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This chapter presents various issues—dial plan, billing/settlement, and security—as they relate to feature enhancements to Services A and B. The following service options are discussed:
The DGK can make limited egress CSR decisions by using the sequential LRQ feature, which is available to the applications using DGK routing. Generally speaking, this means any TDM partners and DGK peering partners, but also includes any OSP partners where an OSP interconnection zone is used (as opposed to a direct implementation on the wholesaler's GWs).
In this CSR application, the sequential LRQ feature is used to route a call to different carriers, each of whom supports a different destination. For example, the wholesaler may provision its GKs to route certain destination patterns to carrier A first. If carrier A (an Internet telephony service provider, or ITSP) is unavailable, as a result of, say, a location request reject (LRJ) or LRQ timeout, the wholesaler may decide to route the call to carrier B (an interexchange carrier, or IXC), then to carrier C, and so on. Figure 7-1 illustrates this application.
Note the following restrictions on egress CSR:
The GK routes calls on the basis of DNIS. The wholesaler statically configures a list of possible egress carriers, and these are tried in order. Routing decisions are not based on which carrier sourced the call. For example, the fact that carrier A sourced the call does not determine that carrier A will be selected for the termination.
For ITSP carriers, this is fairly simple. Interconnecting ITSPs are seen as single remote zones to which the wholesaler DGK sends LRQ messages. For interconnecting TDM carriers, this implies the following:
The order of sequential LRQs is configured statically. Consequently, there is no provision for percentage-based routing, maximum minute cutoffs, and the like. Egress carriers are always chosen from a statically configured list of routes. If the DGK determines that an OSP interconnection zone handles a route, it is possible that the OSP server returns a terminating GW on the basis of advanced routing logic (if so provisioned). For example, the OSP server may dynamically select a least-cost, terminating carrier on the basis of time of day or best voice quality.
The following applies to Templates A1 and B1.
In addition to the basic large-scale H.323 dial plan concept as discussed in Basic Dial Plan, additional LRQ entries may be inserted into the DGK. to try different TDM interconnect zones sequentially in a limited egress CSR application.
Billing and settlement are done as in the simple carrier interconnect application discussed in Billing/Settlement.
Security options are the same as for the simple carrier interconnect application discussed in Security.
The following applies to Templates A2 and B2.
This is the same as discussed in the TDM-to-TDM call topology (see Template A1: TDM-to-TDM Call Topology), except that sequential LRQ entries into the DGK may include IP-based carriers with which a DGK peering relationship is made.
Billing and settlement are done as in the simple carrier interconnect application discussed in Billing/Settlement.
Security options are the same as for the simple carrier interconnect application discussed in Security.
The following applies to Templates A3 and B3.
The dial plan is administered in much the same way as described in the simple interconnect application (see Dial Plan). However, in this case the wholesaler may attempt different terminating carriers for a call. Actual methods depend on whether OSP is implemented directly on the GW or through an OSP interconnection zone.
For OSP implementations directly on the POP GWs, the OSP server may be provisioned to return the best egress carrier to the originating GW. However, the Cisco Wholesale Voice Solution does not address any specific intelligent provisioning on the OSP server.
If OSP is done by means of a back-to-back GW zone, then the LRQ method discussed in Applicability: Templates A2 and B2, may be used on the DGK to select a terminating carrier sequentially. These terminating carriers may include multiple OSP interconnect zones. If the selected terminating carrier is an OSP back-to-back zone, then the OSP GW can additionally receive a preferred terminating GW from the OSP server on the basis of OSP server provisioning. Again, the Cisco Wholesale Voice Solution does not address any specific, intelligent provisioning on the OSP server.
Basic AAA-based billing is done from the back-to-back GWs as discussed in Billing/Settlement. The AAA record collected from the ingress GW contains information about the originating IP carrier, whereas the AAA record collected from the egress GW contains information about the terminating carrier. The billing application can then generate a CDR for the call and the wholesaler may settle between carriers as usual.
Security options are the same as for the simple carrier interconnect application discussed in Security.
The following applies to Templates A4 and B4.
