Network Working Group P. Karp Request for Comments: XXXX MITRE NIC: 5761 26 February 1971
Categorization and Guide to NWG/RFCs
The NWG/RFC Guide is an attempt to introduce some order into the NWG/RFC series, which now numbers 102. The Guide categorizes the NWG/RFC notes, identifies topics under discussion and the relevant NWG/RFCs, and indicates whether the notes are current, obsolete, or superseded.
A minimum subset of NWG/RFCs is identified. This subset consists of the NWG/RFCs that one should read to quickly become familiar with the current status of topics.
For historical reasons and for readers interested in tracing through the stages of development of a topic, a brief summary is given for each NWG/RFC relevant to a particular category.
This initial Guide is being issued as a NWG/RFC since it establishes the basis for future releases. So, please comment! Suggestions, criticism, corrections, etc., will be accepted for a period of approximately two weeks. Be critical as I have not had to implement an NCP and probably have some misconceptions regarding various technical points. An official version will be released on March 26. The Guide will then be a unique series of documents, separate from NWG/RFCs (as is the Document No. 1, No. 2 series).
With regard to renumbering NWG/RFCs, I am inclined to keep she sequential numbering scheme presently employed. The main reason for this position is that the current numbers have both historical and semantic significance. For example, reference to "#33, #66, #83, etc." is a convenient shorthand (reminiscent of the old corny joke about joke #s) used extensively during meetings. The list of "current status" NWG/RFC numbers should dispel any fear of maintaining stacks of NWG/RFCs for quick reference. The subject is not closed, however, and I will entertain any objections, suggestions, etc.
GUIDE TO NETWORK WORKING GROUP/REQUEST FOR COMMENTS
The NWG/RFC notes are partitioned into 9 categories, which in turn are divided into subcategories. For each category the official document (if any), unresolved issues, and documents to be published are identified.
Karp [Page 1]
RFC 100 Categorization & Guide to NWG/RFC's 26 February 1971
For each subcategory, relevant NWG/RFCs are listed and a brief description of the topics addressed in each note is given.
The categories are again listed and the current NWG/RFCs identified (p. 23). The NWG/RFCs in the list comprise the subset defining "current status". Note that most of the documentation in the subset addresses topics in Category D - Subsystem Level Protocol, where at the present time most issues are unresolved.
Finally, the NWG/RFCs are listed by number, with a reference to the relevant categories (p. 26).
The distribution list contains names, addresses, and phone numbers for recipients of NWG/RFCs. The most recent list, NWG/RFC 95, designates the Technical Liaison as the recipient for each site and supersedes all other RFCs in this category.
General network working group meetings are held approximately every three months. Special subcommittee meetings are held on an ad hoc basis. All related NWG/RFCs are obsolete except 87, announcing a graphics meeting to be held at MIT in April and 99, announcing a general NWG meeting, Atlantic City, May 16-20.
The NWG/RFC Guide categorizes the NWG/RFC notes, identifies topics under discussion, the relevant NWG/RFCs, and denotes whether the notes are current, obsolete, or superseded. Included in this category are lists of NWG/RFCs, ordered by number (as in 84) and/or by author.
72, 73, 77, and 82 discuss the decision to delay making changes to the Host/Host protocol in order to first gain experience with the network. A committee to propose specific changes has been formed.
37 discusses changes to the Host/Host protocol and the schedule for introducing modifications.
53 sets forth the mechanism for establishing and modifying the official Host/Host protocol.
17 raised several questions regarding HOST/IMP protocol. In 17a,BBN responds to the questions.
19 proposes that the hosts control the ordering of IMP/Host traffic rather than getting messages delivered in the order received by the IMP. This proposal is counter to BBN's position, specifically expressed in 47; that is, buffering is a Host rather than an IMP function. The purpose of buffering in the IMP is to handle surges of traffic, thus IMP buffers should be empty. NWG/RFC 19 is obsolete.
21 discusses changes to BBN Memo No. 1822. The remarks are obsolete.
33 contains a general description of the interface between a host and the IMP. NWG/RFC 47 comments on NWG/RFC 33.
The use of RFNMs (type 10 and type 5 messages) to control flow is discussed in NWG/RFCs 36, 37 and 46. The official position in "cease on link" (i.e., discontinue the mechanism) is presented in 102 and renders obsolete the remarks in 36, 37, and 46.
38 discusses the changes to message format that would be necessary if multiplexing connections over links was allowed.
