[Docs] [txt|pdf] [Tracker] [Email] [Diff1] [Diff2] [Nits]

Versions: 00 01 02 03 RFC 2066

            Network Working Group                             R. Gellens
            INTERNET DRAFT                                        Unisys
                                                           July 24, 1996
                      Document:  draft-gellens-telnet-char-option-03.txt
                     Postscript:  draft-gellens-telnet-char-option-03.ps
            
            
            
            
            
                                TELNET CHARSET Option
            
            
            
            Status of this Memo
            
               This document is an Internet-Draft.  Internet-Drafts are
               working documents of the Internet Engineering Task Force
               (IETF), its areas, and its working groups.  Note that
               other groups may also distribute working documents as
               Internet-Drafts.
            
               Internet-Drafts are draft documents valid for a maximum
               of six months and may be updated, replaced, or obsoleted
               by other documents at any time.  It is inappropriate to
               use Internet-Drafts as reference material or to cite them
               other than as ``work in progress.''
            
               To learn the current status of any Internet-Draft, please
               check the ``1id-abstracts.txt'' listing contained in the
               Internet-Drafts Shadow Directories on ftp.is.co.za
               (Africa), nic.nordu.net (Europe), munnari.oz.au (Pacific
               Rim),     ds.internic.net (US East Coast), or ftp.isi.edu
               (US West Coast).
            
               A mailing list has been established for discussion of
               this (and related) topics.  To subscribe, send mail to:
                 telnet-request@mv.Unisys.com
            
            
            
            
            Gellens           Expires January 24, 1997          [Page 1]
            

            Internet Draft      TELNET CHARSET Option      July 24, 1996
            
            
            
            
            
               Items for redistribution to the list should be sent to:
                 telnet@mv.Unisys.com
            
            
            1.   Abstract
            
               This document specifies a mechanism for passing character
               set and translation information between a TELNET client
               and server.  Use of this mechanism enables an application
               used by a TELNET user to send and receive data in the
               correct character set.
            
               Either side can (subject to option negotiation) at any
               time request that a (new) character set be used.
            
            
            
            2.   Command Names and Codes
            
               CHARSET.......................xx
            
                 REQUEST ....................01
                 ACCEPTED ...................02
                 REJECTED ...................03
                 TTABLE-IS ..................04
                 TTABLE-REJECTED ............05
                 TTABLE-ACK .................06
                 TTABLE-NAK .................07
            
            
            As a convenience, standard TELNET text and codes for
            commands used in this document are reproduced here
            (excerpted from [1]):
            
            
               All TELNET commands consist of at least a two byte
               sequence:  the "Interpret as Command" (IAC) escape
               character followed by the code for the command.  The
               commands dealing with option negotiation are three byte
               sequences, the third byte being the code for the option
               referenced. ... [O]nly the IAC need be doubled to be sent
               as data, and the other 255 codes may be passed
            
            
            
            Gellens           Expires January 24, 1997          [Page 2]
            

            Internet Draft      TELNET CHARSET Option      July 24, 1996
            
            
            
            
            
               transparently.  The following are [some of] the defined
               TELNET commands.  Note that these codes and code
               sequences have the indicated meaning only when
               immediately preceded by an IAC.
            
            
                 NAME          CODE  MEANING
            
                 SE             240  End of subnegotiation parameters.
            
                 SB                  Indicates that what follows is
                                250
                                     subnegotiation of the indicated
                                     option.
            
                 WILL (option   251  Indicates the desire to begin
                 code)               performing, or confirmation that
                                     you are now performing, the
                                     indicated option.
            
                 WON'T          252  Indicates the refusal to perform,
                 (option             or continue performing, the
                 code)               indicated option.
            
                 DO (option     253  Indicates the request that the
                 code)               other party perform, or
                                     confirmation that you are expecting
                                     the other party to perform, the
                                     indicated option.
            
                 DON'T          254  Indicates the demand that the other
                 (option             party stop performing, or
                 code)               confirmation that you are no longer
                                     expecting the other party to
                                     perform, the indicated option.
            
                 IAC            255  Data Byte 255.
            
