ÿWPCL ûÿ2BJ|xÐ ` ÐÐÌÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿH øÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿÌÐÐ °°°è ÐÑ Âx„|ü@Ž ÑÐ Å°6Ø'°6Ø'Å Ð G.7 ÓÓÃÃInterworking classÄÄ G.7.1 ÃÃCause No. 127 "interworking unspecified"ÄÄ Ð À ÐÁHÁThis cause indicates that there has been interworking with a network which does not provide causes for actions it takes, thus, the precise cause for a message which is being sent cannot be ascertained. ÁàÐJÁAnnex Hƒ ÁàÐMÁƒ ÁàÐAÁ(to Recommendation Q.931)ƒ ÁàÐMÁƒ ÁàÐ:ÁÃÃExamples of information elements codingÄă ÁHÁThis annex gives examples on the detailed coding of the following information elements: ÂHH©Âà  Âbearer capability information element;ÆÆ Ð ` Ð ÂHH©Âà  Âchannel identification information element;ÆÆ ÂHH©Âà  Âcalled/calling party sub©address.ÆÆ H.1ÂàHÂÃÃBearer capability information elementÄÄÆÆ H.1.1ÂðHÂÃÃCoding for speechÄÄÆÆ H.1.2ÂðHÂÃÃCoding for 3.1 kHz audioÄÄÆÆ H.1.3ÂðHÂÃÃCoding for unrestricted digital informationÄÄÆÆ ÃÃType 1ÄÄ: Synchronous 64 kbit/s working Ô ñ,ÔŒ Ð 8 ÐÃÃType 2ÄÄ: Synchronous rates less than 64 kbit/s with CCITT standardized rate adaption V.110/X.30; in©band negotiation not possible. H.1.4ÂðHÂÃÃCoding for X.25 packet mode access connectionsÄÄÆÆ ÃÃCase (b)ÄÄ H.2ÂàHÂÃÃChannel identification information elementÄÄÆÆ H.2.1ÂðHÂÃÃBasic interface, circuit mode, B channelÄÄÆÆ ÃÃExample (a)ÄÄ ÂHH©Âà  ÂChannel B1 preferred.ÆÆ Ð ` Ð Ð € ÐÂHH©Âà  ÂChannel is located in same interface which includes the D channel.ÆÆ Ð ` Ð ÃÃExample (b)ÄÄ ÂHH©Âà  ÂAny B channel.ÆÆ H.2.2ÂðHÂÃÃPrimary rate interface, circuit mode, B channelÄÄÆÆ ÃÃCase (a)ÄÄ Ô ñ,ÔŒ ÃÃCase (b)ÄÄ ÃÃExample (c)ÄÄ H.3ÂàHÂÃÃCalled/calling party sub©address information elementÄÄÆÆ H.3.1ÂðHÂÃÃCoding of IA5 sub©address digitsÄÄÆÆ Ð H ÐÃÃNote 1ÄÄ © AFI code 50 (in BCD) indicates that the sub©address consists of IA5 characters (see ISO standard 8348 AD2). ÃÃNote 2ÄÄ © IA5 character according to CCITT Recommendation T.50/ISO 646. Ð à ÐÃÃNote 3ÄÄ © The number of IA5 characters shown above is just an example. There may be up to 19 IA5 characters. ÃÃNote 4ÄÄ © The value of this bit has no significance when the type of sub©address is "NSAP". ÁàÀNÁAnnex Iƒ ÁàÀQÁƒ ÁàÀEÁ(to Recommendation Q.931)ƒ ÁàÀQÁƒ ÁàÀDÁÃÃUse of progress indicatorsÄă ÁHÁThis annex describes the use of the different progress indicator values defined in ÀÀ 4.5.22. Examples of use are given. ÁHÁÃÃProgress indicator No. 1ÄÄ indicates that interworking with a non©ISDN has occurred within the network or networks through which the call has traversed. ÁHÁÃÃProgress indicator No. 2ÄÄ indicates that the destination user is not ISDN. ÁHÁÃÃProgress indicator No. 3ÄÄ indicates that the origination user is not ISDN. ÁHÁÃÃProgress indicator No. 4ÄÄ indicates that a call which had left the ISDN has returned to the ISDN at the same point it had left due to redirection within the non©ISDN. This progress indicator would be employed when a prior Recommendation Q.931 message resulted in a progress indicator No. 1 "call is not end©to©end ISDN" being delivered to the calling user. ÁHÁThe use of progress indicators Nos. 1, 2 and 3 is exemplified in the following. ÁHÁThree interworking situations are identified in the figure below: ÂHHÂa)Âh   Âinterworking with another network;ÆÆ Ð ` Ð ÂHHÂb)Âh   Âinterworking with a non©ISDN user connected to ISDN;ÆÆ Ð Ð ÐÂHHÂc)Âh   Âinterworking with non©ISDN equipment within the calling or called user's premises.Ô ñ,ÔÆƌР` Ð ÁHÁAs regards calls from A the following applies: ÂHHÂcase a) © progress indicator No. 1 sent to A;ÆÆ ÂHHÂcase b) © progress indicator No. 2 sent to A;ÆÆ Ð ° ÐÂHHÂcase c) © progress indicator No. 2 sent to A (location sub©field =     private network).