Sgsnemu » History » Version 3
laforge, 09/06/2017 11:26 AM
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3 | 3 | laforge | @sgsnemu@ is part of the [[OsmoGGSN]] project and implements a Serving GPRS Support Node (SGSN) emulator. It can be used for testing Gateway GPRS Support Nodes (GGSNs), GPRS core networks as well as GPRS roaming connections. |
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5 | For more information abou the role of SGSNs and GGSNs, see https://en.wikipedia.org/wiki/GPRS_core_network |
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7 | The GPRS functionality and protocols has been standardized by the Third Generation Partnership Project (3GPP). According to the 3GPP specificaitons, an SGSN has several interfaces. @sgsnemu@ emulates the GN/Gp interface which is used towards GGSNs. |
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9 | The Gn/Gp inteface can be seen as the uplink interface of the SGSN. It is used for communicating with a GGSN which is typically connceted to the Internet (or any other private IP network). The Gn/Gp interface uses the GPRS tunneling protocol (GTP). User data packets (typically IP packets) are tunneled over GTP, which again uses UDP over IP as underlaying transport. |
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11 | @sgsnemu@ will establish a number of tunnels (aka _PDP Contexts_) to the GGSN. An internal ping facility will transmit ping requests through the established tunnels. Alternatively, a local network interface can be created. In this case, @sgsnemu@ will forward packets between the local network interface and the established tunnels on the Gn/Gp interface. |
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13 | @sgsnemu@ uses the TUN/TAP driver for the local interface. A tun network interface is established for each tunnel established to the GGSN. |
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15 | @sgsnemu@ errors are reported using the Osmocom logging framework. |
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17 | 3 | laforge | For detailed syntax, please see the sgsnemu man page included in the [[OsmoGGSN]] distribution. You can also access the man page at http://git.osmocom.org/openggsn/plain/doc/sgsnemu.8 |