            
            
            
            
            
            
            
            
            Gellens           Expires January 24, 1997          [Page 3]
            

            Internet Draft      TELNET CHARSET Option      July 24, 1996
            
            
            
            
            
            3.   Command Meanings
            
            A very simple meta-syntax is used, where most tokens
            represent previously defined items (such as IAC); angle-
            brackets (``<>``) are used for items to be further defined;
            curly-braces (``{}'') are used around optional items;
            ellipses represent repeated sequences of items; and quotes
            are used for literal strings.
            
            
            IAC WILL CHARSET
               The sender REQUESTS permission to, or AGREES to, use
               CHARSET option subnegotiation to choose a character set.
            
            
            IAC WON'T CHARSET
               The sender REFUSES to use CHARSET option subnegotiation
               to choose a character set.
            
            
            IAC DO CHARSET
               The sender REQUESTS that, or AGREES to have, the other
               side use CHARSET option subnegotiation to choose a
               character set.
            
            
            IAC DON'T CHARSET
               The sender DEMANDS that the other side not use the
               CHARSET option subnegotiation.
            
            
            IAC SB CHARSET REQUEST { ``[TTABLE]'' <Version> } <char set
            list> IAC SE
            
               Char set list:
            
               <sep> <character set> { ...<sep> <character set> }
            
               This message initiates a new CHARSET subnegotiation.  It
               can only be sent by a side that has received a DO CHARSET
               message and sent a WILL CHARSET message (in either
               order).
            
            
            
            Gellens           Expires January 24, 1997          [Page 4]
            

            Internet Draft      TELNET CHARSET Option      July 24, 1996
            
            
            
            
            
               The sender requests that all text sent to and by it be
               encoded in one of the specified character sets.
            
               If the string [TTABLE] appears, the sender is willing to
               accept a mapping (translation table) between any
               character set listed in <char set list> and any character
               set desired by the receiver.
            
               <Version>  is an octet whose binary value is the highest
               version level of the TTABLE-IS message which can be sent
               in response.  This field must not be zero.  See the
               TTABLE-IS message for the permitted version values.
            
               <Char set list>  is a sequence of 7-BIT ASCII printable
               characters.  The first octet defines the separator
               character (which must not appear within any character
               set).  It is terminated by the IAC SE sequence.  Case is
               not significant.  It consists of one or more character
               sets.  The character sets should appear in order of
               preference (most preferred first).
            
               <Sep>  is a separator octet, the value of which is chosen
               by the sender.  Examples include a space or a semicolon.
               Any value other than IAC is allowed.  The obvious choice
               is a space or any other punctuation symbol which does not
               appear in any of the character set names.
            
               <Character set>  is a sequence of 7-BIT ASCII printable
               characters.  Case is not significant.
            
               If a requested character set is registered with the
               Internet Assigned Number Authority (IANA) [2], it is
               required that the standardized spelling of its name or a
               registered alias be used.  While it is permitted to
               request non-standard character sets such as those not
               registered with IANA, this is strongly discouraged, as
               such character sets are unlikely to be recognized by the
               receiver of the CHARSET REQUEST message.  Even worse, a
               non-registered character set could have the same name as
               some other character set which is registered.  Each side
               would then be using a character set different from that
               expected by the other.
            
            
            
            Gellens           Expires January 24, 1997          [Page 5]
            

            Internet Draft      TELNET CHARSET Option      July 24, 1996
            
            
            
            
            
               The receiver responds in one of four ways:
            
                 If the receiver is already sending text to and
                 expecting text from the sender to be encoded in one of
                 the specified character sets, it sends a positive
                 acknowledgment (CHARSET ACCEPTED); it MUST NOT ignore
                 the message.  (Although ignoring the message is perhaps
                 suggested by some interpretations of the relevant RFCs
                 ([1], [3]), in the interests of determinacy it is not
                 permitted.  This ensures that the issuer does not need
                 to time out and infer a response, while avoiding
                 (because there is no response to a positive
                 acknowledgment) the non-terminating subnegotiation
                 which is the rationale in the RFCs for the non-response
                 behavior.)
            
                 If the receiver is capable of handling at least one of
                 the specified character sets, it can respond with a
                 positive acknowledgment for one of the requested
                 character sets.  Normally, it should pick the first set
                 it is capable of handling but may choose one based on
                 its own preferences.  After doing so, each side MUST
                 encode subsequent text in the specified character set.
            
                 If the string [TTABLE] is present, and the receiver
                 prefers to use a character set not included in <char
                 set list>, and is capable of doing so, it can send a
                 translate table (TTABLE-IS) response.
            
