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| -rw-r--r-- | OsmoBSC/chapters/overview.adoc | 69 | ||||
| -rw-r--r-- | OsmoBTS/chapters/interfaces.adoc | 26 |
2 files changed, 95 insertions, 0 deletions
diff --git a/OsmoBSC/chapters/overview.adoc b/OsmoBSC/chapters/overview.adoc index 580a42e..3bb22cc 100644 --- a/OsmoBSC/chapters/overview.adoc +++ b/OsmoBSC/chapters/overview.adoc @@ -13,6 +13,75 @@ Unlike the highly integrated OmsoNITB, OsmoBSC implements a more classic GSM Base Station Controller with A-bis interface towards BTSs and A interface towards a MSC. +The difference between classic GSM network architecture and +the OsmoNITB based GSM network architecture is illustrated in +<<fig-gsm-classic>> and <<fig-gsm-nitb>>. + +[[fig-gsm-classic]] +.Classic GSM network architecture (simplified) +[graphviz] +---- +digraph G { + rankdir=LR; + MS0 [label="MS"]; + MS1 [label="MS"]; + MS2 [label="MS"]; + MS3 [label="MS"]; + BTS0 [label="BTS"]; + BTS1 [label="BTS"]; + BSC; + MSC [label="MSC/VLR"]; + HLR [label="HLR/AUC"]; + EIR; + SMSC; + MS0->BTS0 [label="Um"]; + MS1->BTS0 [label="Um"]; + MS2->BTS1 [label="Um"]; + MS3->BTS1 [label="Um"]; + BTS0->BSC [label="Abis"]; + BTS1->BSC [label="Abis"]; + BSC->MSC [label="A"]; + MSC->HLR [label="C"]; + MSC->EIR [label="F"]; + MSC->SMSC; +} +---- + +[[fig-gsm-nitb]] +.GSM system architecture using OsmoNITB +[graphviz] +---- +digraph G { + rankdir=LR; + MS0 [label="MS"]; + MS1 [label="MS"]; + MS2 [label="MS"]; + MS3 [label="MS"]; + BTS0 [label="BTS"]; + BTS1 [label="BTS"]; + EXTMNCC [label="Linux Call Router / SoftSwitch / PBX\n(optional)"]; + MS0->BTS0 [label="Um"]; + MS1->BTS0 [label="Um"]; + MS2->BTS1 [label="Um"]; + MS3->BTS1 [label="Um"]; + BTS0->BSC [label="Abis"]; + BTS1->BSC [label="Abis"]; + subgraph cluster_nitb { + label = "OsmoNITB"; + BSC; + MSC [label="MSC/VLR"]; + SMSC; + EIR; + HLR [label="HLR/AUC"]; + BSC->MSC; + MSC->HLR; + MSC->EIR; + MSC->SMSC; + } + MSC -> EXTMNCC [label="external MNCC"]; +} +---- + === Software Components diff --git a/OsmoBTS/chapters/interfaces.adoc b/OsmoBTS/chapters/interfaces.adoc index 242fa23..127d4dc 100644 --- a/OsmoBTS/chapters/interfaces.adoc +++ b/OsmoBTS/chapters/interfaces.adoc @@ -113,6 +113,32 @@ Contrary to that, many classic E1-based implementations of the GSM RAN co-locate the PCU with the BSC. However, the GSM specifications keep the location up to the implementor. +The GPRS network architecture is shown in <<fig-gprs-pcubts>>. + +[[fig-gprs-pcubts]] +.GPRS network architecture +[graphviz] +---- +digraph G { + rankdir=LR; + MS0 [label="MS"]; + MS1 [label="MS"]; + BTS; + BSC; + MSC; + PCU; + SGSN; + GGSN; + MS0->BTS [label="Um"]; + MS1->BTS [label="Um"]; + BTS->BSC [label="Abis"]; + BSC->MSC [label="A"]; + BTS->PCU [label="pcu_sock"]; + PCU->SGSN [label="Gb"]; + SGSN->GGSN [label="GTP"]; +} +---- + The PCU socket interface serves the following purposes: * to pass PCU relevant configuration from BTS to PCU |