The minimum packet size in Ethernet is 64 bytes. Even though Ethernet packets support a much larger payload compared to RapidIO, their maximum protocol efficiency is only slightly more than 97 percent due to the large headers required for the software-based reliable delivery protocols.
Ethernet is currently working to specify 40 Gbps and Gbps links. This work builds on the existing 10 Gbps, single-lane Ethernet standards. Lossless Ethernet reduces packet loss due to congestion in the Ethernet network by establishing link-level flow control. This drastically increases the efficiency of the overall network since the amount of packet discarding is greatly diminished.
Lossless Ethernet under congestion can perform in a manner similar to RapidIO. Although the Ethernet ecosystem is much larger than that of RapidIO, Ethernet still has just three suppliers of switch devices — Marvell, Fulcrum, and Broadcom. These manufacturers have a wide range of products for the Internet.
In support of the Lossless Ethernet initiative, these vendors have announced switches with sub-microsecond latency. System designers who find the capabilities of DCE attractive can also consider the established RapidIO ecosystem as a source of components. Similarly, the new capabilities of DCE have allowed system designers to consider it as an alternative to RapidIO in some applications.
Although it is obvious that the DCE header is much larger than a RapidIO header, what may not be apparent is the growing number of similarities between the two packet formats. Table indexing is the only mechanism a RapidIO switch needs for operating a routing table. Many switches in the RapidIO ecosystem have one routing table per port. The largest difference between the packet formats is their maximum size. Common Internet Ethernet packets are about bytes in size.
Jumbo packets can be more than bytes. The largest RapidIO packet, however, is only bytes. Despite the differences in packet size, overall protocol efficiency is approximately the same: Internet Ethernet is around 97 percent while RapidIO is approximately 95 percent. Messaging capabilities enable both technologies to support encapsulation of other protocols.
RapidIO guarantees packet delivery on each link. In the case of a m 10 Gbps fiber connection, recovery can be accomplished with the exchange of three control symbols, which can occur in approximately 2.
For a chip-to-chip link, the exchange can be completed in less than nsec. Lossless Ethernet is a partial misnomer, because packets can still be lost due to transmission error. Error recovery, therefore, has much higher latency than RapidIO. This high latency has significant impact for system resource usage and performance. Making a large change in direction, the Ethernet community effectively split the Ethernet market into Internet and Data Center halves.
In the context of the planet-spanning network called the Internet, network-layer flow control, rather than link-level flow control, achieves higher throughput. Latencies in the planet-spanning Internet Ethernet half, and the complexity and unpredictability of the network topology, make network-level flow control the most effective type of flow control mechanism.
The vast majority of Ethernet technology is Internet Ethernet. Internet Ethernet technology depends on significant processing power in the form of switch and router platforms. Figure 2 shows a typical Internet Ethernet switch box, which can also be a router. Figure 2: Internet Router Block Diagram. The Internet router consists of a number of line cards, each connected to a redundant switch fabric.
Local control plane processors are in charge of line card behavior, with each local processor connected to the master control plane processor. Each line card contains an NPU, which is responsible for classifying and scheduling Ethernet packets as they are received to enforce security, meter traffic for service-level agreements, and shape traffic to optimize Internet bandwidth.
If a packet grows too large because of these header modifications, the packet may be split into multiple packets. RapidIO Fabrics provide low latency sensor streaming along with high availability features that address the functional safety requirements of next generation autonomous systems.
RapidIO Fabrics deliver high reliability, fault tolerance and seamless sensor streaming support to any application where failure is not an option. RapidIO Fabrics provide deterministic and guaranteed data delivery services plus a flexible system topology for tightly controlled Industrial Automation applications.
RapidIO provides chip-to-chip, board-to-board and shelf to shelf peer to peer connectivity at performance levels scaling to s of Gigabits per second and beyond. Members of RapidIO. Learn more about RapidIO. RapidIO Fabrics were originally designed to support connecting different types of processors from different manufacturers together in a single system. This flexibility has driven the widespread use of RapidIO Fabrics in wireless infrastructure equipment where there is a need to combine general purpose, digital signal, FPGA and communication processors together in a tightly coupled system with low latency and high reliability.
The key requirement for evolving the PCIe architecture is to continue to provide performance scaling consistent with bandwidth demand from a variety of applications with low cost, low power, and minimal perturbations at the platform level. The final PCIe 4. The RapidIO standard is finely tuned for embedded applications. Defense and aerospace customers continue to rely on RapidIO for mission-critical systems and increased automation of unmanned vehicles. The latest enhancements to the RapidIO road map were announced last summer when the RTA announced a technology road map of enhancements with the Serial RapidIO 10xN set of specifications that moves the protocol to serial lane speed of 10 Gbps and higher supporting individual port speeds that scale beyond Gbps Figure 2.
The new technology road map scales the needs of RapidIO customers in the wireless, defense, aero-space, imaging, video, and server markets beyond what can be implemented in other interconnect protocols and sets the stage for OEMs to develop systems with scalable backplanes. Figure 2: RapidIO technology and applications road map Click graphic to zoom by 1.
Initially, the RapidIO 10xN specification will support greater than 10 Gbaud per serial lane with lane widths up to x16, resulting in data rates up to Gbps per port. The RapidIO 10xN set of specifications will also scale to serial lane speeds of 25 Gbps and beyond as there are no limitations in the logical and transport layer, thus allowing for the standard to keep in lockstep with main stream PHY technology.
As key to supporting applications, there is a short-reach specification for local interconnect up to 20 cm over one connector on FR4 and a long-reach specification that will support up to 1 m over one connector on FR4. This rugged 6U VPX board, available in both air-cooled and conduction-cooled versions, combines Ethernet and SRIO switching in a single slot for management, control and data plane switching in high performance embedded military systems. This website uses cookies so that we can provide you with the best user experience possible.
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