Karp [Page 4]
RFC 100 Categorization & Guide to NWG/RFC's 26 February 1971
102 presents the decision of the Host/Host protocol committee to abandon the marking convention and to ignore padding. The issue of whether to have the first data byte begin after 72 bits of header or to use double physical transmission (NWG/RFC #s 65, 67) is discussed.
The former official position is expressed in 54: "All regular messages consist of a 32 bit leader, marking, text, and padding. Marking is a (possibly null) sequence of zeros followed by a 1; padding is a 1 followed by a (possibly null) sequence of zeros."
Several proposals to eliminate marking have been made. 64 suggests a hardware modification to eliminate marking/padding by adding appropriate counters to Host/IMP interfaces. 65 suggests breaking regular messages into two messages. 67 supports 65. 72 and 73 suggest that such changes be postponed until sufficient experience with the network is gained.
44 introduces the notion of double padding and presents two alternative approaches when a message does not end on a Host word boundary:
a) The host provides padding in addition to the IMPS ("double padding")
b) The host shifts messages to end on a word boundary.
48 explains double padding in more detail and discusses the pros and cons. A suggestion is made to use marking to adjust the word baundary (alternative b). NWG/RFCs 49 and 50 are concurrences with 48.
70 presents a method to handle the stripping of padding from a message.
All NWG/RFCs in this category have been superseded by 102.
Host/Host protocol specifies the procedures by which connections for inter-Host interprocess communication over the network are established, maintained, and terminated. The software which implements the protocol within each Host is called the Network
Karp [Page 5]
RFC 100 Categorization & Guide to NWG/RFC's 26 February 1971
Control Program (NCP). The topics included in this category are connection establishment and termination, flow control, interrupt handling, error control and status testing, dynamic reconnection, and the relationship between connections and links.
Official documents: Document No. 1 by S. Crocker, 3 August 1970, with modifications presented in NWG/RFC 102.
Unresolved issues: Length of control messages Location in message of first byte of data Flow control algorithm Socket identification format
To be published: Document No. 2 will be written by S. Crocker and will resolve the first three issues. A NWG/RFC will be written by J. Heafner, in collaboration with E. Meyer and G. Grossman. presenting the pros and cons on alternative proposals for socket number identification.
The official Host/Host protocol presented in Document No. 1 is based on the proposals, discussions, acceptance, and rejection of ideas in the above list of NWG/RFCs, up to and including 59.
In particular:
9, 11, and 22 represent an early attempt at a Host/Host protocol. 11 supersedes 9 and 22 contains some modifications to control message formats presented in 11. The protocol was not considered powerful enough because it didn't provide for inter-host communication without logging in. This protocol was thrown out as a result of a network meeting in December 1969.
33 is the basis for the current protocol. It was presented at the SJCC, 1970.
36 is a modification of 33. It discusses connection establishment without switching, flow control, and introduces the idea of reconnection. Control commands are summarized. 36 was distributed at a Network meeting in March 1970.
Karp [Page 6]
RFC 100 Categorization & Guide to NWG/RFC's 26 February 1971
37 presents the reaction to 36 and presents ideas on reconnection flow control and decoupling of links and connections. Provisions of error detection, status testing, experimentation and expansions are discussed.
38, 39, 40, 44, 49 and 50 are comments written in response to the meeting. 46 is also a comment but in the form of a rewrite of 33. 46 introduces the notion of interrupts, INT, and ECO for status testing.
47 concerns the philosophy behind the notion of a link.
48 summarizes the issues discussed in the above NWG/RFCs.
54 is the initial official protocol submitted for criticism, comments, etc. It introduces a new mechanism for flow control in which the receiving host allocates buffer space and notifies the sending host of the space available.
Document No. 1 differs from NWG/RFC 54 as follows: commands GVB and RET have been added for flow control and error condition codes have been added to ERR. NWG/RFC 102 presents some modifications to Document No. 1: fixed lengths are specified for ECO, ERP, and ERR; a new pair of commands RST and RRP (suggested in 57) are added.
60, 61, and 62 propose new Host/Host protocols, quite different from the current official protocol. 62 supersedes 61. 60 and 62 are worth considering for possible implementation in future protocols. Hopefully, more documents of a similar nature will be generated as experience is gained with the current protocol.
NWG/RFCs 65 and 68 comment on Document No. 1.
93 points out an ambiguity in Document No. 1 regarding the requirement of a message data type in the message sent from server socket 1. The ambiguity is resolved by 102 which eliminates message data type from level 2 protocol.