                 If the receiver is not capable of handling any of the
                 specified character sets, it sends a negative
                 acknowledgment (CHARSET REJECTED).
            
               Because it is not valid to reply to a CHARSET REQUEST
               message with another CHARSET REQUEST message, if a
               CHARSET REQUEST message is received after sending one, it
               means that both sides have sent them simultaneously.  In
               this case, the server side MUST issue a negative
               acknowledgment.  The client side MUST respond to the one
               from the server.
            
            
            
            
            
            Gellens           Expires January 24, 1997          [Page 6]
            

            Internet Draft      TELNET CHARSET Option      July 24, 1996
            
            
            
            
            
            IAC SB CHARSET ACCEPTED <Charset> IAC SE
               This is a positive acknowledgment response to a CHARSET
               REQUEST message; the receiver of the CHARSET REQUEST
               message acknowledges its receipt and accepts the
               indicated character set.
            
               <Charset> is a character sequence identical to one of the
               character sets in the CHARSET REQUEST message.  It is
               terminated by the IAC SE sequence.
            
               Text messages which follow this response must now be
               coded in the indicated character set.  This message
               terminates the current CHARSET subnegotiation.
            
            
            IAC SB CHARSET REJECTED IAC SE
               This is a negative acknowledgment response to a CHARSET
               REQUEST message; the receiver of the CHARSET REQUEST
               message acknowledges its receipt but refuses to use any
               of the requested character sets.  Messages can not be
               sent in any of the indicated character sets.  This
               message can also be sent by the sender of a TTABLE-IS
               message, if multiple TTABLE-NAK messages were sent in
               response.  This message terminates the current CHARSET
               subnegotiation.
            
            
            IAC SB CHARSET TTABLE-IS <version> <syntax for version> IAC
            SE
               In response to a CHARSET REQUEST message in which
               [TTABLE] was specified, the receiver of the CHARSET
               REQUEST message acknowledges its receipt and is
               transmitting a pair of tables which define the mapping
               between specified character sets.
            
               <Version> is an octet whose binary value is the version
               level of this TTABLE-IS message.  Different versions have
               different syntax.  The lowest version level is one (zero
               is not valid).  The current highest version level is also
               one.  This field is provided so that future versions of
               the TTABLE-SEND message can be specified, for example, to
               handle character sets for which there is no simple one-
            
            
            
            Gellens           Expires January 24, 1997          [Page 7]
            

            Internet Draft      TELNET CHARSET Option      July 24, 1996
            
            
            
            
            
               to-one character-for-character translation.  This might
               include some forms of multi-octet character sets for
               which translation algorithms or subsets need to be sent.
            
               Syntax for Version 1:
            
               <sep> <char set name 1> <sep> <char size 1> <char count
               1> <char set name 2> <sep> <char size 2> <char count 2>
               <map 1> <map 2>
            
               <Sep>  is a separator octet, the value of which is chosen
               by the sender.  Examples include a space or a semicolon.
               Any value other than IAC is allowed.  The obvious choice
               is a space or any other punctuation symbol which does not
               appear in either of the character set names.
            
               <Char set name 1> and <Char set name 2>  are sequences of
               7-BIT ASCII printable characters which identify the two
               character sets for which a mapping is being specified.
               Each is terminated by <sep>.  Case is not significant.
               If a character set is registered with IANA, it is
               required that the standardized spelling of its name or a
               registered alias be used.  <Char set name 1> should be
               chosen from the <char set list> in the CHARSET REQUEST
               message.  <Char set name 2> can be arbitrarily chosen.
               Text on the wire should be encoded using <char set name
               2>.
            
               <Char size 1>  and <char size 2>  are single octets each.
               The binary value of the  octet is the number of bits
               nominally required for each character in the
               corresponding table.  It should be a multiple of eight.
            
               <Char count 1> and <char count 2>  are each three-octet
               binary fields in Network Byte Order [6].  Each specifies
               how many characters (of the maximum 2**<char size>) are
               being transmitted in the corresponding map.
            