ÆÆ Ð ` Ð ÁHÁAs regards calls towards A the following applies: ÂHHÂcase a) © progress indicator No. 1 sent to A;ÆÆ ÂHHÂcase b) © progress indicator No. 3 sent to A;ÆÆ Ð ° ÐÂHHÂcase c) © progress indicator No. 3 sent to A (location sub©field =     private network)ÆÆ Ð ` Ð Ð X ÐÁHÁThe use of progress indicator No. 8 "in©band information or appropriate pattern now available" is described in ÀÀ 5. ÁàÀMÁAnnex Jƒ ÁàÀPÁƒ ÁàÀDÁ(to Recommendation Q.931)ƒ ÁàÀPÁƒ ÁàÀ5ÁÃÃExamples of cause value and location for busy conditionÄă ÁHÁThis annex gives examples on the detailed cause value and location to be sent in a Cause information element for the busy condition. ÁHÁFigure J©1/Q.931 shows the reference configuration which identifies nodes where busy condition may occur and therefore a cause should be generated. ÁHÁTable J©1/Q.931 shows: Ð Ð ÐÂHHÂa)Âh   Âa cause value and location to be generated at the point where the busy condition occurs; andÆÆ Ð ` Ð Ð Ð ÐÂHHÂb)Âh   Âa cause value and location to be delivered to the user (indicated as A) for each location (B © P) where the busy condition occurs.ÆÆ Ð ` Ð Ð Ð ÐAs is indicated in the table, the cause value is not changed but the location may be changed in the receiving exchange, when the cause value crosses a network boundary. ÃÃNoteÄÄ © The interface A©B, C©D, M©N and O©P are assumed to be Q.931. ÁàHGÁFIGURE J©1/Q.931ƒ ÁàHOÁƒ ÁàH3ÁÃÃExamples of cause values and location for busy conditionÄă ÁàHHÁTABLE J©1/Q.931ƒ ÁàHOÁƒ ÁàH7ÁÃÃLocation where busy occurs and the cause codingsÄă ÁàH2ÁÀ ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ Àƒ ÁàH4ÁÀ À  Location where À ÀCause at the pointÀ À  Cause received À Àƒ ÁàH3ÁÀ À   busy occurs À À of generation À À  by user A À Àƒ ÁàH2ÁÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀƒ ÁàH2ÁÀ À À À À À À Àƒ ÁàH5ÁÀ ÀB incoming circuit À À #34 or #44  LPN  À À ) À Àƒ ÁàH9ÁÀ ÀB outgoing circuit À À #34         LPN  À À ) À Àƒ ÁàH9ÁÀ ÀC outgoing circuit À À #34         LPN  À À ) À Àƒ ÁàH2ÁÀ À À À À À ) À Àƒ ÁàH6ÁÀ ÀD incoming circuit À À #34 or #44  LN   À À ) À Àƒ ÁàH9ÁÀ ÀD outgoing circuit À À #34         LN   À À )The same as leftÀ Àƒ ÁàH9ÁÀ ÀE outgoing circuit À À #34         LN   À À ) À Àƒ ÁàH2ÁÀ À À À À À ) À Àƒ ÁàH9ÁÀ ÀF outgoing circuit À À #34         TN   À À ) À Àƒ ÁàH9ÁÀ ÀG outgoing circuit À À #34         TN   À À ) À Àƒ ÁàH2ÁÀ À À À À À ) À Àƒ ÁàH8ÁÀ ÀH outgoing circuit À À #34         INTL À À ) À Àƒ ÁàH8ÁÀ ÀI outgoing circuit À À #34         INTL À À ) À Àƒ ÁàH2ÁÀ À À À À À À Àƒ ÁàH>ÁÀ ÀJ outgoing circuit À À #34         TN   À À #34         TN À Àƒ ÁàH>ÁÀ ÀK outgoing circuit À À #34         TN   À À #34         TN À Àƒ ÁàH2ÁÀ À À À À À À Àƒ ÁàH>ÁÀ ÀL outgoing circuit À À #34         LN   À À #34         RLN À Àƒ ÁàH>ÁÀ ÀM outgoing circuit À À #17         LN   À À #17         RLN À Àƒ ÁàH2ÁÀ À À À À À À Àƒ ÁàH4ÁÀ ÀN incoming circuit À À #34 or #44 LPN  À À #34 or #44 RPN À Àƒ ÁàH9ÁÀ ÀN outgoing circuit À À #34         LPN  À À #34 RPN À Àƒ ÁàH9ÁÀ ÀO outgoing circuit À À #17         LPN  À À #17 RPN À Àƒ ÁàH2ÁÀ À À À À À À Àƒ ÁàH4ÁÀ ÀP incoming circuit À À #34 or #44 U    À À #34 or #44 U À Àƒ ÁàH@ÁÀ ÀP call control     À À #17         U    À À #17         U À Àƒ ÁàH2ÁÀ ÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀÀ Àƒ ÁHÁLPN : Private network serving the local user ÁHÁLN : Public network serving the local user. ÁHÁTN : Transit network. ÁHÁINTL: International transit network. ÁHÁRLN : Public network serving the remote user. ÁHÁRPN : Private network serving the remote user. ÁHÁU : User. ÁHÁTable J©1/Q.931 is for further study. Ô ñ,ÔŒ ÁàHLÁAnnex Kƒ ÁàHOÁƒ ÁàHCÁ(to Recommendation Q.931)ƒ ÁàHOÁƒ ÁàH@ÁÃÃMessage segmentation proceduresÄă K.1ÂàHÂÃÃIntroductionÄÄÆÆ ÁHÁLayer 