EPDG implementation plan » History » Version 2
laforge, 11/15/2021 07:37 PM
1 | 2 | laforge | {{>toc}} |
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3 | 1 | laforge | h1. EPDG implementation plan |
4 | 2 | laforge | |
5 | h2. The big picture |
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6 | |||
7 | Ideally, we want to reuse existing code whenever possible, rather than reinvent the wheel. Time will tell, if this works out or if we have to rewrite more of it. |
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8 | * StrongSwan charon for handling IKEv2 and managing the IPsec SAs in the kernel IPsec |
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9 | * Erlang DIAMETER application for all the related interfaces |
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10 | * Erlang gtplib for S2b |
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11 | |||
12 | This means we will have two major "applications" running: |
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13 | * charon |
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14 | * ePDG (likely in Erlang) |
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15 | |||
16 | Between those two we will need some kind of non-standard, custom interface. For now I've called it "CEAI" for (Charon External AKA Interface) |
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17 | |||
18 | h2. Control Plane |
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19 | |||
20 | * *red* color indicates elements / interfaces to be implemented. |
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21 | |||
22 | {{graphviz_link() |
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23 | digraph G { |
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24 | rankdir=LR; |
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25 | subgraph cluster_swan { |
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26 | label = "StrongSWAN domain"; |
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27 | charon; |
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28 | } |
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29 | subgraph cluster_erlang { |
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30 | label = "Erlang domain"; |
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31 | ePDG [color=red]; |
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32 | AAA [label="3GPP AAA Server", color=red]; |
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33 | } |
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34 | HSS; |
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35 | PGW; |
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36 | PCRF |
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37 | UE; |
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38 | |||
39 | charon -> ePDG [label="CEAI", color=red]; |
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40 | |||
41 | UE -> charon [label="IKEv2"]; |
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42 | ePDG -> AAA [label="SWm (DIAMETER)", color=red]; |
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43 | AAA -> HSS [label="SWx (DIAMETER)", color=red]; |
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44 | AAA -> PGW [label="S6b (DIAMETER)", color=red]; |
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45 | |||
46 | ePDG -> PGW [label="S2b (GTPv2C)", color=red]; |
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47 | ePDG -> PCRF [label="Gxb", color=red, style=dashed]; |
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48 | PGW -> PCRF [label="Gx (DIAMETER)"]; |
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49 | } |
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50 | }} |
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51 | |||
52 | |||
53 | h2. User Plane |
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54 | |||
55 | * *red* color indicates elements / interfaces to be implemented. |
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56 | * *blue* color indicates control-plane elements controlling the user plane |
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57 | |||
58 | {{graphviz_link() |
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59 | digraph G { |
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60 | rankdir=LR; |
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61 | |||
62 | subgraph cluster_swan { |
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63 | label = "StrongSWAN domain"; |
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64 | { rank=same; |
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65 | ipsec [label="Linux kernel\nIPsec"]; |
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66 | charon [color=blue]; |
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67 | } |
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68 | charon -> ipsec [label="netlink", color=blue]; |
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69 | } |
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70 | subgraph cluster_erlang { |
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71 | label = "Erlang domain"; |
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72 | { rank=same |
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73 | gtp [label="Linux kernel\nGTP"]; |
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74 | ePDG [color="blue"]; |
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75 | } |
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76 | ePDG -> gtp [label="netlink", color=blue]; |
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77 | } |
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78 | PGW; |
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79 | UE; |
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80 | |||
81 | UE -> ipsec [label="ESP/UDP"]; |
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82 | ipsec->gtp [label="kernel IP stack"]; |
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83 | gtp -> PGW [label="S2b (GTPv1U)", color=red]; |
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84 | } |
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85 | }} |
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86 | |||
87 | h2. Interfaces and Procedures |
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88 | |||
89 | h3. ePDG |
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90 | |||
91 | |||
92 | h4. S2b to PGW (GTPv2C) |
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93 | |||
94 | h5. Create Session Request / Response |
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95 | |||
96 | h5. Delete Session Request / Response |
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97 | |||
98 | h5. Modify Bearer Request / Respone (not needed?) |
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99 | |||
100 | h5. Modify Bearere Command (not needed?) |
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101 | |||
102 | h5. Bearer Resource Command (not needed?) |
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103 | |||
104 | h5. Create Bearer Request / Response |
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105 | |||
106 | h5. Update Bearer Request / Response (not needed?) |
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107 | |||
108 | |||
109 | h4. SWm to AAA (DIAMETER) |
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110 | |||
111 | h5. Diameter-EAP-Request (DER) / Diameter-EAP-Response (DEA) |
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112 | |||
113 | h5. Diameter-AA-Request (AAR) / Diameter-AA-Response (AAA) |
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114 | |||
115 | h5. Session-Termination-Request (STR) / Session-Termination-Answer (STA) |
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116 | |||
117 | h5. Re-Auth-Requst (RAR) / Re-Auth-Answer (RAA) |
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118 | |||
119 | h5. Abort-Session-Request (ASR) / Abort-Session-Answer (ASA) |
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120 | |||
121 | |||
122 | h4. SWu to UE (IKEv2, ESP) |
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123 | |||
124 | |||
125 | h4. Gxb to PCRF (not needed?) |
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126 | |||
127 | |||
128 | h3. 3GPP AAA Server |
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129 | |||
130 | h4. SWx to HSS (DIAMETER) |
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131 | |||
132 | h5. Push-Profile-Request (PPR) / Push-Profile-Answer (PPA) |
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133 | |||
134 | h5. Registration-Termination-Request (RTR) / Registration-Termination-Answer (RTA) |
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135 | |||
136 | h5. Multimedia-Auth-Request (MAR) / Multimedia-Auth-Answer (MAA) |
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137 | |||
138 | h5. Server-Assignment-Request (SAR) / Server-Assignment-Answer (SAA) |
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139 | |||
140 | |||
141 | h4. S6b to PGW (DIAMETER) |
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142 | |||
143 | FIXME |
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144 | |||
145 | h4. SWm to ePDG (DIAMETER) |
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146 | |||
147 | see above. |