This category includes RFCs which give details of system calls, table structures, implementation techniques, etc.
Karp [Page 7]
RFC 100 Categorization & Guide to NWG/RFC's 26 February 1971
In particular:
NWG/RFCs 9, 11, and 22 are obsolete
23 is a general statement on sending or receiving multiple control messages in a single communication.
33 discusses the system calls used for interaction between the NCP and a user process.
36 describes a possible implementation giving table structures and their interrelationships.
44 lists the system calls that SDC feels should operate, includes spec. of calls to NCP.
NWG/RFC 48 presents Postel's and Crocker's view on the environment in which a host time-sharing system operates, suggests some system calls, and presents a design to illustrate the components of an NCP.
55 presents a prototypical NCP which implements the initial official protocol specified in 54. It is offered as an illustrative example.
70 gives some techniques for stripping the padding from a message.
71 presents the method employed by the CCN-Host at UCLA to resynchronize flow control when an input error occurs.
74 documents the implementation of sections of the NCP at UCSB.
89 gives a brief description of the "interim interim NCP" (IINCP) on the MIT Dynamic Modeling PDP-6/10 used to run some experiments.
The NWG/RFCs in this category present the system calls and control commands used to establish and terminate connections, i.e., the handshaking that must transpire before connections are established or terminated.
In particular:
36 presents a rough scenario of connection establishment which differs from that specified in 33 in that establishment does not include procedures for switching procedures.
Karp [Page 8]
RFC 100 Categorization & Guide to NWG/RFC's 26 February 1971
39 suggests the addition of a command TER to supplement CLS.
44 discusses the use of the CLS command and suggests that two commands BLS and CLS be adopted.
46, 46, and 50 all discuss queuing of RFCs.
54 presents the initial official method for establishing and terminating connections.
60 and 62 present schemes different from the official protocol.
The NWG/RFCs in this category address the problem of controlling the flow of messages from the sending socket to the receive socket. The official position is stated in Document No. 1 with an unresolved issue pending as described in NWG/RFC 102.
In particular:
19 suggests that Hosts may want the capability of agreeing to lock programs into core for more efficient core-to-core transfers. This may require different handling of RFNMs.
33 describes the use of RFNM (type 10 rather than 5) on a link to control flow. A control command RSM (resume) is defined to allow the host to signal for resumption of message flow. 46 describes the same technique.
37 describes the effect some proposed changes (for reconnect and decoupling of connections and links) would have on RFNMs and "cease on link."
46 (MIT's rewrite of protocol) introduces BLK and RSM commands as an alternative to "cease on link", SPD and RSM commands.
47 presents BBN's position that buffering be handled by the Host, not the IMP.
54 introduces a new flow control mechanism in which the receiving host is required to allocate buffer space for each connection and not notify the sending host of bit sizes. A new command, ALL to allocate space is sent from the receiving host to the sending host. With this new mechanism, 33, 37, 46, and 47 become obsolete.
Karp [Page 9]
RFC 100 Categorization & Guide to NWG/RFC's 26 February 1971
59 presents the objections of Project MAC and Lincoln Labs to the flow control mechanism introduced in 54. Their preference is for "cease on link" which allocates buffer space on demand.
60, which defines a simplified NCP protocol, presents a method of flow control based on the requirement that connections are full duplex.
65 comments on Document No. 1. With respect to flow control, it disagrees with the allocation mechanism and the introduction of irregular message to make the cease mechanism work.
68 proposes modifications to RFNM by defining three forms which would insure control of data and would replace the memory allocation mechanism.
102 eliminates the cease mechanism and introduces potential modifications to the flow control mechanism. The latter will be resolved and presented in Document No. 2.
This category addresses schemes for detecting and controlling errors and for Host status reporting and testing.
In particular:
2 talks about error checking and gives an algorithm for implementing a checksum. It also recommends that Hosts should have a mode in which positive verification of all messages is required.
37 brings up the topics of error detection and status testing, which are expanded by RAND in 39 and 40. 39 introduces control commands ERR for error checking and QRY, HCU, and HGD for status testing. 40 expands on the discussion, suggests error codes, introduces RPY as a response to QRY, and suggests that NOP could be used for reporting Host status.
46 concurs with 40 on ERR and introduces ECO to test communication between NCPs.
48 recommends that ERR, as presented in 40 and 46, be adopted, that a distinction be made between resource errors and other error types, that ECO, presented in 46, be of variable length, and that an ECO, ERP command pair be adopted.
