--------+--------+ Byte#4 is the Capability Code, CC, followed by as many parameter bytes as needed (9 in the above example). The capability codes are listed in the PktWay Enumeration document. The number of bytes used by the parameters is 8*RL+3-PL. Cohen et al [Page 14] Internet-Draft PktWay Router-to-Router Protocol October 1997 ===> [LADR] Logical-Addresses Record [PAD] (e.g., 2 logical addresses and a range of logical addresses) 0 1 2 3 4 5 6 7 +--------+--------+--------+--------+--------+--------+--------+--------+ | "LADR" | PL=4 | RL=2 | AT=1 |1110 Logical-Address-#1 | +--------+--------+--------+--------+--------+--------+--------+--------+ | AT=2 |1110 Min-Logical-Address | AT=3 |1110 Max-Logical-Address | +--------+--------+--------+--------+--------+--------+--------+--------+ | AT=1 |1110 Logical-Address-#2 | xxxx | xxxx | xxxx | xxxx | +--------+--------+--------+--------+--------+--------+--------+--------+ Whereas an ADDR-record defines only one PktWay-address (or one range), an LADR record may specify multiple addresses (each with AT=1) and multiple ranges (each with a pair of AT=2,3 or AT=4,5). ===> [SRQR] Source-Route Record [PBD], with Q for that route. (e.g., an SR combined of 2 L2RHs, one with 13 bytes and one with 4 bytes) This record carries one, or more, L2RHs (2 in the following example, one with SR of 13B, followed by an SR of 5B). 1 2 3 4 5 6 7 +--------+--------+--------+--------+--------+--------+--------+--------+ | "SRQR" | PL=2 | RL=3 | xxxx | xxxx | Q | +--------+--------+--------+--------+--------+--------+--------+--------+ |vv000000|10 L=13B| SR01 | SR02 | SR03 | SR04 | SR05 | SR06 | +--------+--------+--------+--------+--------+--------+--------+--------+ | SR07 | SR08 | SR09 | SR10 | SR11 | SR12 | SR13 | xxxx | +--------+--------+--------+--------+--------+--------+--------+--------+ |vv000000|10 L=4B | SR01 | SR02 | SR03 | SR04 | xxxx | xxxx | +--------+--------+--------+--------+--------+--------+--------+--------+ Q (the Route Quality) is an unsigned 16-bit integer. The units are not defined here. It is assumed that it is monotonic with all-0 being the best and all-1 the worst. If there is an MTUR (MTU-record) for that SR it should follow this SRQR record. However, the RL of the SRQR does not include the RL of the MTUR. ===> [MTUR] MTU record [PBD]: 0 1 2 3 4 5 6 7 +--------+--------+--------+--------+--------+--------+--------+--------+ | "MTUR" | PL=0 | RL=0 | MTU (in 8B-words) | +--------+--------+--------+--------+--------+--------+--------+--------+ The MTU record provides the MTU for the SR defined before (by an SRQR). The value of 0 means indefinite MTU (i.e., any length is OK). Cohen et al [Page 15] Internet-Draft PktWay Router-to-Router Protocol October 1997 10. Examples for RRP Message Node-S asks HR1 to provide an L2RH to node-X: ==> [GVL2] Please give me L2-routes from you to node-X 0 1 2 3 4 5 6 7 +--------+--------+--------+--------+--------+--------+--------+--------+ |00 P |0 HR1-Address | "GVL2" | "R R P" | +---+----+--------+--------+--------+-+------+--------+--------+--------+ |E=0|PL=0| Data-Length=1 (8B-words) |0| RZ |0 S-Address | +---+----+--------+--------+--------+-+------+--------+--------+--------+ | "ADDR" | PL=0 | RL=0 | AT=1 |0 X-Address | +--------+--------+--------+--------+--------+--------+--------+--------+ | 64 zero bits, unless any error was indicated along the path | +--------+--------+--------+--------+--------+--------+--------+--------+ ==> [L2SR] HR1 replies with two L2-routes to node-X with Qs and MTUs (e.g., an SR of 2 L2RHs (of 5+4 bytes), and an SR of 1 L2RH of 3 bytes) 0 1 2 3 4 5 6 7 +--------+--------+--------+--------+--------+--------+--------+--------+ |00 P |0 S-Address | "L2SR" | "R R P" | +---+----+--------+--------+--------+-+------+--------+--------+--------+ |E=0|PL=0| Data-Length=8 (8B-words) |0| RZ |0 HR1-Address | +---+----+--------+--------+--------+-+------+--------+--------+--------+ | "ADDR" | PL=0 | RL=7 | AT=1 |0 X-Address | +--------+--------+--------+--------+--------+--------+--------+--------+ | "SRQR" | PL=2 | RL=2 | xxxx | xxxx | Q | +--------+--------+--------+--------+--------+--------+--------+--------+ |vv000000|10 L=5B | SR01 | SR02 | SR03 | SR04 | SR05 | xxxx | +--------+--------+--------+--------+--------+--------+--------+--------+ |vv000000|10 L=4B | SR01 | SR02 | SR03 | SR04 | xxxx | xxxx | +--------+--------+--------+--------+--------+--------+--------+--------+ | "MTUR" | PL=0 | RL=0 | MTU (in 8B-words) | +--------+--------+--------+--------+--------+--------+--------+--------+ | "SRQR" | PL=2 | RL=1 | xxxx | xxxx | Q | +--------+--------+--------+--------+--------+--------+--------+--------+ |vv000000|10 L=3B | SR01 | SR02 | SR03 | xxxx | xxxx | xxxx | +--------+--------+--------+--------+--------+--------+--------+--------+ | "MTUR" | PL=0 | RL=0 | MTU (in 8B-words) | +--------+--------+--------+--------+--------+--------+--------+--------+ | 64 zero bits, unless any error was indicated along the path | +--------+--------+--------+--------+--------+--------+--------+--------+ Cohen et al [Page 16] Internet-Draft PktWay Router-to-Router Protocol October 1997 ==> [RDRC] HR1 redirects Node-S to use HR2 for node-X 0 1 2 3 4 5 6 7 +--------+--------+--------+--------+--------+--------+--------+--------+ |00 P |0 S-Address | "RDRC" | "R R P" | +---+----+--------+--------+--------+-+------+--------+--------+--------+ |E=0|PL=0| Data-Length=2 (8B-words) |0| RZ |0 HR1-Address | +---+----+--------+--------+--------+-+------+--------+--------+--------+ | "ADDR" | PL=0 | RL=0 | AT=1 | X-Address | +--------+--------+--------+--------+--------+--------+--------+--------+ | "ADDR" | PL=0 | RL=0 | AT=1 | HR2-Address | +--------+--------+--------+--------+--------+--------+--------+--------+ | 64 zero bits, unless any error was indicated along the path | +--------+--------+--------+--------+--------+--------+--------+--------+ ==> [TELL] Please tell about Node-X (address | name | capabilities) This message may have any of the following 3 forms: If by PktWay-address: 0 1 2 3 4 5 6 7 +--------+--------+--------+--------+--------+--------+--------+--------+ |00 P |0 HR1-Address | "TELL" | "R R P" | +---+----+--------+--------+--------+-+------+--------+--------+--------+ |E=0|PL=0| Data-Length=1 (8B-words) |0| RZ |0 S-Address | +---+----+--------+--------+--------+-+------+--------+--------+--------+ | "ADDR" | PL=0 | RL=0 | AT=1 | X-Address | +--------+--------+--------+--------+--------+--------+--------+--------+ | 64 zero bits, unless any error was indicated along the path | +--------+--------+--------+--------+--------+--------+--------+--------+ If by name (e.g., a name with 9 characters: A1...A9): 0 1 2 3 4 5 6 7 +--------+--------+--------+--------+--------+--------+--------+--------+ |00 P |0 HR1-Address | "TELL" | "R R P" | +---+----+--------+--------+--------+-+------+--------+--------+--------+ |E=0|PL=0| Data-Length=2 (8B-words) |0| RZ |0 S-Address | +---+----+--------+--------+--------+-+------+--------+--------+--------+ | "NAME" | PL=3 | RL=1 | A1 | A2 | A3 | A4 | +--------+--------+--------+--------+--------+--------+--------+--------+ | A5 | A6 | A7 | A8 | A9 | xxxx | xxxx | xxxx | +--------+--------+--------+--------+--------+--------+--------+--------+ | 64 zero bits, unless any error was indicated along the path | +--------+--------+--------+--------+--------+--------+--------+--------+ Cohen et al [Page 17] Internet-Draft PktWay Router-to-Router Protocol October 1997 If by capabilities (e.g., 2 capabilities, C1 with 2 parameter bytes, and C2 with no parameter bytes): 0 1 2 3 4 5 6 7 +--------+--------+--------+--------+--------+--------+--------+--------+ |00 P |0 HR1-Address | "TELL" | "R R P" | +---+----+--------+--------+--------+-+------+--------+--------+--------+ |E=0|PL=0| Data-Length=2 (8B-words) |0| RZ |0 S-Address | +---+----+--------+--------+--------+-+------+--------+--------+--------+ | "CAPA" | PL=1 | RL=0 | CC=C1 | P1 | P2 | xxxx | +--------+--------+--------+--------+--------+--------+--------+--------+ | "CAPA" | PL=3 | RL=0 | CC=C2 | xxxx | xxxx | xxxx | +--------+--------+--------+--------+--------+--------+--------+--------+ | 64 zero bits, unless any error was indicated along the path | +--------+--------+--------+--------+--------+--------+--------+--------+ A [TELL] may specify several nodes, by addresses, names, and capabilities. Any node that matches any of the specifications in [the TELL] should be included in the replying [INFO], in separate ADDR records. ==> [INFO] Info about Node-X (address, name, capabilities) e.g., a name with 9 characters (A1...A9) and 3 capabilities (Cx, Cy, and Cz): 0 1 2 3 4 5 6 7 +--------+--------+--------+--------+--------+--------+--------+--------+ |00 P |0 S-Address | "INFO" | "R R P" | +---+----+--------+--------+--------+-+------+--------+--------+--------+ |E=0|PL=0| Data-Length=7 (8B-words) |0| RZ |0 HR1-Address | +---+----+--------+--------+--------+-+------+--------+--------+--------+ | "ADDR" | PL=0 | RL=6 | AT=1 | X-Address | +--------+--------+--------+--------+--------+--------+--------+--------+ | "NAME" | PL=3 | RL=1 | A1 | A2 | A3 | A4 | +--------+--------+--------+--------+--------+--------+--------+--------+ | A5 | A6 | A7 | A8 | A9 | xxxx | xxxx | xxxx | +--------+--------+--------+--------+--------+--------+--------+--------+ | "CAPA" | PL=1 | RL=0 | CC=Cx | P1 | P2 | xxxx | +--------+--------+--------+--------+--------+--------+--------+--------+ | "CAPA" | PL=3 | RL=0 | CC=Cy | xxxx | xxxx | xxxx | +--------+--------+--------+--------+--------+--------+--------+--------+ | "CAPA" | PL=5 | RL=1 | CC=Cz | P1 | P2 | P3 | +--------+--------+--------+--------+--------+--------+--------+--------+ | P4 | P5 | P6 | xxxx | xxxx | xxxx | xxxx | xxxx | +--------+--------+--------+--------+--------+--------+--------+--------+ | 64 zero bits, unless any error was indicated along the path | +--------+--------+--------+--------+--------+--------+--------+--------+ Cohen et al [Page 18] Internet-Draft PktWay Router-to-Router Protocol October 1997 The INFO records should specify all the nodes that meet any of the attributed specified in the TELL record. When such aggregation is used, the DL (data length) in the PH is the sum of the (RL+1)s of all the ADDR fields. (*) The ADDR, NAME, and CAPA records are repeated for each applicable node. Same also for LADR, SRQR, and MTUR, if any. If several capabilities are specified in [TELL], any node that has any of these capabilities should be reported in [INFO]. ==> [HRTO] Node-S asks HR1 which HR to use for Node-X. 0 1 2 3 4 5 6 7 +--------+--------+--------+--------+--------+--------+--------+--------+ |00 P |0 HR1-Address | "HRTO" | "R R P" | +---+----+--------+--------+--------+-+------+--------+--------+--------+ |E=0|PL=0| Data-Length=1 (8B-words) |0| RZ |0 S-Address | +---+----+--------+--------+--------+-+------+--------+--------+--------+ | "ADDR" | PL=0 | RL=0 | AT=1 | X-Address | +--------+--------+--------+--------+--------+--------+--------+--------+ | 64 zero bits, unless any error was indicated along the path | +--------+--------+--------+--------+--------+--------+--------+--------+ ==> [WRU?] Who/what-Are-You? 0 1 2 3 4 5 6 7 +--------+--------+--------+--------+--------+--------+--------+--------+ |00 P |01111111|11111111|11111110| "WRU?" | "R R P" | +---+----+--------+--------+--------+-+------+--------+--------+--------+ |E=0|PL=0| Data-Length=0 (8B-words) |0| RZ |0 S-Address | +---+----+--------+--------+--------+-+------+--------+--------+--------+ | 64 zero bits, unless any error was indicated along the path | +--------+--------+--------+--------+--------+--------+--------+--------+ This is addressed to 0x7FFFFE, the "Hey-You" address. Cohen et al [Page 19] Internet-Draft PktWay Router-to-Router Protocol October 1997 ==> [ERR/UNK] Destination Unknown (address). HR1 tells Node-S that he does not know about Node-X. 0 1 2 3 4 5 6 7 +--------+--------+--------+--------+--------+--------+--------+--------+ |00 P |0 S-Address | UNK | "E R R" | +---+----+--------+--------+--------+-+------+--------+--------+--------+ |E=0|PL=0| Data-Length=1 (8B-words) |0| RZ |0 HR1-Address | +---+----+--------+--------+--------+-+------+--------+--------+--------+ | "ADDR" | PL=0 | RL=0 | AT=1 | X-Address | +--------+--------+--------+--------+--------+--------+--------+--------+ | 64 zero bits, unless any error was indicated along the path | +--------+--------+--------+--------+--------+--------+--------+--------+ This message reports that host (X) is unknown to S. ==> [ERR/HRDOWN] HR Down (2 addresses). HR1 tells Node-S that HR-X is down 0 1 2 3 4 5 6 7 +--------+--------+--------+--------+--------+--------+--------+--------+ |00 P |0 S-Address | "HRDOWN" | "E R R" | +---+----+--------+--------+--------+-+------+--------+--------+--------+ |E=0|PL=0| Data-Length=2 (8B-words) |0| RZ |0 HR1-Address | +---+----+--------+--------+--------+-+------+--------+--------+--------+ | "ADDR" | PL=0 | RL=0 | AT=1 | HRX-Address-1 | +--------+--------+--------+--------+--------+--------+--------+--------+ | "ADDR" | PL=0 | RL=0 | AT=1 | HRX-Address-2 | +--------+--------+--------+--------+--------+--------+--------+--------+ | 64 zero bits, unless any error was indicated along the path | +--------+--------+--------+--------+--------+--------+--------+--------+ HR1 knows 2 addresses of the downed router. ==> [ERR/LINKDOWN] Link Down (2 addresses) 0 1 2 3 4 5 6 7 +--------+--------+--------+--------+--------+--------+--------+--------+ |00 P |0 S-Address | "LINKDOWN" | "E R R" | +---+----+--------+--------+--------+-+------+--------+--------+--------+ |E=0|PL=0| Data-Length=2 (8B-words) |0| RZ |0 HR1-Address | +---+----+--------+--------+--------+-+------+--------+--------+--------+ | "ADDR" | PL=0 | RL=0 | AT=1 | A-Addr | +--------+--------+--------+--------+--------+--------+--------+--------+ | "ADDR" | PL=0 | RL=0 | AT=1 | B-Addr | +--------+--------+--------+--------+--------+--------+--------+--------+ | 64 zero bits, unless any error was indicated along the path | +--------+--------+--------+--------+--------+--------+--------+--------+ This message reports that the link between A-Addr and B-Addr is down. Cohen et al [Page 20] Internet-Draft PktWay Router-to-Router Protocol October 1997 ==> [ERR/GENERAL] General error: HR1 tells node-S that it (HR1) could not handle the enclosed message) 0 1 2 3 4 5 6 7 +--------+--------+--------+--------+--------+--------+--------+--------+ |00 P |0 S-Address | GENERAL | "E R R" | +---+----+--------+--------+--------+-+------+--------+--------+--------+ |E=0|PL=0| Data-Length=? (8B-words) |0| RZ |0 HR1-address | +---+----+--------+--------+--------+-+------+--------+--------+--------+ | | |<------The entire message that could not be handled by the sender----->| | | +--------+--------+--------+--------+--------+--------+--------+--------+ | 64 zero bits, unless any error was indicated along the path | +--------+--------+--------+--------+--------+--------+--------+--------+ This message reports that the enclosed message could not be handled by its receiver (the sender of this error message). 11. Appendix-A: Example of the use of RRP The following PktWay is used for the example. It included 3 SANs, interconnected via 2 routers, Router-A (RTRA) between SAN1 and SAN3, and RTRB between SAN1 and SAN2. +-------+ +--0--+ SAN1 +--0--+ +--0--+ | Node1 +----------3 SW0 1----------3 SW1 1----------3 SW2 1 MTU=16KB +-------+ +--2--+ +--2--+ +--2--+ | | RTRA1 *********** +---+---+ *********** RTRB1 * RouterA * | Node2 | * RouterB * RTRA3 *********** +---+---+ *********** RTRB2 | | | +-------+ SAN3 +--0--+ +--0--+ SAN2 +--0--+ | Node3 +----------3 SW3 1 3 SW4 1----------3 SW5 1 MTU=8KB +-------+ +--2--+ +--2--+ +--2--+ In this example Node1 on SAN1 (with MTU=16KB) is looking for Node2 which is on SAN2 (with MTU=8KB). It first asks its default router (RTRA1) for an L2RH to Node2. RTRA1 redirects Node1 to RTRB1 regarding Node2. Node1 asks RTRA1 (by [HRTO], in message M1) which router to use for Node2. RTRA1 suggests (using [RDRC], M2) to use RouterB. Node1 uses L3-forwarding ([WRU?], M3), via Router-B, to verify that RTRB can indeed get to Node2, by asking Node2 for information about itself. Node2 provides this information ([TELL], M4) which Node1 likes. Node1 asks RouterB ([GVL2], M5) for L2RH(s) to Node2. RouterB provides ([L2SR], M6) the requested L2RH with its MTU of 1,024 8B-words (8KB). Cohen et al [Page 21] Internet-Draft PktWay Router-to-Router Protocol October 1997 Finally, Node1 sends data (by M7) to Node2 using L2-forwarding. Similarly, Node2 may ask its default router which HR to use for Node1 and for L2RH(s) to Node1. If Node1 had only Level-A implementation then it should have the combined L2RH from itself to RouterB and from there to Node2 pre-wired, saving all this message exchange. The sequence of messages (M1 thru M7) is shown below. (M1) Node1 sends [HRTO] to its default router RTRA1 asking which HR to use for node2. 