            
            
            
            
            
            
            
            Gellens           Expires January 24, 1997          [Page 8]
            

            Internet Draft      TELNET CHARSET Option      July 24, 1996
            
            
            
            
            
               <Map1> and <Map 2>  each consist of the corresponding
               <char count> number of characters.  These characters form
               a mapping from all or part of the characters in one of
               the specified character sets to the correct characters in
               the other character set.  If the indicated <char count>
               is less than  2**<char size>, the first <char count>
               characters are being mapped, and the remaining characters
               are assumed to not be changed (and thus map to
               themselves).  That is, each map contains characters 0
               through <char count> -1.  <Map 1> maps from <char set
               name 1> to <char set name 2>.  <Map 2> maps from <char
               set name 2> to <char set name 1>.  Translation between
               the character sets is thus an obvious process of using
               the binary value of a character as an index into the
               appropriate map.  The character at that index replaces
               the original character.  If the index exceeds the <char
               count> for the map, no translation is performed for the
               character.
            
               [Note to implementers: since TELNET works in octets, it
               is possible for octets of value 255 to appear
               ``spontaneously'' when using multi-octet or non-8-bit
               characters.  All octets of value 255 (other than IAC)
               MUST be quoted to conform with TELNET requirements.  This
               applies even to octets within a table, or text in a
               multi-octet character set.]
            
            
            IAC SB CHARSET TTABLE-ACK IAC SE
               The sender acknowledges the successful receipt of the
               translate table.  Text messages which follow this
               response must now be coded in the character set specified
               as <char set name 2> of the TTABLE-IS message.  This
               message terminates the current CHARSET subnegotiation.
            
            
            IAC SB CHARSET TTABLE-NAK IAC SE
               The sender reports the unsuccessful receipt of the
               translate table and requests that it be resent.  If
               subsequent transmission attempts also fail, a TTABLE-
               REJECTED or CHARSET REJECTED message (depending on which
            
            
            
            
            Gellens           Expires January 24, 1997          [Page 9]
            

            Internet Draft      TELNET CHARSET Option      July 24, 1996
            
            
            
            
            
               side sends it) should be sent instead of additional
               futile TTABLE-IS and TTABLE-NAK messages.
            
            IAC SB CHARSET TTABLE-REJECTED IAC SE
               In response to a TTABLE-IS message, the receiver of the
               TTABLE-IS message acknowledges its receipt and indicates
               it is unable to handle it.  This message terminates the
            
            
            
            Any system which supports the CHARSET option MUST fully
            support the CHARSET REQUEST, ACCEPTED, REJECTED, and TTABLE-
            REJECTED subnegotiation messages.  It MAY optionally fully
            support the TTABLE-IS, TTABLE-ACK, and TTABLE-NAK messages.
            If it does fully support the TTABLE-IS message, it MUST also
            fully support the TTABLE-ACK and TTABLE-NAK messages.
            
            
            
            4.   Default
            
            
               WON'T CHARSET
            
               DON'T CHARSET
            
            
            5.   Motivation for the Option
            
               Many TELNET sessions need to transmit data which is not
               in 7-bit ASCII.  This is usually done by negotiating
               BINARY, and using local conventions (or terminal type
               kluges) to determine the character set of the data.
               However, such methods tend not to interoperate well, and
               have difficulties when multiple character sets need to be
               supported by different sessions.
            
               Many computer systems now utilize a variety of character
               sets.  Increasingly, a server computer needs to document
               character sets or translate transmissions and receptions
               using different pairs of character sets on a per-
            
            
            
            
            
            Gellens           Expires January 24, 1997         [Page 10]
            

            Internet Draft      TELNET CHARSET Option      July 24, 1996
            
            
            
            
            
               application or per-connection basis.  This is becoming
               more common as client and server computers become more
               geographically disperse.  (And as servers are
               consolidated into ever-larger hubs, serving ever-wider
               areas.)  In order for files, databases, etc. to contain
               correct data, the server must determine the character set
               in which the user is sending, and the character set in
               which the application expects to receive.
            
               In some cases, it is sufficient to determine the
               character set of the end user (because every application
               on the server expects to use the same character set, or
               because applications can handle the user's character
               set), but in other cases different server applications
               expect to use different character sets.  In the former
               case, an initial CHARSET subnegotiation suffices.  In the
               latter case, the server may need to initiate additional
               CHARSET subnegotiations as the user switches between
               applications.
            
