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Ethernet Fabric (VDX, CNA)

VDX 6730 - Connecting a VCS Ethernet Fabric to a Fibre Channel Fabric

by brook.reams on ‎08-30-2011 05:50 AM - edited on ‎04-18-2014 09:28 AM by pmadduru (4,004 Views)


Brocade has announced availability of the VDX 6730 Data Center Switch and Brocade Network Operating System (NOS) 2.1.  The VDX 6730 can connect the VDX 6720 and newly announced VDX 6710 switches forming a VCS Ethernet fabric with connectivity to a native Fibre Channel fabric.

The Brocade VDX 6730 supports all the standard features and benefits of VCS fabric technology:

  • Automated Migration of Port Profiles (AMPP)
  • VMware Network Automation
  • Lossless fabric links with DCB
  • Automatic formation of 10 GE ISL links
  • Automatic formation of Brocade ISL Trunks
  • Brocade virtual LAG (vLAG) to other devices (servers, switches, routers) for resiliency and high availability.


The VDX 6730 supports an FCoE Fibre Channel Forwarder (FCF) on 10GE ports and Fibre Channel ports capable of 2/4/8 Gbps link rates.  Inside a VCS Ethernet fabric, FCoE traffic can co-exist on the same ISL or Brocade ISL Trunk as IP traffic.  So, a VCS Ethernet fabric allows FCoE traffic to span multiple VDX switches (called multi-hop FCoE) between the server and the storage array.  Including a VDX 6730 in a VCS fabric provides connectivity to Fibre Channel fabrics and storage.


VDX 6730 Data Center Switches

The VDX 6730 Data Center Switch is available in two models, the 1U 6730-32 and the 2U 6730-76.


9747_VDX 6730-32 Switch.bmp

VDX 6730-32 Switch



9748_VDX 6730-76 Switch.bmp

VDX 6730-76 Switch


Each model has 10GE and 8 Gbps Fibre Channel ports with 24 10GE and eight 8 Gbps FC ports in the 6730-32, and 60 10 GE and 16 8Gbps FC ports in the 6730-76.


When adding the VDX 6730 to a VCS Ethernet Fabric, 10 GE ports in the VDX 6730 are connected to 10 GE ports in other VDX switches in the VCS fabric.  FCoE frames arriving on the 10 GE ports of the VDX 6730 destined for Fibre Channel storage are decapsulated and the Fibre Channel frames switched to the Fibre Channel ports on the VDX 6730 which act as E_Ports.  Similarly, Fibre Channel traffic destined for an FCoE device connected to any VDX switch in the VCS Ethernet fabric arrives on the Fibre Channel E_Port in the VDX 6730, is encapsulated in an FCoE frame and then switched to a 10 GE port for forwarding across the VCS Ethernet fabric.



The Fibre Channel zoning service available in the VCS Ethernet fabric with NOS 2.1 is used to allow devices (host initiator to storage target) to send traffic to each other.  Zoning can be applied to devices in a VCS Ethernet fabric sending FCoE traffic to each other and to FCoE devices in a VCS Ethernet fabric that need to talk to Fibre Channel devices in a separate Fibre Channel fabric.  In the latter case the VCS Ethernet fabric and Fibre channel fabric both connect to a routed SAN backbone fabric using E_Port to EX_Port connections.  LSAN zoning is applied to permit traffic to flow between devices as required.



VDX 6730 Use Cases

There are two important use cases for deploying the VDX 6730, single hop and multi-hop forwarding of FCoE traffic.

FCoE Single Hop Forwarding Use Case

As shown below, a multi-switch VCS Ethernet fabric is being used to transport FCoE storage traffic.


9749_6730 Use Case-Single Hop.bmp

FCoE Single Hop Configuration with VDX 6730 Data Center Switches


VDX 6730 switches are used at the Top-of-Rack (ToR).  FCoE frames are terminated and forwarded as native FC frames from the VDX 6730 to the routed SAN backbone fabric.  Each VDX 6730 consumes a Fibre Channel Domain ID only in the VCS Ethernet fabric since the VCS Ethernet fabric is treated as a separate Fibre Channel fabric as far as FCoE and Fibre Channel switching services are concerned.  Therefore, connecting a VCS Ethernet Fabric with FCoE traffic to an existing native Fibre Channel fabric does not affect the scalability or configuration of that fabric.  Only traffic between devices in the native Fibre Channel and VCS Ethernet fabrics have to be zoned together with LSAN zones.  This approach simplifies management, ensures resiliency and high availability and provides flexibility of storage choices for applications running in servers connected to the VCS Ethernet fabric.


FCoE Multi-hop Forwarding Use Case

As shown below, the VDX 6730 can be used with multi-hop FCoE traffic in a VCS Ethernet fabric.


9794_6730 Use Case-Multihop.bmp

FCoE Multi-hop Configuration with VDX 6730 Data Center Switches


FCoE Traffic is forwarded across multiple VDX switches until it reaches the VDX 6730.  As described before, the FCoE decapsulation/encapsulation and forwarding of native Fibre Channel frames happens in the same way.


Network Isolation Configuration

In the preceding use cases, there is a single VCS Ethernet fabric connected to independent native Fibre Channel fabrics, SAN A and SAN B.  Although the existing Fibre Channel fabrics are isolated, the FCoE traffic in the VCS Ethernet fabric relies on a single network.


For some time, best practice for Fibre Channel SAN design has relied on “air gaps” or isolated SAN fabrics to ensure the highest levels of resiliency and availability.  Unlike TCP/IP traffic, storage traffic expects low latency, lossless delivery with minimal delay when forwarding Fibre Channel frames.  Further, business applications frequently crash should IO to storage be disrupted and in the case of DBMS applications, recovery can take a very long time.  These considerations are not caused by limitations of Fibre Channel but are driven by the SCSI protocol which is the “storage application” using Fibre Channel as its transport.  SCSI was originally designed assuming the connection between the server and the storage was a copper cable.  Replacing the copper cable with a SAN fabric does not replace SCSI expectations for the reliability, resilience, availability and performance of the Fibre Channel fabric.


Below is a configuration that provides physical separation of the storage traffic (FCoE and Fibre Channel) end-to-end.  This configuration follows Fibre Channel fabric best practices.


9751_6730 Use Case-Air Gap.bmp

FCoE Multi-hop Path Isolation Configuration with VDX 6730 Data Center Switches


With the introduction of the VDX 6730 and VDX 6710, VCS technology is better than ever.  A VCS Ethernet fabric provides a scalable way to connect to existing Fibre Channel storage with all the advantages of VCS technology.


This document / wiki was generated from the following discussion: Connecting a VCS Ethernet Fabric to a Fibre Channel Fabric