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Some comments on the official protocol (RFC0117)

IP.com Disclosure Number: IPCOM000001982D
Original Publication Date: 1971-Apr-07
Included in the Prior Art Database: 2000-Sep-12
Document File: 3 page(s) / 7K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

J. Wong: AUTHOR

Abstract

[Categories B.1, C.1, C.2, C.3, C.4, C.5]

This text was extracted from a ASCII Text document.
This is the abbreviated version, containing approximately 45% of the total text.

Network Working Group J. Wong

Request for Comments: 117 UCLA

NIC #5826 7 April 1971

Some Comments on the Official Protocol

[Categories B.1, C.1, C.2, C.3, C.4, C.5]

Document No. 1 and NWG/RFC No. 107 gave a very detailed description of

connection establishment, connection termination and flow control over

the Network. Throughout the implementation of the NCP it was

discovered that the handling of ERR control commands, messages of

types other than 0 (regular), 4 (nop), and 5 (rfnm), and messages with

the From-imp bit on are not well discussed so that problems arise when

they occur.

The Protocol is not complete if the above situations are not handled

clearly, and the Host-Host Protocol Glitch Cleaning Committee should

take this into consideration. In this document, experience with these

unfavorable situations and suggestions for handling are given:

1. ERR Control Commands

In Document No. 1, the following error conditions are described:

a. Illegal Op. code.

b. End of message encountered before all expected parameters.

c. Bad socket polarity within commands.

d. Link number not in the range of 0 <= L < 32.

e. A request (other than RTS/STR) on a non-existent socket.

f. A request (ALL, GVB, RET, INR, INS) on a non-existent link

number.

g. Transmit over non-existent link number.

Other error conditions are:

h. A request (GVB, RET, INR, INS) on an existent link, but

connection is not established.

i. Transmit over an existent link, but connection is not

established.

j. ALL or GVB on a send connection.

k. RET on a receive connection.

l. An attempt to send more than the allocated number of bits or

messages.

m. ECO, ERP, ERR commands do not have the defined number of bits

of data.

In Document No. 1, each site is supposed to document the information

on their ERR command. No one has done that so far, and the main

reason is we are not sure of what information is important. In

NWG/RFC No. 107, the text portion of the ERR Commands is decided to

have a fixed length of 80 bits because 80 bits is long enough to hold

the longest non-ERR command. In some of the above error conditions,

more information than the command itself is desirable. It was noted

that these error conditions arise very often in the experimental stage

of the NCP. If every NCP is operating properly, none of them should

ever occur. The ERR commands are therefore, an excellent debugging

tool for the protocol. So it is desirable to define a set of possible

error conditions, and for each condition, define a set of arguments in

the corresponding ERR command so that enough information is given to

tell what's wrong. The suggested arguments for each situation (a - m)

are listed below:

a. 1. Op. code in error.

2. Part of message following op. code (A maxim...