3 messages that are longer than the length of frames that the data link layer can support may be partitioned into several segments. ÁHÁMessage segmentation shall only be used when the message length exceeds N.201 (defined in Recommendation Q.921) [3]. These procedures are optional and may not be supported by all equipment. ÁHÁThe architectural relationship to other Recommendation Q.931 functions is shown in Figure K©1/Q.931. These procedures apply only within a specific data link connection and do not impact the procedures in operation on other parallel data link connections. K.2ÂàHÂÃÃMessage segmentationÄÄÆÆ ÁHÁThe following rules apply when Recommendation Q.931 messages are to be segmented for transmission: Ð À ÐÂHHÂa)Âh   Âthe default maximum number of message segments is eight. If the message is too long to be segmented then a local maintenance activity shall be notified;ÆÆ Ð ` Ð Ð € ÐÂHHÂb)Âh   Âthe first message segment shall begin with the protocol discriminator immediately followed by the Call reference, the segment message type, the Segmented message information element, and one or more other information elements;ÆÆ Ð ` Ð Ð ° ÐÂHHÂc)Âh   Âeach subsequent message segment shall begin with the protocol discriminator immediately followed by the call reference, the segment message type, the Segmented message information element and one or more other information elements;ÆÆ Ð ` Ð Ð  ÐÂHHÂd)Âh   Âthe first segment indicator field of the Segmented message information element shall be set to indicate the first segment of a segmented message, and not set in any other segment;ÆÆ Ð ` Ð Ð À ÐÂHHÂe)Âh   Âthe number of segments remaining field of the Segmented message information element shall be set to indicate how many more segments are to be sent, see Figure L©2/Q.931.ÆÆ Ð ` Ð Ð Ð ÐÂHHÂf)Âh   Âthe Message type information element shall be coded to indicate a segment message, and the Segmented message information element shall indicate the message type of the original message;ÆÆ Ð   ÐÂHHÂg)Âh   Âthe transmission of a segmented message may be aborted by: sending a message or message segment containing a different call reference; sending a message with the message type not coded "segment message" or stopping the transmission of subsequent message segments pertaining to the same message;ÆÆ Ð ` Ð Ð H ÐÂHHÂh)Âh   Âonce the first segment has been transmitted on a particular data link connection, then all remaining segments of that message shall be sent (in order) before any other message (segmented or not) for any other call reference is sent on that data link connection;ÆÆ Ð ` Ð Ð € ÐÂHHÂi)Âh   Âmessages shall be segmented only at information element boundaries; i.e., no information element shall be separated into two segments;ÆÆ Ð ` Ð Ð ° ÐÂHHÂj)Âh   Âthe information element order as a whole is preserved for the Segmented message regardless of segment boundary.ÆÆ Ð ` Ð K.3ÂàHÂÃÃReassembly of segmented messagesÄÄÆÆ Ð À ÐÁHÁThe following rules apply to the receipt and reassembly of segmented Q.931 messages: Ð H ÐÂHHÂa)Âh   Âa reassembly function, on receiving a message segment containing the Segmented message information element with the first segment indicator indicating "first message", and containing the call reference and message type (coded as "segment message" shall enter the Receiving Segmented Message state and accumulate message segments;ÆÆ Ð ` Ð Ð Ð ÐÂHHÂb)Âh   Âtimer T314, shall be initialized or reinitialized upon receipt of a message segment containing the Segmented message information element with a non©zero number of segments remaining field. Timer T314 shall be stopped upon receipt of the last segment; i.e., a message segment containing the segmented message