The MIB for providing information about Multi-layer Routing(MLR). This MIB will provide information used to control and measure SS7 messages signalling units in a SS7 Network. Message Signalling Units are routed based on information found in the SCCP, TCAP, MAP, and MAP-user layers. It uses information from these layers to make customizable routing decision based on the following criteria.

- message A-address (origination SME) - message B-address (destination SME) - protocol identifier - operation code - called party address - calling party address

The Cisco IP Transfer Point (ITP) is a hardware and software solution that transports SS7 traffic using IP. Each ITP node provides function similar to SS7 signalling point.

The Multi-layer SMS router will be developed in compliance to the following standards.

- GSM MAP v1, v2 and v3 MO SMS formats - GSM MAP SMS user information for MO messages - IS-41 MAP Mobile Originated SMS formats for Revisions A thru D.

Acronyms and Terms A-address The originating SME of the short message.

ANSI-41 ANSI standard for defining cellular radio telecommunications inter-system operation.

B-address The destination SME of the short message.

BCH Binary Coded Hexadecimal

CdPA The SCCP Called Party Address field.

CgPA The SCCP Calling Party Address field.

GSM ITU standard for defining the Global System for Mobile communications.

GTT Global Title Translation. A function normally performed in an STP, GTT is the procedure by which the destination signalling point and subsystem number(SSN) is determined from GTA digits (i.e., the global title) present in the signalling message.

IMEI International Mobile Equipment Identity

IMSI International Mobile Station Identity or International Mobile Subscriber Identity A mobile station identifier typically used in GSM networks, but is also defined for use in IS-41 networks via IS-751.

IS-41 ANSI standard for defining cellular radio telecommunications inter-system operation. Unless otherwise stated, this refers to the IS-41-D specification.

MAP SS7 Mobile Application Part. This layer provides mobility procedures to SS7 network applications. MAP is generically used to refer to both GSM-MAP, and the IS-41-D MAP Protocol.

MC Message Center. Network element responsible for relaying and store-and-forwarding of short messages in ANSI-41 networks.

MDN Mobile Directory Number. A 10-digit North American Numbering Plan number assigned to mobile users in IS-41 networks. It may be different from the MIN.

MIN Mobile Identification Number. The 10-digit North American Numbering Plan number assigned to mobile users in IS-41 networks. It may be different from the MDN.

MLR Multi-layer Routing

MO Mobile Originated. This term is used to refer to an SMS message that is being sent from an MS to the SMSC.

MS Mobile Subscriber.

MS mobile station

MSU Message Signal Unit

MT Mobile Terminated. This term is used to refer to an SMS message that is being sent from an SMSC to an MS.

MTP Message Transfer Part MTP1 Layers 1 (physical) MTP2 Layer 2 (data) and MTP3 Layer 3 (network)

M2PA SS7 MTP2-User Peer-to-Peer Adaptation Layer specified by the IETF SIGTRAN working group, which provides SCTP/IP based links for MTP3.

M3UA SS7 MTP3 User Adaptation Layer specified by RFC 3332 for MTP3 users like ISUP.

RR Round Robin. A balancing algorithm that evenly distributes traffic among available servers.

SCCP Signalling Connection Control Part. As part of the SS7 signalling protocol, it provides connectionless and connection-oriented network services above MTP Level 3.

SCP Service Control Point. An element of an SS7-based Intelligent Network which performs various service functions, such as number translation, call setup and tear down, etc.

SCTP Stream Control Transmission Protocol. A protocol designed by the SigTran working group of the IETF to transport messages reliably over IP networks(RFC 2960). It has been specifically designed with PSTN signalling in mind, but is meant to be a general IP transport protocol.

SG Signalling Gateway. SIM Subscriber Identity Module

SME Short Message Entity. An entity that may send or receive short messages, and may be fixed or mobile.

SM Short Message

SMD-PP Short Message Delivery Point to Point.

SMS Short Message Service, as defined in GSM and IS-41-D.

SMS-MO Short Message Service Mobile Originated.

SMS-MT Short Message Service Mobile Terminated.

SMSC Short Message Service Center. Network element responsible for relaying and store-and-forwarding of short messages.

SRI Send Routing Information or Send Routing Information for Short Messages. Refers to the procedure by which an SMSC requests the HLR to send current routing information for a particular mobile user.

SRI-SM Send Routing Information Short Message

SSP Service Switching Point. An element of an SS7-based Intelligent Network that performs call origination, termination, or tandem switching.

STP Signal Transfer Point. An element of an SS7-based Intelligent Network that performs routing of the SS7 signalling.

SUA SS7 SCCP User Adaptation Layer specified by IETF SIGTRAN for SCCP users, like GSM MAP, UMTS RANAP, CDMA IS-41, CDMA IS-634, IN INAP, CAMEL CAP.

TCAP Transaction Capability Application Part. The application layer of the SS7 signalling protocol.

WRR Weighted Round Robin. A variation of the round robin algorithm that uses server weights to allow uneven distribution of traffic among a set of available servers.

Multi-layer processing consists of four basic phases as follows.

Global Title Processing Trigger Processing(primary and secondary) Rule Set Processing Result group Processing

Example scenario.

The SMS messages sent by origin SME (typically a mobile handset) and sent to the MSC controlling the area in which the origin SME resides. The MSC then initiates a dialogue with the home SMSC specified by the origin SME to route the SMS MO message.

SMS MO traffic will arrive as an SCCP packet, and the Routing Indicator(RI) may specify either 'route-on-global-title' (RI=GT) or 'route-on-subsystem' (RI=PC/SSN). The destination GT will be used to locate the global title address that applies to the destination address.

Triggers are applied directly to global title addresses. Therefore, trigger processing consists of checking for the existence of primary trigger and then processing of secondary triggers.

If the message matches a trigger then rule set processing can be performed to determine what will be modified in message and how the message will be routed. The messages may be sent to new destination address, application server, point-code or result group. Or it could be forwarded without any modification (CONTINUE) or it could be dropped (BLOCK).

Result processing balances the delivery of messages to Point-codes or application servers based on Weighted Round Robin(WRR).

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