[global] title "GPRS PDP Context Activation (L3 only)" [entities] # define the entities in the system (in order) ms "MS" bss "BSS" sgsn "SGSN" dns "DNS" ggsn "GGSN daemon" kernel "GGSN kernel" inet "Internet" [messages] # define the protocol messages in-order ms bss "L1 RACH burst" bss ms "RLC/MAC establishment" ms sgsn "LLC (SM PDP CONTEXT ACT REQ)" sgsn dns "DNS query A record of APN" dns sgsn "DNS response IP address of GGSN" sgsn ggsn "GTP-C (PDP CONTEXT ACT REQ)" ggsn kernel "Create Tunnel" kernel ggsn "Create Tunnel Confirm" ggsn sgsn "GTP-C (PDP CONTEXT ACT ACK)" sgsn ms "LLC (SM PDP CONTEXT ACT ACK)" ms sgsn "LLC (SNDCP (encapsulated IPv4))" sgsn kernel "GTP-U (encapsulated IPv4)" kernel inet "IPv4 packet" inet kernel "IPv4 packet" kernel sgsn "GTP-U (encapsulated IPv4)" sgsn ms "LLC (SNDCP (encapsulated IPv4))"