0 1 2 3 4 5 6 7 +-----------------------------------------------------------------------+ | <---- The L2-header needed to get from Node1 to RouterA1 ----> | | It may be any number of bytes. In this example it's 9 bytes:230000000| +--------+--------+--------+--------+--------+--------+--------+--------+ |00 P |0 RTRA1 | "HRTO" | "R R P" | +---+----+--------+--------+--------+-+------+--------+--------+--------+ |E=0|PL=0| Data-Length=1 (8B-words) |0| RZ |0 Node1 | +---+----+--------+--------+--------+-+------+--------+--------+--------+ | "ADDR" | PL=0 | RL=0 | AT=1 |0 Node2 | +--------+--------+--------+--------+--------+--------+--------+--------+ | 64 zero bits, unless any error was indicated along the path | +--------+--------+--------+--------+--------+--------+--------+--------+ (M2) RTRA1 uses [RDRC] to re-direct to Node2 via RouterB. 0 1 2 3 4 5 6 7 +-----------------------------------------------------------------------+ | <---- The L2-header needed to get from RouterA1 to Node1 ----> | | It may be any number of bytes. In this example it's 9 bytes:330000000| +--------+--------+--------+--------+--------+--------+--------+--------+ |00 P |0 Node1 | "RDRC" | "R R P" | +---+----+--------+--------+--------+-+------+--------+--------+--------+ |E=0|PL=0| Data-Length=2 (8B-words) |0| RZ |0 RTRA1 | +---+----+--------+--------+--------+-+------+--------+--------+--------+ | "ADDR" | PL=0 | RL=0 | AT=1 |0 Node2 | +--------+--------+--------+--------+--------+--------+--------+--------+ | "ADDR" | PL=0 | RL=0 | AT=1 |0 RTRB1 | +--------+--------+--------+--------+--------+--------+--------+--------+ | 64 zero bits, unless any error was indicated along the path | +--------+--------+--------+--------+--------+--------+--------+--------+ Node1 knows how to get to RouterB over its SAN. Cohen et al [Page 22] Internet-Draft PktWay Router-to-Router Protocol October 1997 (M3) Node1 uses [WRU?] (still using L3-forwarding via RouterB) to verify the capabilities of Node-2, and that RTRB can indeed get to it. This is done by asking Node2 for information about itself. 0 1 2 3 4 5 6 7 +-----------------------------------------------------------------------+ | <---- The L2-header needed to get from Node1 to RouterB1 ----> | | It may be any number of bytes. Here it is 11 bytes: 11230000000 | +--------+--------+--------+--------+--------+--------+--------+--------+ |00 P |0 Node2 | "WRU?" | "R R P" | +---+----+--------+--------+--------+-+------+--------+--------+--------+ |E=0|PL=0| Data-Length=0 (8B-words) |0| RZ |0 Node1 | +---+----+--------+--------+--------+-+------+--------+--------+--------+ | 64 zero bits, unless any error was indicated along the path | +--------+--------+--------+--------+--------+--------+--------+--------+ (M4) Node2 uses [INFO] (via RouterB2, also using L3-forwarding) to provide information about itself to Node1. This info includes its PktWay-address and its name ("Super"). If Node2 had implemented also Level-C of the RRP it would also provide a record about its capabilities (as shown in this example with 2 capabilities (with codes of 5 and 7). 0 1 2 3 4 5 6 7 +-----------------------------------------------------------------------+ | <---- The L2-header needed to get from Node2 to RouterB2 ----> | | It may be any number of bytes. Here it is 10 bytes: 1030000000 | +--------+--------+--------+--------+--------+--------+--------+--------+ |00 P |0 Node1 | "INFO" | "R R P" | +---+----+--------+--------+--------+-+------+--------+--------+--------+ |E=0|PL=0| Data-Length=5 (8B-words) |0| RZ |0 Node2 | +---+----+--------+--------+--------+-+------+--------+--------+--------+ | "ADDR" | PL=0 | RL=4 | AT=1 |0 Node2 | +--------+--------+--------+--------+--------+--------+--------+--------+ | "NAME" | PL=7 | RL=1 | "S" | "u" | "p" | "e" | +--------+--------+--------+--------+--------+--------+--------+--------+ | "r" | xxxx | xxxx | xxxx | xxxx | xxxx | xxxx | xxxx | +--------+--------+--------+--------+--------+--------+--------+--------+ | "CAPA" | PL=1 | RL=0 | CC=7 | 4 | 8 | xxxx | +--------+--------+--------+--------+--------+--------+--------+--------+ | "CAPA" | PL=3 | RL=0 | CC=5 | xxxx | xxxx | xxxx | +--------+--------+--------+--------+--------+--------+--------+--------+ | 64 zero bits, unless any error was indicated along the path | +--------+--------+--------+--------+--------+--------+--------+--------+ By receiving this message Node1 knows that RTRB could indeed be used for communication with Node2. Cohen et al [Page 23] Internet-Draft PktWay Router-to-Router Protocol October 1997 (M5) Node1 uses [GVL2] to ask RouterB for L2RH(s) from RouterB to Node2. 