Service Indicator   Length   Transport Protocol/Service/Service Type

   Service Indicator   Length   Transport Protocol/Service/Service Type

   Address Indicator   Address Length   Address

     This response indicates no compatible application and/or transport
service available serving the destination.  For example, SMTP may be the
requested application service, while only NIFTP-mail is available
serving the destination.  Return with this command is the available
service of that type.  If no service available for that service type, a
empty text string is returned.

Examples:

   9  2
   3 14 TCP/NIFTP/mail
   3  0

   9  4
   3 13 TCP/NIFTP/RFT
   3 11 TCP/FTP/RFT
   2  6 "10  3  0  2  6 21"
   2  6 "39  0  0  5  6 21"

In the first example, the destination does not offer any kind of mail
service.  The second example indicates that there is no NIFTP, but FTP
available for remote file transfer service at the destination.


4.2.3 AIP/DNS Communication

     The source AIP presents its associated DNS with a fully qualified
domain specification for resolution.  The expected resolution result is
the network address for the destination endpoint DNS.  We assume no need
for communication between the DNS and AIP at the destination.

REQUEST

   Command Type   Number of Items

   Name Indicator   Name Length   Name String

Examples:

   1  1
   1 14 F.ISI.USC.ARPA

   1  1
   1 12 TSC.SRI.ARPA

                                   12
 
RFC 830                                                       October 1982



AFFIRMATIVE RESPONSE

   Command Type   Number of Items

   Name Indicator   Name Length    Name String

   Service Indicator   Service Length   Transport Protocol

   Address Indicator   Address Length   Address

Examples:

   2  3
   1 14 F.ISI.USC.ARPA
   3  3 UDP
   2  6 "10  2  0 52 17 42"

   2  4
   1  7 TSC.SRI.ARPA
   3  3 UDP
   2  6 "10  3  0  2 17 42"
   2  6 "39  0  0  5 17 42"

An affirmative response returns an address of the destination endpoint
DNS.  This returned address is that of the destination DNS.  The
destination transport service needs to be indicated for guiding the
parsing of the destination address.

NEGATIVE RESPONSE

   Command Type   Number of Items

   Name Indicator   Name Length   Name String

   Name Indicator   Name Length   Partial Name String

   [Comment Indicator  Comment Length   Comment]

     This response indicates that the domain name service is unable to
resolve the given destination domain name.  It could be caused by an
unknown simple name, which may result from, for example, misspelling.
Returned with this command is the left-most portion of the specified