Additional sequential LRQ entries are inserted into the DGK to point to various other IP interconnection partners. These IP interconnect partners may be other DGK-based interconnection partners through a back-to-back GW zone, or an OSP-based interconnect partner through a back-to-back OSP interconnection zone.
Basic AAA-based billing is done from the back-to-back GWs as discussed in Billing/Settlement. The AAA record collected from the ingress GW contains information about the originating IP carrier, whereas the AAA record collected from the egress GW contains information about the terminating carrier. The billing application can then generate a CDR for the call and the wholesaler may settle between carriers as usual.
Security options are the same as for the simple carrier interconnect application discussed in Security.
The following applies to Templates A5 and B5.
This extends the method described in Template A3: TDM-to-IP-Based Interconnect with OSP, to include sending calls to another OSP provider through another back-to-back GW zone or another DGK-based service provider, depending on LRQ routing entries in the DGK.
Billing is between OSP providers and is done as in Template A3: TDM-to-IP-Based Interconnect with OSP, but for two OSP back-to-back GW zones. The originating zone provides settlement CDRs for the originating carrier and the terminating zone provides settlement CDRs for the terminating carrier. If the call is instead sent to a DGK interconnect, then AAA RADIUS records are used on that side. A mediation application may be used to reconcile the AAA with the OSP usage records.
Security options are the same as for the simple carrier interconnect application discussed in Security.
In this application a back-to-back GW must be used, because Clarent does not support either DGK LRQ messaging or OSP. This architecture is very similar to that of using back-to-back GWs to interconnect OSP partners, except that here the relationship is an H.323 GW to a GK, instead of to OSP.
One of the back-to-back GWs registers to a Clarent GK in the Clarent-based service provider's network, and the other registers to a Cisco GK in the wholesaler's network.
Note the following limitations where Clarent-based interconnect is used.
The use of back-to-back GWs enables Clarent-based interconnect partners to exchange traffic not only with wholesaler TDM-based interconnects, but also with other IP-based interconnect partners. Those partners may be either DGK- or OSP-based. It may be necessary to modify the dial plan architecture to support DGK-based IP carrier interconnects.
To interconnect with Clarent-based networks, H.323 interoperability must be supported between Cisco GWs and Clarent GKs. Currently, only voice-bearer interoperability is supported for G.711, G.723.1, and G.729 codec types.
Because of tandem compression, back-to-back GWs impair voice quality.
The following applies to Templates A2 and B2.
The impact of this application on the dial plan closely models that of the simple carrier interconnect application discussed for Template A2: TDM-to-IP Call Topologies Using DGK-Based IP Interconnect. The basic large-scale H.323 dial plan concept as discussed in Basic Dial Plan, is still used. However, a back-to-back GW zone is added to interconnect with the Clarent-based clearinghouse. The back-to-back GW is provisioned so that one GW registers to the Clarent GK; the other GW registers to the local GK, which manages the Clarent interconnect zone within the wholesaler network.
The DGK simply requires additional LRQ route statements to direct certain destination patterns to the Clarent-based clearinghouse through a zone consisting of back-to-back GWs. To the local GK that manages the Clarent interconnect zone, this looks just like a normal TDM POP and has all the characteristics of the simple interconnect application discussed in Template A1: TDM-to-TDM Call Topology.
The wholesaler may collect AAA RADIUS records from one of the back-to-back GWs in the same manner as described in the simple carrier interconnect above. These may be used to generate a periodic bill to the Clarent-based interconnect partner. Bills received from the Clarent-based interconnect partner may be verified by comparing these CDRs against those generated by Clarent Command Center before settling the bill.
Security options are the same as for the simple carrier interconnect application discussed in Security.
The following applies to Templates A4 and B4.
The dial-plan is similar to that discussed for Template A2: TDM-to-IP Call Topologies Using DGK-Based IP Interconnect. However, the Clarent-based clearinghouse interconnect zone may reach other IP-based networks through the DGK. These interconnecting IP-based networks may be direct DGK peering partners or OSP-based interconnects through an OSP interconnection zone.
Billing is done as in Template A2: TDM-to-IP Call Topologies Using DGK-Based IP Interconnect.
Security options are the same as for the simple carrier interconnect application discussed in Security.
Posted: Wed Jan 22 15:19:45 PST 2003
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