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Comments on a proffered official ICP: RFCs 123, 127 (RFC0151) Disclosure Number: IPCOM000002339D
Original Publication Date: 1971-May-10
Included in the Prior Art Database: 2000-Sep-12
Document File: 2 page(s) / 3K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

A. Shoshani: AUTHOR



This text was extracted from a ASCII document.
This is the abbreviated version, containing approximately 82% of the total text.

NWG/RFC # 151 A. Shoshani


NIC #6755 May 10, 1971


(RFCs 123, 127)

Bob Long at SDC noticed that the order in which messages go out to the

network depend on the local NCP. In particular commands may be given

priority over data and therefore in the sequence specified for server in

RFC 123 (top of Page 3), the last two INIT commands may go out before the

data = S on socket = L is sent. (This is the case in the current

implementation of SDC's NCP.) The implication is that the user's NCP should

be prepared to keep the INIT's it received from the server until the user

process gets the data = S and issues two INITs in response.

This case is brought up now so that people will think about it before the

Atlantic City meeting and comment whether their NCP can tolerate it. It may

be necessary to make it explicit in the ICP that the two INITs sent by the

server should go out only after the data = S is sent, or even after the

user process acknowledges its receipt.

I have a more general remark about the ICP. This is a third level protocol

and therefore should not alter or ignore procedures of the second level

protocol (Host-Host protocol). In particular three remarks seem


1. In RFC 123 (bottom of Page 2) it is suggested that the byte size for the

connection to the server socket L is 32. However, in the modifications

to second level protocol (RDC 107) it is specified that it is up to the

sending process to chose the byte size. According to the Host-Host

protocol, NCPs should be prepared to accept messages in any byte size

(1<= size <=255); therefore there is no need to impose a size of 32 in

this case. Furthermore, since it is up to the sender to choose the byte

size, some Hosts may choose a particular byte size (for simplicity and

convenience) and their NCP may not be geared to transmit in an imposed

byte size.

2. In RFCs 66 and 80, an ALL is expected on the connection to the server

socket before data can be sent. In RFCs 123 and 127 the ALL requirement

disappeared. But the ALL is a Host-Host protocol requirement and not

requiring it creates special case. A particular NCP implementation may

cause the ALL to be sent internally when a connection is created,

without the user process having control of it. Relaxing this requirement

will create a special case for the receiving NCP not to send the ALL and

for the sending NCP to send the data = S without first receiving an ALL.

3. In RF...