RoCE Topology

RoCE leverages the functions of RDMA to expedite and accelerate communications between applications hosted and running on clusters of servers and storage arrays. RDMA was first used with InfiniBand (IB) fabrics. RoCE is primarily established by replacing the IB link layer with an Ethernet Ethernet is a network protocol for data transmission over LAN. link layer to transfer data. Data centers can benefit from RDMA using a converged, high performance infrastructure that supports TCP/IP Transmission Control Protocol/ Internet Protocol. TCP/IP is the basic communication language or protocol of the Internet..

The following figures illustrates the structure of RoCE:

Figure 1   RoCE Topology

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The following are the two versions of RoCE:

RoCE v1

The RoCE v1 protocol is an Ethernet link layer protocol allowing two hosts in the same Ethernet broadcast domain to communicate.

RoCE v2

The RoCE v2 protocol replaced the IB network layer with a standard IP and UDP User Datagram Protocol. UDP is a part of the TCP/IP family of protocols used for data transfer. UDP is typically used for streaming media. UDP is a stateless protocol, which means it does not acknowledge that the packets being sent have been received. header enabling the traffic to be routed. RoCE v2 is used on both layer-2 and layer-3 networks as packet encapsulation includes IP and UDP headers. Layer-3 routing is made possible by this, bringing RDMA to networks with multiple subnets Subnet is the logical division of an IP network. for increased scalability.

To deploy RoCE v2, see Deploying RoCE v2 on Aruba CX Switches.

The following figure differentiates the structures of RoCE v1 and RoCE v2:

Figure 2   RoCE v1 and RoCE v2