Source: (Hedgedoc.org)[https://demo.hedgedoc.org/features?both]

Diagrams

UML Sequence Diagrams

You can render sequence diagrams like this:

    sequenceDiagram
        Client-->>DHCPsever: Pxe DHCP request
        DHCPsever-->>Client: DHCP Offer with IP Address
        DHCPsever-->>Client: DHCP Offer with Next Server Info
        DHCPsever-->>Client: DHCP Offer with Boot File name
        Client-->>TFTPserver: Client Contacts the Next server using ip address given by the DHCP
        Client-->>TFTPserver: Client requests the boot file given by the DHCP 
        TFTPserver-->>Client: Provides the Boot File required

More information about sequence diagrams syntax here.