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
<draft-ietf-pktway-protocol-rrp1-spec-00.txt>
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
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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.
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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).
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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.
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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).
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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).
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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.
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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.
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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
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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).
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* [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
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* [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.
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===> [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.
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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.
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===> [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).
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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 |
+--------+--------+--------+--------+--------+--------+--------+--------+
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==> [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 |
+--------+--------+--------+--------+--------+--------+--------+--------+
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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 |
+--------+--------+--------+--------+--------+--------+--------+--------+
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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.
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==> [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.
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==> [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).
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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.
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(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.
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(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.
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(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.
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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.
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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
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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
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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;
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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
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