RFC40

Network Working Group E. Harslem Request for Comments: 40 J. Heafner

                                                                RAND
                                                          March 1970

           More Comments on the Forthcoming Protocol

We have recently discussed NWG/RFC Nos. 36 and 39 with Steve Crocker, UCLA. Steve has asked that we elaborate on the errors, queries, and HOST status that were mentioned in NWG/RFC #39.

Please voice your opinions soon in order to affect the forthcoming protocol specifications.

ERROR MESSAGES

 <ERR>  <Command length> <Command in error>

is an eight-bit field that specifies the error type. The assigned codes are shown below. <Command length> is a 16-bit integer that indicates the length of the <Command in error> in bits. The <Command in error> is the spurious command.

The ranges of are shown below in hexidecimal.

 00     Unspecified error types
 10-0F  Resource errors
 10-1F  Status errors
 20-2F  Content errors
 30-3F  Unused

Specific values of are shown below with their meaning.

  value   Semantics

     00         Unspecified errors.
     01         Request for an invalid resource.
     02         Request for an exhausted resource, try later.
    03-0F       Unused.
     10         Invalid <RSM>, i.e., link connected but unblocked.
     11         Invalid <SPD>.
     12         Invalid <ASG>, i.e., connected but no <RDY>
                  received.

  value   Semantics

     13         Message received on blocked link.
    14-1F       Unused.
     20         Unknown command code.
     21         Message received on unconnected link.
     22         Invalid <RFC>.
     23         Invalid <CLS>.
     24         Invalid <RSM>, i.e., link not connected.
     25         Invalid <FND>.
     26         Invalid <END>.
     27         Invalid <RDY>.
     28         Invalid <ASG>, i.e., not connected.
    29-2F       Unused.
    30-FF       Unused.

QUERIES

 <QRY> <My Socket>

or <RPY> <Your Socket> <Text>

The <QRY> is the query indicated in NWG/RFC #39 and <RPY> is the reply. The format of <Text> is shown below; also refer to NWG/RFC #36, p. 3.

<Text>::= <16 bit count of relevant connection table entries>

      <relevant connection table entries>

<relevant connection table entries>::=

                                 <relevant connection table entries>
                                 <a relevant connection table entry>
                                 <a relevant connection table entry>

<a relevant connection table entry>::= <local socket> <foreign socket>

                                   <link> <connection state>
                                   <flow state and buffer control>
                                   <reconnection control state>

HOST STATUS

 <NOP>

An NCP may be up, down, pending, etc. When an NCP changes its state to UP it should send a <NOP> to each remote NCP which indicates the NCP is available. The sending NCP can then construct a vector of HOST status from the RFNMs it receives. An NCP receiving a <NOP> can update the availability of the sending NCP in its HOST status vector.

   [ This RFC was put into machine readable form for entry ]
     [ into the online RFC archives by Richard Ames 6/97 ]