information element with the number of segments remaining field coded zero. Timer T314 shall not be initialized or reinitialized if error procedures as identified in rules below are initiated;ÆÆ Ð ` Ð Ð  ÐÂHHÂc)Âh   Âa reassembly function receiving a message segment with a segmented message information element should wait for receipt of the last message segment pertaining to the same message i.e., containing the segmented message information element with the number of segments remaining field coded zero before delivering the message for further Q.931 processing as specified in ÀÀ 5.8. The reassembly function shall enter the Null state;ÆÆ Ð ` Ð Ð Ð ÐÂHHÂd)Âh   Âupon expiry of timer T314, the reassembly function shall: discard all segments of this message so far received; notify the layer 3 management entity for the data link connection that message segments have been lost; and enter the null state.ÆÆ Ð ` Ð Ð À ÐÂHHÂÂX  ÂÃÃNoteÄÄ © Subsequent message segments relating to the same message shall be discarded according to rule f).ÆÆ Ð À ÐÂHHÂe)Âh   Âa reassembly function, upon receiving eight message segments of the same segmented message without receiving a message segment with a number of segments remaining field of the Segmented message information element coded zero, shall: discard all message segments so far received;Ô ñ,Ô notify the layer 3 management entity for the data link connection that messages have been discarded; and enter the Null state;ÆÆ Ð ` Ð Ð À ÐÂHHÂÂX  ÂÃÃNoteÄÄ © Subsequent message segments relating to the same message shall be discarded according to rule f).ÆÆ Ð ` Ð Ð H ÐÂHHÂf)Âh   Âa reassembly function, on receiving a message segment containing a Segmented message information element, but with no call reference or Message type information element, while in the Null state shall discard that message segment and remain in the Null state;ÆÆ Ð ` Ð Ð H ÐÂHHÂg)Âh   Âa reassembly function, on receiving a message segment containing a Segmented message information element, while in the Receiving Segmented Message state with the number of segments remaining field that is not decremented from the number of segments remaining field in the Segmented message information element of the previous message segment, shall: discard all segments of this message so far received; and enter the Null state;ÆÆ Ð ` Ð Ð À ÐÂHHÂÂX  ÂÃÃNoteÄÄ © Subsequent message segments relating to the same message shall be discarded according to rule f).ÆÆ Ð ` Ð Ð ° ÐÂHHÂh)Âh   Âif there is a DLÃà ÄÄRELEASEÃà ÄÄINDICATION primitive or DLÃà ÄÄESTABLISH INDICATION primitive received while in the Receiving Segmented Message state, the reassembly function shall: discard all received message segments so far received; forward the DLÃà ÄÄÆÆ Ð Ð ÐÂHHÂÂX  ÂRELEASEÃà ÄÄINDICATION primitive or DLÃà ÄÄESTABLISHÃà ÄÄINDICATION primitive for further Q.931 processing, and enter the null state;ÆÆ Ð ` Ð Ð H ÐÂHHÂi)Âh   Âa reassembly function, upon receiving a message segment with the first segment indicator of the Segmented message information element indicating "subsequent", while in the Null state, shall: discard that message segment; and remain in the Null state.ÆÆ Ð ` Ð Áà9ÁFIGURE K©1/Q.931ƒ ÁàAÁƒ Áà'ÁÃÃLogical architecture containing segmentation functionÄă Ô ñ,ÔŒ Áà9ÁFIGURE K©2/Q.931ƒ ÁàAÁƒ Áà/ÁÃÃRelation between message and segmentsÄă ÃÃBlock diagramÄÄ Áà9ÁFIGURE K©3/Q.931ƒ ÁàAÁƒ Áà,ÁÃÃSegmentation functional interaction diagramÄă Áà9ÁFIGURE K©4/Q.931ƒ ÁàAÁƒ Áà7ÁÃÃMessage segmenter SDLÄă Áà9ÁFIGURE K©5/Q.931ƒ ÁàAÁƒ Áà1ÁÃÃMessage reassembler SDL (1 of 3)Äă Áà9ÁFIGURE K©5/Q.931ƒ ÁàAÁƒ Áà1ÁÃÃMessage reassembler SDL (2 of 3)Äă ÁàAÁƒ ÁàAÁƒ Áà9ÁFIGURE K©5/Q.931ƒ ÁàAÁƒ Áà1ÁÃÃMessage reassembler SDL (3 of 3)Äă