0 1 2 3 4 5 6 7 +-----------------------------------------------------------------------+ | <---- The L2-header needed to get from Node1 to RouterB1 ----> | | It may be any number of bytes. Here it is 11 bytes: 11230000000 | +--------+--------+--------+--------+--------+--------+--------+--------+ |00 P |0 RTRB1 | "GVL2" | "R R P" | +---+----+--------+--------+--------+-+------+--------+--------+--------+ |E=0|PL=0| Data-Length=1 (8B-words) |0| RZ |0 Node1 | +---+----+--------+--------+--------+-+------+--------+--------+--------+ | "ADDR" | PL=0 | RL=0 | AT=1 |0 Node2 | +--------+--------+--------+--------+--------+--------+--------+--------+ | 64 zero bits, unless any error was indicated along the path | +--------+--------+--------+--------+--------+--------+--------+--------+ (M6) RouterB uses [L2SR] to provide Node1 with an L2RH from RTRB2 to Node2, with its Q and MTU. This L2RH is {3,0,3,0,0,0,0,0,0,0} from RouterB to Node2, and the MTU is 1,024 (meaning 8KB). 0 1 2 3 4 5 6 7 +-----------------------------------------------------------------------+ | <---- The L2-header needed to get from RouterB1 to Node1 ----> | | It may be any number of bytes. Here it is 11 bytes: 33330000000 | +--------+--------+--------+--------+--------+--------+--------+--------+ |00 P |0 Node1 | "L2SR" | "R R P" | +---+----+--------+--------+--------+-+------+--------+--------+--------+ |E=0|PL=0| Data-Length=4 (8B-words) |0| RZ |0 RTRA1 | +---+----+--------+--------+--------+-+------+--------+--------+--------+ | "ADDR" | PL=0 | RL=3 | AT=1 |0 Node2 | +--------+--------+--------+--------+--------+--------+--------+--------+ | "SRQR" | PL=2 | RL=1 | xxxx | xxxx | Q | +--------+--------+--------+--------+--------+--------+--------+--------+ |vv000000|10 L=4B | 3 | 0 | 3 | 0 | xxxx | xxxx | +--------+--------+--------+--------+--------+--------+--------+--------+ | "MTUR" | PL=1 | RL=0 | MTU=1,024 (in 8B-words) | +--------+--------+--------+--------+--------+--------+--------+--------+ | 64 zero bits, unless any error was indicated along the path | +--------+--------+--------+--------+--------+--------+--------+--------+ The MTU in the MTUR above is the lessor of the MTUs of both networks. The RL (record-length) of the last MTUR-record is NOT included in the RL of the preceding SRQR-record, but is included in the RL of the preceding ADDR-record (since the RL of the SRQR is included in the RL of the ADDR). The RL=3 of the ADDR includes 2 words of SRQR and 1 word of MTUR. Cohen et al [Page 24] Internet-Draft PktWay Router-to-Router Protocol October 1997 (M7) Finally, Node1 sends data to Node2 using L2-forwarding. 0 1 2 3 4 5 6 7 +-----------------------------------------------------------------------+ | <---- The L2-header needed to get from Node1 to RouterB1 ----> | | It may be any number of bytes. Here it is 11 bytes: 11230000000 | +--------+--------+--------+--------+--------+--------+--------+--------+ |vv000000|10 L=4B | 3 | 0 | 3 | 0 | xxxx | xxxx | +--------+--------+--------+--------+--------+--------+--------+--------+ |00 P |0 Node2 |Sensor.SubType=? | "Sensor" | +---+----+--------+--------+--------+-+------+--------+--------+--------+ |E=3|PL=0| Data-Length=? (8B-words) |0| RZ |0 Node1 | +---+----+--------+--------+--------+-+------+--------+--------+--------+ | | | <------------------- The sensor data goes here ---------------------> | | | +--------+--------+--------+--------+--------+--------+--------+--------+ | 64 zero bits, unless any error was indicated along the path | +--------+--------+--------+--------+--------+--------+--------+--------+ E=3 (0b0011) indicates that all the data is 64-bit, Big Endian order. Again, if Node1 had only Level-A implementation then it would have pre-wired the combined L2RH from itself to RouterB and from there to Node2, saving all this message exchange. All the messages shown in this appendix start with local L2 routing bytes needed to get across either SAN1 or SAN2 (indicated with "The L2-header needed to get from ... to ...") which are not L2RHs. The difference is that these bytes are in front of the packet, exposed to the local switches, whereas the L2RHs are only exposed to PktWay-entities. These local L2 routing bytes are the actual bytes required by the SANs and likely to be consumed as the messages traverses the SAN, unlike the L2RHs that are intact until converted to actual routing bytes. The L2RHs start with 0bvv00000010 followed by the number