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SEVENSTAX TCP/IP is an internet protocol stack designed specifically for the use in embedded systems. The variant SEVENSTAX TCP/IP-Multidevice provides the possibility to use multiple Layer 2 interfaces in parallel. 

This includes:

  • serial interfaces via Point-to-Point Protocol (PPP) such as Modems (analog/GPRS/UMTS/LTE)
  • Ethernet interfaces
  • WIFI
  • USB via ECM/NCM or RNDIS

For each interface a separate IP configuration is used (IP address, Subnet mask). The operation of the single interfaces is controlled by the internal routing table. Additionally, static routing (IP forwarding) between the interfaces can be installed.

In addtion to the Internet Protocol Version 4 (IPv4) all important protocols are included.

  • Internet Protocol Version 4 (IPv4) based on RFC 791 
    • Subnet mask with CIDR blocks (Classless Inter-Domain Routing, RFC 1518 and RFC 1519)
    • IP-fragmentatoin and reassembly according to RFC 791, RFC 815
    • Validity testing of IP adress/subnet  (RFC 3330)
  • Transmission Control Protocol (TCP) based on RFC 675, RFC793, RFC 1323
    • Checksum according to RFC 1071
    • TCP extensions according to RFC 1323
    • Error correction algorithms  (RFC1122)
    • Simultaneous operation of TCP server and client mode
    • No limitation of simultaneous connections
    • Full frame size control (TCP segmentation according to RFC 879) 
    • Sliding window technique  (RFC 793)
    • Keep-alive packets  (RFC 1122)
    • Protection against „Sequence Number Attacks“  (RFC 1948)
    • Fast retransmission algorithm
  • User Datagram Protocol (UDP) based on RFC 768

  • Domain-Name-System (DNS) Client basierend auf RFC 1034, RFC 1035
  • Internet Control Message Protocol (ICMP) based on RFC 792
    • Sending of ICMP host messages
    • Receiving of ICMP host and router messages
  • Internet Group Management Protocol (IGMP)
    • Version 1 (RFC 1112)
    • Version 2 (RFC 2236)
  • (Simple) Network Time Protocol (NTP/SNTP) based on RFC 958, 4330

Layer 2 protocols

SEVENSTAX TCP/IP-Multidevice provides the possibility to use multiple Layer 2 interfaces in parallel.

The following L2 protocols/services are available:


The follwoing subprotocols and services are available separately: