How to Transition from Legacy Redundant Terminal Bus Packages to Modern PRP and Teaming Architectures in PCS 7

In SIMATIC PCS 7 V8.1 and V8.2, the legacy Redundant Terminal Bus Adapter Package (MLFB: 6ES7652-0XX01-1XF1, which bundled two Intel PCI-Express network cards) is obsolete and discontinued. Modern PCS 7 releases achieve terminal bus high availability using two standardized methods: Parallel Redundancy Protocol (PRP) according to IEC 62439-3 or Intel Advanced Network Services (ANS) / Windows Server network adapter teaming. For greenfield systems, PRP deployed via SCALANCE X-204RNA hardware redundancy boxes or SOFTNET-IE RNA software is the officially recommended standard, providing bumpless, zero-millisecond failover across dual independent LAN networks.

Legacy Terminal Bus Adapter Bundles vs Modern Standards

In early PCS 7 versions (PCS 7 V6.x and V7.0), industrial computers lacked native dual-port server network adapters:
* The Legacy Bundle (6ES7652-0XX01-1XF1): Siemens offered a dedicated hardware adapter package containing two Intel Gigabit PCI-Express cards pre-tested for Adapter Fault Tolerance (AFT).
* The Modern IPC Reality:
* Modern SIMATIC Industrial PCs (such as IPC547E, IPC647D, IPC847D) incorporate dual onboard Gigabit Ethernet interfaces as standard hardware.
* Operating systems evolved to support standardized network redundancy protocols.
* Consequently, the dedicated 6ES7652-0XX01-1XF1 bundle was declared obsolete and is no longer orderable for PCS 7 V8.1 or V8.2.

Parallel Redundancy Protocol (PRP): Hardware vs Software Mode

Parallel Redundancy Protocol (PRP) is the premier international standard (IEC 62439-3) for mission-critical industrial Ethernet:

Bumpless Redundancy Principle:
A sending node transmits duplicate frames over two completely segregated networks: LAN A and LAN B.
The receiving node accepts whichever frame arrives first and discards the duplicate.
If a switch, cable, or transceiver fails, zero packets are lost (0 ms failover time).
Hardware-Based PRP (RedBox):
Deploy SCALANCE X-204RNA redundancy boxes (6GK5204-0BA00-2KB2).
Connects standard single-port PCs to both LAN A and LAN B without requiring specialized network drivers on the PC.
Software-Based PRP (SOFTNET-IE RNA):
Install SIMATIC NET SOFTNET-IE RNA software on the IPC.
Binds two physical onboard NICs into a single virtual PRP network adapter in Windows.

Network Adapter Teaming (Intel ANS) on Modern Industrial PCs

For facilities not implementing dual-ring PRP architectures, network adapter teaming remains an approved alternative:

Adapter Fault Tolerance (AFT):
Uses the two integrated Intel Ethernet adapters on the SIMATIC IPC.
Configured via Intel PROSet / Intel ANS in Windows Device Manager.
One adapter operates as Primary; the second adapter remains in hot standby.
Failover occurs within 200 to 500 ms upon cable disconnection.
Switch Fault Tolerance (SFT):
Primary and secondary adapters connect to two separate SCALANCE switches, protecting against physical switch failure.

Migration and Procurement Strategy for PCS 7 V8.1/V8.2

When specifying terminal bus hardware for PCS 7 V8.1 projects:

Do Not Procure 6ES7652-0XX01-1XF1: Remove this obsolete MLFB from equipment schedules.
Procure Standard IPC Hardware:
SIMATIC IPCs ordered with dual Gigabit Ethernet ports (2x Gbit Ethernet (IE/PN)).
Procure PRP Software / Hardware:
For software PRP: SIMATIC NET SOFTNET-IE RNA runtime license per station.
For hardware PRP: SCALANCE X-204RNA EEC managed redundancy switches.
Always validate final license packages and network hardware against the applicable Siemens catalog and authorized distributor quotation.

Comparison of Terminal Bus Redundancy Technologies

The table below compares terminal bus high-availability solutions in SIMATIC PCS 7.

Solution FeatureLegacy Adapter Package (6ES7652-0XX01-1XF1)Modern Intel ANS TeamingParallel Redundancy Protocol (PRP)Failover Latency200 to 500 ms200 to 500 ms0 ms (Bumpless)Network InfrastructureSingle physical LAN (Dual switches)Single physical LAN (Dual switches)Two completely segregated LANsHardware RequiredLegacy PCI-E cardsIntegrated IPC Intel NICsDual NICs + SCALANCE X-204RNA / RNA SoftWindows OS SupportWindows XP / Server 2003Windows 7 / Server 2008 R2 / 2012 R2Windows 7 / 10 / Server 2012 R2 / 2016Product LifecycleDiscontinued / ObsoleteLegacy / Maintenance modeActive Global Standard (IEC 62439-3)

Verification

To confirm that terminal bus redundancy is operational:
1. In Windows Device Manager, verify that either the Intel Teamed Adapter or the SIMATIC NET RNA virtual adapter reports status Healthy.
2. Launch WinCC Runtime on an OS Client connected across the terminal bus to redundant OS Servers.
3. Open a continuous ping from the client to the server: ping -t <Server_IP>.
4. Physically disconnect the primary terminal bus network cable from the client or server:
* If using PRP: Confirm zero dropped ping packets (0 ms recovery).
* If using Teaming: Confirm a maximum of 1 dropped packet before connection resumes.
5. In WinCC, verify that operator screens, alarms, and trends remain completely uninterrupted.

Limitations and Operational Precautions

In PRP networks, never bridge LAN A and LAN B together; bridging creates a network loop that floods both subnets.
Intel ANS network teaming is deprecated in Windows 10; use native Windows teaming or PRP when modernizing client operating systems.
Do not mix 100 Mbps and 1000 Mbps adapters within the same teaming group.
Always validate final network switches, communication adapters, and software licensing against the applicable Siemens catalog and authorized distributor quotation.

Engineer FAQ

Can I order part 6ES7652-0XX01-1XF1 for a new PCS 7 V8.1 system?

No. That part number is discontinued and obsolete. Modern SIMATIC IPCs include integrated dual network cards that support PRP or teaming out of the box.

What is the primary advantage of PRP over network teaming?

PRP transmits duplicate frames simultaneously over two separate networks, providing bumpless failover with zero dropped packets and zero failover latency.

Does PRP require specialized network switches?

The two intermediate network rings (LAN A and LAN B) can use standard SCALANCE X managed switches. Only the boundary nodes require PRP-aware interfaces (SCALANCE X-204RNA or SOFTNET-IE RNA).