of routing bytes in that L2RH, and possibly also by several bytes of padding. Cohen et al [Page 25] Internet-Draft PktWay Router-to-Router Protocol October 1997 12. Appendix-B: Glossary Address: A unique designation of a node (actually an interface to that node) or a SAN. Buddy-HR: HRs are "buddies" if they are on the same SAN. Cut-Thru: See wormhole. Destination: The node to which a packet is intended Dynamic-Routing: Routing according to dynamic information (i.e., acquired at run time, rather than pre-set). Endianness: The property of being Big-Endian or Little-Endian (transmission order, etc.) Ethertype: A 16-bit value designating the type of Level-3 packets carried by a Level-2 communication system. HR: Half-Router, the part of a router that handles one network only. L2-Forwarding: Forwarding based on Level-2 (i.e., data-link layer of the ISORM) information, e.g., the native technique of each SAN or LAN. Also called "source routing." L3-Forwarding: Forwarding based on end-to-end (Level-3 i.e., network layer of the ISORM) addresses. Also called "destination routing." Map: The topology of a network. Mapper: A node on a SAN/LAN that has the map and an RT for that network. It is expected that the mapper dynamically updates the map and the RT. Multi-homed Node: A node with more than one network interface, where each interface has another address. Node: Whatever can send and receive packets (e.g., a computer, an MPP, a software process, etc.) Node structure: A C-struct (or equivalent) containing values for some attributes of a node. Planned Transfer: Transfer of information, occurs after an initial phase in which the sender decides which Level-2 route to use for that transfer. RCVF: The "Received From" set includes all the physical addresses through which an RT was disseminated, starting with the address of the mapper that created that RT. Re-direct-message: A message that tells nodes which HR should be used in order to get to a certain remote address. Router: The inter-SAN communication device Security Context: A relationship between 2 (or more) nodes that defines how the nodes utilize security services to communicate securely. Source: The node that created a packet. Source-Route: A Level-2 route that is chosen for a packet by its source. Symbol: Data preceding the EEP header of a PktWay message, interleaving with the L2RHs. Cohen et al [Page 26] Internet-Draft PktWay Router-to-Router Protocol October 1997 Twin-HR: Two HRs are twins if they both are parts of the same inter-SAN router. Wormhole-routing: (aka cut-thru routing) forwarding packets out of switches as soon as possible, without storing that entire packet in the switch (unlike Stop-and-forward) Zero-copy TCP: A TCP system that copies data directly between the user area and the network device, bypassing OS copies 13. Appendix-C: Acronyms and Abbreviations 0bNNNN The binary number NNNN (e.g., 0b0100 is 4-decimal) 0xNNNN The hexadecimal number NNNN (e.g., 0x0100 is 256-decimal) 8B 8 byte (64 bits) entity ADDR The Address-record of RRP APIn Application/Program Interface AT Address Type ATM Asynchronous Transmission Mode B Byte (e.g., 4B) b bit (e.g., 32b) BC Byte Count (of parameters) BER Bit Error Rate CAPA The CAPAbility-record of RRP CC Capability Code CSR Common Source-Route DA Destination Address DB Data Block DL Data Length (in 8B words) DSP Digital Signal Processor DT Destination-Type E The Endianness field (in the EEP header) e The MSbit of E EEP End/End Protocol EI Error Indication GP General Purpose GVL2 An RRP message, requesting L2 route to a given destination GVRT An RRP message asking an HR to give its routing tables h Optional header fields flag HR Half Router HRTO An RRP message asking which HR to use for a given destination ID Identification IGMP Internet Group Management Protocol INFO An RRP message providing information about nodes IP The Internet protocol ISORM The ISO Reference Model L Length field (exclusive of itself) L2 Level-2 of the ISORM (Link) L2RH Level-2 Routing Header L2SR Source Route L3 Level-3 of the ISORM (Network) LA Logical Address LADR The Logical-addresses-record of RRP Cohen et al [Page 27] Internet-Draft PktWay Router-to-Router Protocol October 1997 LAN Local Area Network LRT Local Routing Table LSbit Least Significant bit LSbyte Least Significant byte MAC Message Authentication Code / Media