CISCO-ITP-RT-MIB

This MIB is for managing information required to route messages transported over Signalling System No. 7 (SS7) Network via Cisco IP Transfer Point. The Cisco IP Transfer Point (ITP) is a hardware and software solution that transports SS7 traffic using IP. Each ITP node provides the functions necessary to act as a SS7 signalling point. Each signalling point is connected to other signalling point using IP based or traditional TDM links. The relevant ITU documents describing this technology are the ITU Q series, including ITU Q.700: Introduction to CCITT Signalling System No. 7 and ITU Q.701 Functional description of the message transfer part (MTP) of Signalling System No. 7. Definitions and overview: Route: A route consists of one or more linksets used to transport MTP3 Message Signal Units(MSU) between signalling points. A route is an association between a destination point code(DPC) and a linkset, i.e., a linkset that can be used to send an MSU to the given DPC. Routeset: A routeset is a set of routes to a given DPC. Each route within a routeset is on a possible path toward the DPC. Each route within the routeset has associated with it a route priority. In the following simple configuration, two routes exist that can be used to transport MSUs from STP1 to STP4. --------- STP1-STP2 --------- - STP1 ----------------------------- STP2 - --------- --------- | | | STP1-STP3 STP2-STP4 | | | --------- STP3-STP4 --------- - STP3 ----------------------------- STP4 - --------- --------- Routeset on STP1 for DPC = STP4: STP1-STP2, STP1-STP3 Linkset: A linkset is a set of signalling links connecting two signalling points. Combined Linkset: Two linksets with equal number of links and capacity that form routes of equal priority to a given DPC are called Combined Linksets. It is primarily used for load sharing and redundancy. In the following, example, linksets 'SSP1-STP1' and 'SSP1-STP2' form a combined linsket. SSP1-STP1 --------- |------------------------- STP1 - | --------- - - - - - SSP1 - - - - - | SSP1-STP2 --------- |------------------------ STP2 - --------- Routing: The routing of SS7 Message signalling Units(MSU) is based on the DPC. Message Signalling Units are sent from an originating point code(OPC) to DPC. Each MSU will traverse one or more linksets as it is routed to its final destination. When an MSU arrives at a signalling point and the DPC does not match the signalling point's point code the MSU must be directed toward the DPC. Each signalling point has enough routing information to determine which linkset should be used to transmit the MSU toward its final destination. Route statement: Each ITP Signalling Point has route statements needed to determine which linkset should be used to transmit message signalling units to destinations. Each route statement consists of a destination, a priority and a linkset name. The destination is specified as a combination of DPC and mask. The priority, also know as cost, is used to define the order in which the routes are selected. The linkset name specifies which linkset to use to reach the destination. Route table: Each ITP Signalling Point has a table of routes. These route entries are used to determine which linkset should be selected to transmit message signalling units to a given destination. There are two basic type of routing. The first type is fully-qualified and uses all bits of the target DPC. The other type is summary routing that uses a subset of the bits in the target DPC and is used to represent groups of point codes rather than a single point code. Example of route table entries. Example 1: variant = ITU DPC/MASK Priority Linkset-name -------- -------- ----------------------- 5.5.5/14 3 STP1-STP2 5.5.5/14 7 STP1-STP3 Description: Two route table entries that define a primary route using linkset 'STP1-STP2' and an alternate route using linkset 'STP1-STP3' to point-code 5.5.5. Example 2: variant = ITU DPC/MASK Priority Linkset-name -------- -------- ----------------------- 5.5.5/14 3 STP1-STP2 5.5.5/14 3 STP1-STP3 5.5.5/14 7 STP1-STP4 Description: Two route table entrys that define a combined linkset consisting of linkset 'STP1-STP2' and 'STP1-STP3' to point code 5.5.5. An alternate route is also defined using linkset 'STP1-STP4'. Example 3: variant = ANSI DPC/MASK Priority Linkset-name -------- -------- ----------------------- 5.5.0/16 3 STP1-STP2 Description: A route table entry that defines routing to a cluster. The cluster represents all point codes in the range from 5.5.0-5.5.255. Example 4: variant = ANSI DPC/MASK Priority Linkset-name -------- -------- ----------------------- 5.5.0/16 3 STP1-STP3 5.5.5/24 3 STP1-STP2 Description: The mixing of fully-qualified and summary route table entrys allow for different routes to be defined for certain DPC in a cluster. In this configuration, the fully-qualified route will be the primary and the summary route will act as a backup. Route table: A group of route table entrys used to route MSU for a particular instance of a signalling point. A sample route table. DPC/MASK Priority Linkset-name -------- -------- ----------------------- 0.0.0/0 7 STP1-STP4 5.5.0/16 3 STP1-STP3 5.5.5/24 3 STP1-STP2 . . 122.5.5 5 STP1-STP2 . . 243.200.1 6 STP1-STP3