Figure D.4

@startuml

skinparam monochrome true

skinparam defaultFontName Arial

skinparam classFontSize 10

skinparam sequenceBoxBorderColor #black

participant "**Host A**\nTCP Control Service Gate" as hosta_tcp_ctr 

participant "**Host A**\nAdministration Gate" as hosta_adm

participant "**Host B**\nAdministration Gate" as hostb_adm

participant "**Host B**\nTCP Control Application Gate" as hostb_tcp_ctr 

participant "**Host A**\nTCP Data Service Gate" as hosta_tcp_data 

participant "**Host B**\nTCP Data Application Gate" as hostb_tcp_data 

autonumber

...**Notation:**  Gate Identifier : Pipe Session Open on [P<sub>IN</sub>,P<sub>OUT</sub>]...

hostb_adm->hosta_adm:EVT_ADM_BIND [**TCP_CTR,P<sub>20</sub>**]

hosta_adm->hostb_adm:EVT_ADM_BIND [**TCP_CTR,P<sub>10</sub>**] 

note right : Pipe Session Open  on [P<sub>20</sub>,P<sub>10</sub>]

note left : Pipe Session Open on [P<sub>10</sub>,P<sub>20</sub>]

...

hostb_tcp_ctr->hosta_tcp_ctr: TCP-REQUEST-CONNECTION-Service-Command [Parameters...] on P<sub>10</sub>

activate hosta_tcp_ctr

activate hostb_tcp_ctr

hosta_tcp_ctr-->hostb_tcp_ctr: eTCP-OK [CTX_ID<sub>0001</sub>] on P<sub>20</sub> 

deactivate hostb_tcp_ctr

deactivate hosta_tcp_ctr

...

hostb_tcp_ctr->hosta_tcp_ctr: TCP-GET-STATUS-CONNECTION-Service-Command [CTX_ID<sub>0001</sub>] on P<sub>10</sub>

activate hosta_tcp_ctr

activate hostb_tcp_ctr

hosta_tcp_ctr-->hostb_tcp_ctr: eTCP-OK [CTX_ID<sub>0001</sub>, eLISTEN] on P<sub>20</sub> 

deactivate hostb_tcp_ctr

deactivate hosta_tcp_ctr

...

hostb_tcp_ctr->hosta_tcp_ctr: TCP-CLOSE-CONNECTION-Servcie-Command [CTX_ID<sub>0001</sub>] on P<sub>10</sub>

activate hosta_tcp_ctr

activate hostb_tcp_ctr

hosta_tcp_ctr-->hostb_tcp_ctr: eTCP-OK on P<sub>20</sub> 

deactivate hostb_tcp_ctr

deactivate hosta_tcp_ctr

@enduml