Telcordia Notes on the Networks
`Signaling
`
`SR-2275
`Issue 4
`October 2000
`
`Switch
`
`Switch
`
`Switch
`
`A-links
`
`ALC
`
`C-links
`
`ALC
`
`D-links
`
`A1
`
`C-links
`
`A2
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`Switch
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`A-links
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`Network A
`
`Network B
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`Trunks
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`Signaling Links
`
`Figure 6-85. Interconnection of an ALC
`
`6.26.3 CCS Network to Voice Over Packet (VOP) Network Interconnection
`
`A conceptual view of the VOP Network and its interconnection to the Public Switch
`Telephone Network (PSTN) is shown in Figure 6-86. There are various VOP
`network architectures being developed, but one constant in these architectures is
`that signaling interconnection to the PSTN shall be based on the SS7 protocol. The
`architecture discussed in this section is general and is not intended to address all
`specific VOP network implementations.
`
`The VOP architecture can be broken down by the generic Functional Elements
`(FEs) contained with the VOP network. Note that the relevant interfaces to the
`PSTN for these FEs are still under development within the industry. The discussion
`of these FEs does not imply any specific vendor implementation, but is used to
`convey the functional composition of the VOP network and how it may interact with
`the PSTN. The FEs of the VOP as shown in Figure 6-86 are as follows:
`
`(cid:127) Access Gateway
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`(cid:127) Trunk Gateway
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`(cid:127) Signaling Gateway
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`(cid:127) Call Connection Agent
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`(cid:127) Service Agent
`
`(cid:127) Core Network.
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`6–306
`
`AT&T Exhibit 1032
`AT&T v. VoIP, IPR 2017-01384, Page 1
`
`

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`SR-2275
`Issue 4
`October 2000
`
`Telcordia Notes on the Networks
`Signaling
`
`Each of these FEs is discussed in Section 6.26.3.1.
`
`Service
`Agent
`
`Toll-Free, LIDB, etc.
`Databases
`
`Call Connection
`Agent
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`Signaling
`Gateway
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`STP
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`Access
`Gateway
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`Core
`Network
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`SS7 Trunks
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`SS7 Signaling Links
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`Tandem
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`Trunk
`Gateway
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`VOP Network
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`PSTN
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`EO
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`EO
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`EO
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`Figure 6-86. CCS Network to VOP Network Interconnection
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`6.26.3.1
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`Functional Elements of the VOP Network
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`6.26.3.1.1 Access Gateway (AG)
`
`This FE supports the line side interface to the VOP network. Traditional phone lines
`and PBXs currently used for the PSTN can access the VOP network through this FE.
`As such, this FE provides functions such as packetization, echo control, etc. It may
`be associated with a specific Call Connection Agent (CCA) that provides it with the
`necessary call control instructions. On receiving the appropriate commands from
`the CCA, this FE also provides functions such as audible ringing, power ringing,
`miscellaneous tones, etc. It is assumed that the AG has the functionality to set up a
`transport connection through the core network when instructed by the CCA. Thus,
`when a VOP network offers local phone services, it will have this FE. An end-to-end
`call initiated by a VOP local phone customer could originate at this FE and
`terminate at an end office in the CCS/SS7 network.
`
`6.26.3.1.2
`
`Trunk Gateway (TG)
`
`This FE supports a trunk side interface to the PSTN. It terminates circuit-switched
`trunks in the PSTN and virtual circuits in the packet network (core network) and,
`as such, provides functions such as packetization of voice. Even though it
`terminates trunks in the PSTN, it is assumed that this FE does not provide the
`resource management functions for trunks that it terminates. However, it is
`assumed that the TG has the capability to set up and manage transport connections
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`6–307
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`AT&T Exhibit 1032
`AT&T v. VoIP, IPR 2017-01384, Page 2
`
`

`

`Telcordia Notes on the Networks
`Signaling
`
`SR-2275
`Issue 4
`October 2000
`
`through the core network when instructed by the CCA. It may be associated with a
`specific CCA or multiple CCAs which provide it with the necessary call control
`instructions.
`
`6.26.3.1.3 Signaling Gateway (SG)
`
`This FE is used to interconnect the VOP network to the PSTN signaling network. It
`terminates SS7 links from the PSTN CCS/SS7 networks and thus provides, at a
`minimum, MTP Level 1 and 2 functionality. It subsequently communicates with one
`or more CCAs to support the end-to-end signaling for calls and services within the
`PSTN.
`
`6.26.3.1.4 Call Connection Agent (CCA)
`
`This FE provides much of the necessary call processing functionality to support
`voice on the packet network. It processes messages received from various other
`FEs to manage call states. It communicates with other CCAs to set up and manage
`end-to-end calls. CCAs interact with AGs and TGs using call control commands. For
`an end-to-end call between the VOP network and the PSTN, the call processing
`application in the CCA will interact with the PSTN end offices using ISUP that is
`transported through the SG and the PSTN STPs.
`
`6.26.3.1.5 Service Agent (SA)
`
`This FE generates Transaction Capabilities Application Part (TCAP) messages to
`interact with SCPs for vertical services (Intelligent Network services) such as Toll-
`Free and Local Number Portability (LNP). The SA also has the capability to launch
`TCAP queries to SCPs in the traditional PSTN via the SG.
`
`6.26.3.1.6 Core Network
`
`The core network provides transport for the VOP network. The core network could
`utilize various technical alternatives such as ATM, IP over ATM, or even pure IP
`without ATM. The concept behind the signaling and control in the core network is
`that the signaling for the call control is bearer technology independent and that a
`separate bearer signaling (e.g., Private Network Node Interface [PNNI] for
`Asynchronous Transfer Mode [ATM]) is used for establishing a bearer connection
`across the core network.
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`6–308
`
`AT&T Exhibit 1032
`AT&T v. VoIP, IPR 2017-01384, Page 3
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`

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`SR-2275
`Issue 4
`October 2000
`
`Telcordia Notes on the Networks
`Signaling
`
`6.26.3.2
`
`Interconnection of the SG and TG to the PSTN
`
`As stated in Section 6.26.3, Figure 6-86 shows the interconnection of a VOP network
`to the PSTN. Interconnection between the VOP network and the PSTN uses the SG
`and TG of the VOP network and the STP and tandem switch of the PSTN.
`Specifically, the TG in the VOP network has SS7 trunking to the tandem switch of
`the PSTN. The SG has SS7 signaling links to the mated STP pair of the PSTN.
`
`The SS7 signaling links between the SG and mated STP pair may be A-links, D-links,
`or Bridge Links (B-links). The type of link set chosen is influenced by the method
`used to identify the VOP network from the view of the PSTN. For example, if A-links
`are used as the method of interconnection, the entire VOP network including all
`network elements can be viewed as one SEP by the PSTN (i.e., the VOP network is
`identified by one Point Code [PC]). However, if the mated STP pair in the PSTN can
`be interconnected to the VOP network by a pair of SGs, B/D-links may be used. In
`the B/D-link interconnection scenario, the PCs of the SG pair will be different from
`the PC of the TG. This is the same interconnection architecture used when
`interconnecting two mated STP pairs in the PSTN. There are also other
`considerations (e.g., capacity, reliability, SS7 message routing, network
`management) that must be examined when choosing an interconnection
`architecture.
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`6–309
`
`AT&T Exhibit 1032
`AT&T v. VoIP, IPR 2017-01384, Page 4
`
`