Access Control MPI Message Passing Interface MPP Massively Parallel Processing system MSbit Most Significant bit MSbyte Most Significant byte MSU Mississippi State University MTU Maximum Transmission Unit MTUR The MTU-record of RRP M/C Multicast NAME The name-record of RRP NFS Network File Server OH Optional Header field OH-TYPE The Type of an Optional Header field OT Optional Trailer field P The Priority field PAD Padding After Data PBD Padding Before Data PCI The Peripheral Component Interconnect "standard" PH PacketWay Header PL Padding Length (always in bytes) PPP The Point-to-Point Protocol PROM Programmable ROM (Read-Only-Memory) PT Packet Type (2B) PVM Parallel Virtual Machine PW The Myrinet Packet Type assigned to PktWay (PW=0x0300) Q Quality (of a path) RCVF Received-From list, or the Received-From record of RRP RDRC A re-direct message of RRP RH Routing Header RID Record ID RL Record Length (in 8B-words) RRP Router/Router Protocol RT-hd RT (Routing Table) header RT Routing Table RTBL An RRP message proving a Routing Table RTHD The Routing-Table-Header record of RRP RTyp RRP's Record Type RZ The Reserved field (in the EEP header) SA Source Address SAN System Area Network SAN-ID The 24-bit PktWay-address of a SAN SAR Segmentation and Reassembly SN Serial Number SNID SAN-ID SNMP Simple Network Management Protocol SR Source Route (always at Level-2) SRQR The Source-Route-and-Q-record of RRP ST Symbol Type Cohen et al [Page 28] Internet-Draft PktWay Router-to-Router Protocol October 1997 TAIL PacketWay EEP Trailer TE Type Extension (2B) TELL RRP message requesting INFO about a partially specified node UNK Unknown V Version WRU? An RRP message asking its recipient to identify itself XRT External Routing Table xxxx A padding byte 14. Appendix-4: PktWay at a Glance (aka "The Cheat-Sheet") 2 6 type 24 16 16 +-+------+-------+--------+---------+--------+--------+--------+--------+ |V| P | Destination-Type | Type-Extension | Packet-Type | +-+-+---++--------------------------+-+------+--------+-----------------+ | E | PL| Data-Length (8B-words) |h| RZ |0 Source-Address | +---+---+--------+--------+---------+-+------+--------+--------+--------+ 4 3 25 1 7 1 23 type = 0xxx Physical Address 10xx L2RH 110x Reserved 1110 Logical Address 1111 Symbols L2RH: 2 6 2 6 8 8 8 8 8 8 +--------+--------+--------+--------+--------+--------+--------+--------+ |V| P |10LLLLLL| SR01 | SR02 |........|........|........|........| +--------+--------+--------+--------+--------+--------+--------+--------+ Length Symbol: 2 6 4 6 8 8 8 8 8 8 +--------+--------+--------+--------+--------+--------+--------+--------+ |V| P |1111ssss|ssssssss|ssssssss| Length | data |........|........| +--------+--------+--------+--------+--------+--------+--------+--------+ <---- Symbol Type ---> Optional Header: 2 6 8 8 8 8 8 8 8 +--------+--------+--------+--------+--------+--------+--------+--------+ |TCtttttt|LLLLLLLL| data |........|........|........|........|........| +--------+--------+--------+--------+--------+--------+--------+--------+ T: 0=optional, 1=mandatory; C: 0=more OH-fields follow, 1=last OH-field RRP Record: 8 8 8 8 8 8 8 8 +--------+--------+--------+--------+--------+--------+--------+--------+ | RTyp | PL | RL |........|........|........|........| +--------+--------+--------+--------+--------+--------+--------+--------+ RRP-messages: GVL2, L2SR, RDRC, TELL, INFO, HRTO, WRU?, GVRT, RTBL; RTyp: ADDR, NAME, CAPA, LADR, SRQR, MTUR, RCVF, RTHD; Cohen et al [Page 29] Internet-Draft PktWay Router-to-Router Protocol October 1997 15. Security Considerations This RFC raises no security issues. PktWay is designed to work in clusters to which the access may be as controlled as needed. PktWay has a security applique for securing the comminucation between classified/sensitive clusters, even when non-secure clusters and non-secure communication facilities have to be used. This applique uses cryptographic methods and equipment. More about that applique may be found in "Proposed Specification for Security Extensions to the PacketWay Protocol" {http://WWW.ERC.MsState.Edu/labs/hpcl/packetway/secure.txt}. At the presence of security threats such applique should be used 16. Editor's Address Danny Cohen Myricom, Inc. 325 N. Santa Anita Ave Arcadia, CA 91006 Phone: 626-821-5555 Fax: 626-821-5316 Email: Cohen@myri.com Cohen et al [Page 30]