Karp [Page 10]
RFC 100 Categorization & Guide to NWG/RFC's 26 February 1971
54 officially specifies the control commands ERR, ECO, and ERP. The official protocol doesn't include a specific list of error types nor does it recommend the action to be taken. Suggestions for extensions to error detection and recovery and Host/Host status testing are encouraged.
57 presents a list of error types and suggests new commands OVF for overflow errors and RST/RSR for host status testing.
102 sets fixed lengths for ERR, ECO, and ERP control commands. RST and RSR are adopted.
The interrupt system call and the INT control commands are used to interrupt a process. This is actually a third level issue. The NWG/RFCs leading up to the decision to include INR and INS in the official protocol are summarized below.
In particular:
46 introduces the INT command as a method for interrupting a process.
48 recommends adoption of INT with the restriction that the feature should not be used during communication with systems which scan for interrupts and that INT should not be used on non-console type connections (see D.2).
49 expands on the explanation of INT. 50 concurs with proposal 46, that INT is useful.
54 induces INT, INS control commands in the official protocol as an escape mechanism, where interpretation is a local matter.
102 discusses synchronization of interrupt signals, presents two implementation schemes, and relegates the topic to third level protocol. INS should be used to indicate a special code in the input stream.
The notion of dynamic reconnection was introduced early in the Host/Host protocol design. However, the consensus was that it introduced complexities with which the initial NCP implementations
Karp [Page 11]
RFC 100 Categorization & Guide to NWG/RFC's 26 February 1971
did not want to cope. The need for dynamic reconnection was questioned; NWG/RFC 48 explains why it was included and considered useful.
In particular:
33 introduces the concept of switching connections to the Logger. 36 presents a scheme for dynamic reconnection, i.e., reconnection can take place after the flow is started.
37 presents two methods suggested by BBN for handling reconnection.
38 discusses changes to proposed END and RDY control commands that would be necessary if connections were multiplexed over links.
39 states that dynamic reconnection is too complex.
44 presents two cases where reconnection could be used, suggests that the cases be separated, and recommends implementation of only the case of a simple connection switch within the same Host.
46 recommends that dynamic reconnection be reserved for further Host/Host protocol implementations.
48 discusses the aesthetics of dynamic reconnection in detail but concedes that it won't be included in the initial protocol. 49 and 50 concur with the decision.
A connection is an extension of a link. The NWG/RFCs in this category discuss this relationship.
In particular:
37 presents the pros and cons on decoupling connections and links. 38 recommends that connections be multiplexed over links. Two cases where this would be useful are presented. The effect on the proposed protocol is discussed. Both 37 and 38 suggest the inclusion of the destination socket as part of the text of the message and recommend that messages should be send over any unblocked link.
44 suggests the use of link numbers in control commands (except RFSs) due to the 1 to 1 correspondence between links and foreign socket numbers.
Karp [Page 12]
RFC 100 Categorization & Guide to NWG/RFC's 26 February 1971
48 recommends leaving links and connections coupled.
Other topics that fall into the category of Host/Host protocol are:
Marking/Padding: see B.2
Record/Message Boundaries: see D.5
Experimentation and Expansion. The assignment of links for experimentation and expansion is discussed in NWG/RFC #s 37 and 48.
Instance Tag: The addition of an instance tag to the socket identifier is introduced in 46, is supported by 49 and 50, and is not recommended in 48. The matter is unresolved (see "To be published", section C).
Broadcast Facility: A control command to implement a broadcast facility as introduced in 39. It was not supported in 48.
To be published: Three committees have been set up to address user level issues, specifically: logger, console, and TELNET protocols (D.1, D.2, D.3); data transformation (D.4); and, graphics protocol (D.6). Status reports will be published prior to the next Network meeting (May 1971). In addition, a companion paper to 98 discussing console protocol has been promised by MIT MAC and G. Grossman (Ill.) will issue an RFC proposing a file transmission protocol.
Logger Protocol specifies the procedures by which a user gets connected to a remote Host. The logger is a process, always in execution, which listens for login requests.
Karp [Page 13]
RFC 100 Categorization & Guide to NWG/RFC's 26 February 1971
In particular:
33 proposes that the logger listen to calls on socket #0. It then switches to the assigned socket. The sequence of events is illustrated.
46 proposes a User Control and Communication (UCC) module, which implements logger protocol and permits the logger to interact with the NCP. It proposes the use of two full-duplex pseudo-typewriter connections.
