Community TDMSS7 Network » History » Version 1
laforge, 01/01/2022 09:09 PM
1 | 1 | laforge | h1. Community TDM/ISDN/SS7 Network |
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3 | This wiki page describes some ideas about creating a community TDM/ISDN/SS7 network, enabling retronetworking enthusiasts around the world to interconnect their TDM equipment, such as PBXs, telephony switches, RAS servers, access multiplers, etc. |
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5 | For classic analog telephones, there is the C*NET (https://www.ckts.info/). This is basically the same idea but for one later generation of technology: Digital TDM/PDH/ISDN/SS7 networks. |
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8 | h2. Underlying Protocol / Hardware |
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10 | The underlying transport protocol is being designed around the wiki page[[e1-t1-adapter:Proposed_efficient_TDMoIP]]. The initial hardware implementation is likely going to be an [[e1-t1-adapter:icE1usb]] attached to some kind of [embedded] Linux sytem like a Raspberry Pi. |
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13 | h2. TDM layer hub / cross-connect |
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15 | The TDM layer would allow to interconnect any E1 line (or even only some timeslots of a line) with any other E1 line. It doesn't interpret the payload but just passes it around. |
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18 | h2. Services |
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20 | h3. Classic SS7 |
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22 | Classic SS7 (MTP2/MTP3 plus TUP/ISUP) would permit to connect STPs and SPCs, such as those of telephony exchanges / switches. |
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24 | A user connecting to the SS7 service would need to be allocated point codes. |
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27 | h3. ISDN PRI |
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29 | ISDN (Q.921/Q.931) would permit to connect equipment like PBXs. The hub offers the NT / central office function, while the client side implements the TE function. |
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31 | A user connecting to the ISDN PRI service would need to be allocated telephone nubmers in the dialling plan. |
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33 | On the hub side, the PRI lines and ISDN service could be terminated in a yate or Freeswitch instance. |
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36 | h3. SCCP/MAP/TCAP |
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38 | SCCP/MAP/TCAP on top of SS7 can be used to provide interworking between private cellular networks. |
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41 | h3. ISDN BRI |
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43 | ISDN BRI service is expected to initially only be obtained indirectly: By connecting a ISDN PRI capable PBX to the hub, and then locally connecting to ISDN BRI ports of the PBX. |
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45 | At a later point, one could consider implementing a ISDN BRI version of the TDMoIP protocol and some software implementation for ISDN BRI cards that support NT mode. |