I/O, I/O, It's Off to Virtual Work We Go - Page 2

Data Center Ethernet and FCoE

Data center Ethernet (DCE) is a new evolution and extension of existing Ethernet to address higher performance as well as lower latency I/O demands for data centers as a unified interconnect for both network and storage traffic. An example of DCE implementation is Fibre Channel over Ethernet (FCoE), which leverages lower latency, quality of service (QoS), priority groups and other enhancements over traditional Ethernet to be used as a robust storage interconnect.

Figure 4 shows how traditionally separate fiber optic cables are dedicated (in the absence of wave division multiplexing, or WDM) to Fibre Channel SAN and Ethernet or IP-based networks. With FCoE (Figure 5), Fibre Channel absent of the lowest physical layers is mapped onto Ethernet to co-exist with other traffic and protocols, including TCP/IP. Note that FCoE is targeted for the data center as opposed to long distance, which would continue to rely on FCIP (Fibre Channel mapped to IP) or WDM-based MAN for shorter distances.

Figure 4: Separate physical data center I/O networks (interfaces and protocols) today

(Click for larger image)

Figure 5: Ethernet-based unified, converged data center fabric or I/O network

(Click for larger image)

Another component in the taxonomy of server, storage and networking I/O virtualization is the virtual patch panel that masks the complexity of adds, drop, move and changes associated with traditional physical patch panels. For example, a new company leveraging a large installed base and taking mature technology into the future is OptiPath, originally launched as Intellipath. For large and dynamic environments with complex cabling requirements and the need to secure physical access to cabling interconnects, virtual patch panels are a great complement to IOV switching and virtual adapter technologies.

Post a comment
Email Article
Print Article
Share Articles
- Digg
- DZone
- Reddit
- Slashdot
- StumbleUpon
- del.icio.us
- Facebook
- FriendFeed
- Furl

DCE versus IB: And The Winner is?

I do not see InfiniBand disappearing anytime soon, but all of the technology features and capabilities of IB will be at a disadvantage moving forward, given the mass market economies of scale for Ethernet, even with a higher-priced version of Ethernet. For those looking to deploy a unified or converged fabric today, InfiniBand-based solutions are an option, with the ability to bridge to existing Ethernet LANs or WANs along with Fibre Channel-based SANs. Rest assured, for those deploying InfiniBand-based unified, converged or data center fabrics today while waiting for data center Ethernet and its associated ecosystem (adapters, drivers, switches, storage systems) to evolve, your investment should be protected.

Ethernet is a popular option for general purpose networking and is moving forward with extensions to support FCoE and enhanced low-latency data center Ethernet, eliminating the need to stack storage I/O activity onto IP and leaving IP as a good solution for spanning distance or use for NAS or for low-cost iSCSI block-based access co-existing on the same Ethernet. Like it or not, getting Fibre Channel mapped onto a common Ethernet-based converged or unified network is a stepping stone, if not a compromise, between different storage and networking interfaces, commodity networks, experience and skill sets along with performance or deterministic behavior. If nothing else, a converged Ethernet makes for a more comfortable migration from various comfort zones and path of least resistance to a network that IP has been built on.

Near term, putting the pros and caveats aside from traditional storage professionals who have concerns about IP or networking and converted storage professionals who favor IP, FCoE is a step forward. Marketing and fanfare aside, InfiniBand has some legs to stand on for now, but when factoring in business, economic, broad existing adoption and other facts, converged data center class Ethernet becomes a winner. IP is a contender on a longer-term basis beyond its current role of supporting iSCSI, NAS and Fibre Channel over distance (FCIP).

Vendors to Watch

Several vendors have announced initiatives, shown technology proof of concept (technology demonstrations) or actually begun shipping IOV enabling technology. For example Brocade has announced its Data Center Fabric (DCF) initiative. Meanwhile QLogic, NetApp and startup Nuova demonstrated converged network architecture based on FCoE at the fall 2007 SNW in Dallas. Not to be outdone, Cisco has enhanced its InfiniBand line of switches and routers based on the technology acquired from Topspin, and QLogic has updated its Silverstorm-acquired InfiniBand lineup with announcements during the recent Supercomputing 2007 event.

Startup Woven has released a core edge low-latency, high-performance Ethernet switch to support data center class Ethernet deployments. Another startup, Xsigo, continues to gain momentum by deploying IOV solutions enabling virtual HBAs and virtual NICs for any-to-any access of Ethernet networks including IP-based storage as well as Fibre Channel-based SANs. Additional marketing names you can expect to hear more about include converged network adapter (CNA), converged network interface (CNI), service-oriented network architecture (SONA) and unified fabrics, among others.

Storage and I/O adapter, NIC, switch and network chip vendors to keep an eye on include, among others, Brocade, Chelsio, Cisco, Emulex, Intel, Mellanox, Neterion, NetXen, Nuova, OptiPath, QLogic, Voltaire, Woven and Xsigo, along with operating systems, server and storage systems vendors. Also keep an eye on industry trade groups and standards organizations, including ANSI T11, FCIA, FCoE, the InfiniBand trade association (IBTA) and PCIsig.

Wrapping Up For Now

To wrap up, virtual environments still rely on physical resources and infrastructure resource management to exist. Learn to identify the differences between the various approaches of virtual I/O operations and virtual I/O connectivity, along with their applicable benefit to your organization. As with other virtualization techniques and technologies, align the applicable solution to meet your particular needs and address specific pain points while being careful not to introduce additional complexity.

Greg Schulz is founder and senior analyst of the StorageIO group and author of "Resilient Storage Networks" (Elsevier).

Page 2 of 2

Previous Page

1 2