ISDN Protocol Administrator's and Developer's Guide ... - Intervoice

DPNSS 1 OverviewTable 6-1. DPNSS 1 Network Layer Messages (continued)Symbol Message Type DescriptionISRM(I)LLM(C)LLM(I)LLRMLMMLMRMNAMNIMNSIMRM(C)RM(I)Initial Service RequestMessage (Incomplete)Link-by-Link Message(Complete)Link-by-Link Message(Incomplete)Link-by-Link RejectMessageLink MaintenanceMessageLink Maintenance RejectMessageNumber AcknowledgeMessageNetwork IndicationMessageNon SpecifiedInformation MessageRecall Message(Complete)Recall Message(Incomplete)Used under the following conditions:• The 45 octets of an ISRM(C) are not enough to hold the selectioninformation and the Destination Address.• The Destination Address digits are sent to a slower-speed signalingsystem.• The end of dialing cannot be determined by the originating PBX.This message is normally followed by at least one SSRM messagecontaining further selection information.Carries information between adjacent PBXs.It also indicates the completion of a link-by-link sequence which wasstarted with an LLM(I).Used when the 45 octets of an LLM(C) are not enough to hold thenecessary information.The sequence started by an LLM(I) will be completed by an LLM(C)unless the call is cleared beforehand.Rejects an unrecognized or invalid message in an LLM messagegroup.Requests or responds to a request for maintenance actions.Responds to a request for maintenance when the request is rejected.Sent for successful simple calls within DPNSS 1. This message is alsoused to indicate that all digits have been received in certaininterworking situations.Subsequent messages containing additional information will follow.Used only during the routing phase of a call to notify PBXs along theroute of its progress.The message can be used only in the backward direction and cannot beused after a NAM.Carries non-DPNSS 1-defined information between end PBXs.This message is used by some supplementary services to establish asecond call by the same channel as an existing call.It contains the complete call request.Used by some supplementary services to establish a second call by thesame channel as an existing call.Can be used in place of an RM(C), and is normally followed by at leastone SSRM containing further selection information,RRM Recall Rejection Message Indicates that a Recall Request has not succeeded.60001262, First Edition DPNSS 1 Protocol 6-3