               At a minimum, the option described in this memo allows
               both sides to be clear as to which character set is being
               used.  A minimal implementation would have the server
               send DO CHARSET, and the client send WILL CHARSET and
               CHARSET REQUEST.  The server could then communicate the
               client's character set to applications using whatever
               means are appropriate.  Such a server might refuse
               subsequent CHARSET REQUEST messages from the client (if
               it lacked the ability to communicate changed character
               set information to applications, for example).  Another
               system might have a method whereby various applications
               could communicate to the TELNET server their character
               set needs and abilities, which the server would handle by
               initiating new CHARSET REQUEST negotiations as
               appropriate.
            
               In some cases, servers may have a large set of clients
               which tend to connect often (such as daily) and over a
               long period of time (such as years).  The server
               administrators may strongly prefer that the servers not
               do character set translation (to save CPU cycles when
               serving very large numbers of users).  To avoid manually
            
            
            
            Gellens           Expires January 24, 1997         [Page 11]
            

            Internet Draft      TELNET CHARSET Option      July 24, 1996
            
            
            
            
            
               configuring each copy of the user TELNET software, the
               administrators might prefer that the software supports
               translate tables.  (If the client software received a
               translate table from the server and stored it, the table
               would only need to be sent once.)
            
            
            6.   Description of the Option
            
               When the client TELNET program is able to determine the
               user's character set it should offer to specify the
               character set by sending IAC WILL CHARSET.
            
               If the server system is able to make use of this
               information, it replies with IAC DO CHARSET.  The client
               TELNET is then free to request a character set in a
               subnegotiation at any time.
            
               Likewise, when the server is able to determine the
               expected character set(s) of the user's application(s),
               it should send  IAC DO CHARSET to request that the client
               system specify the character set it is using.  Or the
               server could send IAC WILL CHARSET to offer to specify
               the character sets.
            
               Once a character set has been determined, the server can
               either perform the translation between the user and
               application character sets itself, or request by
               additional CHARSET subnegotiations that the client system
               do so.
            
               Once it has been established that both sides are capable
               of character set negotiation (that is, each side has
               received either a WILL CHARSET or a DO CHARSET message,
               and has also sent either a DO CHARSET or a WILL CHARSET
               message), subnegotiations can be requested at any time by
               whichever side has sent a WILL CHARSET message and also
               received a DO CHARSET message (this may be either or both
               sides).  Once a CHARSET subnegotiation has started, it
               must be completed before additional CHARSET
               subnegotiations can be started (there must never be more
               than one CHARSET subnegotiation active at any given
            
            
            
            Gellens           Expires January 24, 1997         [Page 12]
            

            Internet Draft      TELNET CHARSET Option      July 24, 1996
            
            
            
            
            
               time).  When a subnegotiation has completed, additional
               subnegotiations can be started at any time.
            
               If either side violates this rule and attempts to start a
               CHARSET subnegotiation while one is already active, the
               other side MUST reject the new subnegotiation by sending
               a CHARSET REJECTED message.
            
               Receipt of a CHARSET REJECTED or TTABLE-REJECTED message
               terminates the subnegotiation, leaving the character set
               unchanged.  Receipt of a CHARSET ACCEPTED or TTABLE-ACK
               message terminates the subnegotiation, with the new
               character set in force.
            
               In some cases, both the server and the client systems are
               able to perform translations and to send and receive in
               the character set(s) expected by the other side.  In such
               cases, either side can request that the other use the
               character set it prefers.  When both sides simultaneously
               make such a request (send CHARSET REQUEST messages), the
               server MUST reject the client's request by sending a
               CHARSET REJECTED message.  The client system MUST respond
               to the server's request.  (See the CHARSET REQUEST
               description, above.)
            
               When the client system makes the request first, and the
               server is able to handle the requested character set(s),
               but prefers that the client system instead use the
               server's (user application) character set, it may reject
               the request, and issue a CHARSET REQUEST of its own.  If
               the client system is unable to comply with the server's
               preference and issues a CHARSET REJECTED message, the
               server can issue a new CHARSET REQUEST message for one of
               the previous character sets (one of those which the
               client system originally requested).  The client system
               would obviously accept this character set.
            
               While a CHARSET subnegotiation is in progress, data
               should be queued.  Once the CHARSET subnegotiation has
               terminated, the data can be sent (in the correct
               character set).
            
