Skip to main content

G8032 V2 ETHERNET RAIL PROTECTION SWITCH

ERPS (Ethernet Ring Protection Switching) is an “ethernet traffic” recommendation published by ITU-T under G.8032 that can compensate for line breaks in less than 50 ms, operates in a ring topology and prevents the formation of a loop at the ethernet level. G.8032v1 describes a single ring topology, while G.8032v2 supports multiple ring or ladder topology.

ERPS defines the protected switching mechanism and Ethernet level network rings. Ethernet Ring is a topology that enables wide area multihoming. The mechanism defined by this recommendation provides very high availability and never allows a loop to occur. Any loop will render the system completely inoperable.

Each Ethernet ring node is connected by two independent links to neighboring nodes in the same ring. A ring link is formed by two neighboring Ethernet ring nodes. A port in a ring connection is called a ring port. An ethernet ring must have at least two ethernet ring nodes.

THE BASICS OF RAIL PROTECTED SWITCHING ARCHITECTURE ARE AS FOLLOWS:

  • Never loop creation.
  • Use of learning, forwarding and filtering database mechanisms defined by the “Ethernet flow forwarding function (ETH_FF)”.

Prevention of looping is achieved by ensuring that traffic is guaranteed to flow on all links except one. This link on which traffic flow is blocked is called a Ring Protection Link (RPL). Under normal conditions, the RPL remains blocked. One of the nodes connected to the RPL is responsible for blocking. If a fault occurs in the Ethernet ring, the node blocking the RPL unblocks it (unless the fault is in the RPL) and allows the RPL to be used for traffic transmission. The other neighboring node may also take part in blocking and releasing the RPL.

G.8032V2:

G.8032 version 2 defines several features that have been added to the single ring. These are:

  • Multiple ring/ladder network support
  • Returning/not returning to the initial state after troubleshooting
  • Administrative commands: Forced Switch (FS), Manual Switch (MS) to block a specific ring port
  • Flush FDB (Filtering database) Logic significantly reduces flush FDB operations in the system.
  • Multiple ERP support in a single ring