48 proposes that sockets <U, H, 0> and <U, H, 1> designate either the input and output sockets of a copy of the logger or the console sockets.
49 is a write-up of a combination of the proposals presented in 46 and 48. 49 presents the disadvantages of the new proposal and reverts back to supporting the UCC of 46.
50 indicates RAND support for the UCC presented in 46.
56 defines a send-logger and a receive-logger with a full-duplex connection. The logger handles one request at a time; requests are queued. The receiver logger is identified as user 0 on socket 0.
66 introduces a dial-up protocol (Initial Connection Protocol, ICP) to get a process at one site in contact with the logger at another site.
74 documents the logger implemented at UCSB.
77 and 82 report the discussion of logger protocol at the FJCC 1970 Network meeting. E. Harslem and E. Meyer agreed to write proposals.
79 discusses a conflict between Document No. 1 and NWG/RFC 66 regarding the use of ALL prior to connection establishment.
80 presents a variation of 66 that rectifies the conflict. 80 also suggests that ICP should apply to more than just the logger i.e., let user 0 signify the logger.
88 documents the logger implemented as part of NETRJS, which allows access to RJS at UCLA's CCN. The ICP described in 66 and 80 is adhered to. The logger is designated as user 0.
91 contains a description of the logger for the PDP-10 at Harvard.
Karp [Page 14]
RFC 100 Categorization & Guide to NWG/RFC's 26 February 1971
93 points out an ambiguity in the Host/Host protocol of Document No. 1 regarding the requirement of message data type for ICP. The ambiguity is rectified by NG/RFC 102.
97 includes the ICP (as proposed in 80) used to establish connection to NIC.
98 is the logger protocol proposal issued by E. Meyer.
Console protocol will specify conventions for what goes out over the network. Included are conventions for echoing, character set, interrupt or break, end of line, message formats.
In particular:
20 suggests a standard of 7-bit ASCII in an 8-bit byte, with the high order bit 0.
44 discusses three possibilities for echoing over the network (echoing, no echoing, optional echoing) and states a preference for no echoing. 44 also states a preference for establishing a network common code where all code conversion is performed on outgoing text; thus, all incoming text would be in the common code.
46 proposes the use of interrupt on the third level. An interrupt means "quit" when sent from a requestor process to a created process. The command level is entered.
48 and 49 relegate issues of echoing and code conversion to third level protocol.
50 and 56 support adoption of ASCII for the network standard character set. 56 also discusses two uses of break characters (interrupt): in a panic situation and to exit from subsystem. Three message formats (character by character, end by carriage return, several command lines per message) are discussed. A recommendation that echoing be handled locally is made.
66 specifies that the standard console use 7-bit ASCII in 8 bits with the 8th bit on (note the conflict with 20). It also specifies the use of INR for break or interrupt.
74 documents console protocol implemented by UCSB.
Karp [Page 15]
RFC 100 Categorization & Guide to NWG/RFC's 26 February 1971
77 and 82 report on console protocol topics (echoing, full vs half duplex) discussed at the Network meeting, FJCC 1970.
88 documents conventions used by NETRJS for RJS at CCN, UCLA.
91 discusses code standards.
96 and 97 document conventions used for NIC at SRI ARC.
98 proposes specifications for general console communications and addresses full vs half duplex, character escapes, and action characters.
TELNET is a subsystem permitting a teletype-like terminal at a remote Host for function as a teletype at the serving Host. TELNET protocol specifies user level interface to the network by way of network system calls.
In particular:
15 introduces the TELNET concept and presents a sample dialogue between Utah's PDP-10 and SRI's 940. System primitives are proposed.
33 describes TELNET and gives essentially the same example as in 15.
76 describes a terminal user control language for Illinois's PDP-11 ARPA Network Terminal System. The protocol defined permits the user to utilize the network at a symbolic level.
80 and 83 introduce the concept of a Protocol Manager that can manage protocol sequences between consoles and the network. The Form Machine (see D.4) can be used for translations.
91 contains a proposal for a User/User protocol that has the ability to function as TELNET.
96 describes a series of experiments to be conducted using the TELNET subsystem at SRI ARC.
97 presents a detailed proposal for a standard TELNET protocol.
Karp [Page 16]
RFC 100 Categorization & Guide to NWG/RFC's 26 February 1971
NIL, DEL, and Form Machines are proposals of similar methods for adapting user programs and/or data to the network. A committee chaired by J. Heafner has been formed to plan, implement, and exercise a language for reconfiguring data streams.