            
            
            
            Gellens           Expires January 24, 1997         [Page 13]
            

            Internet Draft      TELNET CHARSET Option      July 24, 1996
            
            
            
            
            
               Note that regardless of CHARSET negotiation, translation
               only applies to text (not commands), and only occurs when
               in BINARY mode [4].  If not in BINARY mode, all data is
               assumed to be in NVT ASCII [1].
            
               Also note that the CHARSET option should be used with the
               END OF RECORD option [5] for block-mode terminals in
               order to be clear on what character represents the end of
               each record.
            
               As an example of character set negotiation, consider a
               user on a workstation using TELNET to communicate with a
               server.  In this example, the workstation normally uses
               the Cyrillic (ASCII) character set [2] but is capable of
               using EBCDIC-Cyrillic [2], and the server normally uses
               EBCDIC-Cyrillic.  The server could handle the (ASCII)
               Cyrillic character set, but prefers that instead the
               client system uses the EBCDIC-Cyrillic character set.
               (This and the following examples do not show the full
               syntax of the subnegotiation messages.)
            
                    CLIENT                        SERVER
            
                 WILL CHARSET                   WILL CHARSET
            
                 DO CHARSET                     DO CHARSET
            
                 CHARSET REQUEST Cyrillic
                    EBCDIC-Cyrillic
            
                                                CHARSET ACCEPTED EBCDIC-
                                                  Cyrillic
            
            
            
               Now consider a case where the workstation can't handle
               EBCDIC-Cyrillic, but can accept a translate table:
            
                    CLIENT                        SERVER
            
                 WILL CHARSET                   WILL CHARSET
            
            
            
            
            Gellens           Expires January 24, 1997         [Page 14]
            

            Internet Draft      TELNET CHARSET Option      July 24, 1996
            
            
            
            
            
                 DO CHARSET                     DO CHARSET
            
                 CHARSET REQUEST [TTABLE] 1
                    Cyrillic
            
                                                CHARSET TTABLE-IS 1 Cyrillic
                                                  EBCDIC-Cyrillic
            
                 CHARSET TTABLE-ACK
            
            
            
               For another example, consider a case similar to the
               previous case, but now the user switches server
               applications in the middle of the session (denoted by
               ellipses), and the new application requires a different
               character set:
            
                    CLIENT                        SERVER
            
                 WILL CHARSET                   WILL CHARSET
            
                 DO CHARSET                     DO CHARSET
            
                 CHARSET REQUEST [TTABLE] 1
                    Cyrillic EBCDIC-INT
            
                                                CHARSET TTABLE-IS 1 Cyrillic
                                                  EBCDIC-Cyrillic
            
                 CHARSET TTABLE-ACK
            
                 . . .                          . . .
            
                                                CHARSET REQUEST EBCDIC-INT
            
                 CHARSET ACCEPTED EBCDIC-INT
            
            
            
            
            
            
            
            
            Gellens           Expires January 24, 1997         [Page 15]
            

            Internet Draft      TELNET CHARSET Option      July 24, 1996
            
            
            
            
            
            7.   Security Considerations
            
               This document raises no security issues.
            
            
            8.   References
            
               [1]Postel, J. and Reynolds, J., ``Telnet Protocol
                  Specification'', STD 8, RFC 854, ISI, May 1983
            
               [2]Reynolds, J., and Postel, J., ``Assigned Numbers'',
                  STD 2, RFC 1700, ISI, October 1994
            
               [3]Postel, J. and Reynolds, J., ``Telnet Option
                  Specifications'', STD 8, RFC 855, ISI, May 1983
            
               [4]Postel, J. and Reynolds, J., 11Telnet Binary
                  Transmission'', RFC 856, ISI, May 1983
            
               [5]Postel, J., ``Telnet End-Of-Record Option'', RFC 885,
                  ISI, December 1983
            
               [6]Postel, J., ``Internet Official Protocol Standards'',
                  STD 1, RFC 1780, IAB, March 1995
            
            
            
            9.   Author's Address
            
               Randall C. Gellens
               Unisys Corporation
               25725 Jeronimo Road
               Mail Stop 237
               Mission Viejo, CA  92691
               USA
            
               Phone:  +1.714.380.6350
               Fax:    +1.714.380.5912
            
               Randy@MV.Unisys.Com
            
            
            
            
            
            Gellens           Expires January 24, 1997         [Page 16]
            

Html markup produced by rfcmarkup 1.109, available from https://tools.ietf.org/tools/rfcmarkup/