ing units are created in order to spread the signalling load on the signalling units. In the current implementation there can be up to 16 SCTP associations in an association set. IP Signalling Link Sets An IP signalling link contains exactly one association set. An IP signalling link set contains exactly one IP signalling link. IP Signalling Route Set The M3UA is used to transport SS7 signalling traffic over IP interfaces. The MSS allows the use of M3UA with the same signalling user parts as in TDM signalling links. Configuration of these IP signalling links (Figure 4.25) is similar to the configuration of PCM based signalling links. Association 1 IP address =131.228.116.112 Signalling Unit 0 Signalling Link Association set Set 1 Association 2 IP address 131.228.116.122 Signalling Unit 1 Signalling Route Set Signalling Link Set 2 Figure 4.25 Signalling components CS Core Detailed Network Planning Signalling link set SL No. 0 PCM=112 Priority=15 PCM=250 TSL=31 TSL=31 SL No. 1 SPC-1881 PCM=340 Priority=15 SPC=1882 PCM=220 TSL=31 TSL=31 Figure 4.26 Signalling link set Narrowband SS7 Signalling Signalling points are connected to each other by a signalling link. A signalling link can contain a minimum of one signalling channel created in one PCM-TSL (PCM and timeslot). A 2 Mbps PCM link has 32 channels of 64 kbps timeslots. An SS7 signalling link can, however, occupy any one of the timeslots, increasing the bit rate for each link. A signalling link set connects two signalling points in a given signalling network (Figure 4.26). A link set consists of a number of signalling links connecting two signalling points. In SS7 the maximum number of links in a link set is 16. The signalling route is a predetermined path between two signalling points. The signalling link set can be seen as a 'physical' resource, like a pool of channels that can be used, while the route is the logical association between one destination and the link set used to reach it. A signalling route contains one signalling link set. A signalling route set 