In particular:
NIL (Network Interchange Language), described in 51, introduces the concept of an abstract network machine which would permit a user to consider the computer network as an overall computing facility. All dialogue would take place between hosts and the network machine. NIL permits the description of the environment and the description of the Front End of an interactive system. Sublanguages for describing control, operation, data declaration, and environment are used. With NIL, the network machine can operate in standard mode as well as user-defined extended mode. The network machine can act as a user of a Host; conversely, a Host can be a user of a network machine. Each Host will have a generator to generate a translator from the descriptive sublanguage inputs.
DEL (Decode - Encode Language), described in 5, utilizes a front end translator at the using site to translate the using site characters to the server host character set. Return messages are subsequently translated locally to the local standard. Immediate feedback in an interactive mode is also handled locally. DEL can be used for the operation of large display-oriented systems. Provisions are given for representing a universal hardware. The syntax is included.
Two proposals for the Form Machine have been given. 80 introduces the concept of the Form Machine, an experimental software package operating on regular expressions that describe data formats. 83 presents a different approach: a syntax-driven interpreter which operates on a grammar which is an _ordered_ set of replacement rules. 83 contains a description of the Form Machine with some examples of replacement rules for particular data types. Application of the Form-Machine to program protocols is also discussed.
31 proposes a message description language as a standard symbolic method for defining and describing binary messages. In the future, the descriptive language could be used as input to generators of data translation programs.
42 proposes the use of message data types prior to the development of network languages specifying the syntax and semantics of messages.
Karp [Page 17]
RFC 100 Categorization & Guide to NWG/RFC's 26 February 1971
Programs would extract the message data type and transform the data accordingly. Both standard and local types would be handled (as in RFC #51), probably using tables stored at one location such as NIC. 62 presents data typed codes.
96 includes a discussion on a Front End for NLS (T) and suggests that further study be given to standard languages as presented in 51.
Positions that no special structures should be imposed on data transmission are presented in 49 and 91. 50 and 58 disagree. 58 claims that logical and physical message distinctions exist and that logical messages must begin on a physical message boundary.
63 reports a decision from a meeting that records may begin anywhere in a message. In a later meeting, 77 and 82, the issue was reopened. Discussion included consideration of methods of indicating the end of message and alternatives were given. Earlier RFCs had discussed these alternatives: 13 proposes a 0 length message to specify EOF; 50 proposes use of a bit count preceding the transmission and discusses solutions to the problem of dropping bits.
Proposals specifying network graphics protocol are in the formative stages.
In particular:
43 mentions LIL, in interpretable language at Lincoln Labs that can handle interactive graphics.
77 and 82 discuss the formation of a working group to specify procedures for using graphics over the network.
80 states that graphics oriented descriptions will added to the Form Machine.
86 is a proposal for a network standard format for a data stream to control graphics displays. 87 announces a network graphics meeting to be hosted by MIT and suggests discussion topics. Both 86 and 87 are attempts to stimulate some interest in the generation of graphics protocol proposals.
Karp [Page 18]
RFC 100 Categorization & Guide to NWG/RFC's 26 February 1971
89 describes a Harvard-MIT graphics experiment using the network.
94 comments on 8 and presents an alternate proposal.
The subject of file transmission over the network is at the informal discussion stage. Nothing substantive has been published as NWG/RFCs om this category.
In particular:
13 proposes using a 0 length message to specify EOF.
38 recommends routing multiple connections over the same link to handle file transmissions over the network.
77 and 82 summarize comments on file transmission problems aired at the Network meeting in Houston, Nov. 1970.
91 describes how PDP-10 file transmission could be handled over the network.
Both 77 and 82 report on the comments made at the Network meeting, Houston 1970, regarding network measurements. UCLA and BBN are officially responsible for gathering network statistics. Is it reasonable to alter the NCP to keep statistics?
The NWG/RFCs in this category discuss requirements for a clock to measure network delay.
Karp [Page 19]
RFC 100 Categorization & Guide to NWG/RFC's 26 February 1971
In particular:
28 is concerned with the installation of a real-time clock at SRI ARC and requests comments concerning network time standards for delay measurement.
29 responds to 28, stating that a millisecond clock should be sufficient.
32 discusses the desirability of adding a network clock for measurement of user-oriented message delays. A one millisecond resolution is a reasonable specification. The problems of clock synchronization and long term accuracy are addressed.
Reports on experience with the network are starting to be published. As sites begin to get their NCPs up, more notes in this category should be generated and are encouraged.