26
circle6 No guarantee for the with such different CEE is not merely a “new
order of the data blocks characteristics? Both serve a Ethernet,” but rather a protocol
transferred (“In-order useful a purpose in their own that meets the needs of both
OGY delivery”) fields of application and have storage networks (SANs) and
circle6 No “Lossless transport” been developed to meet certain classic networks. For this
of data blocks requirements. In computer reason, CEE cannot function in
circle6 No “Acknowledged link centres, both protocols are the the Ethernet infrastructure that
TECHNOL level” dominant network is currently in use in computer
circle6 No “Buffer to buffer environments for their centres.
management” respective fields of application:
circle6 No Name server (SNS) for Ethernet for computer-computer To convert “Standard Ethernet”
recognising and allocating linking and Fibre Channel for to “Converged Enhanced
resources computer-storage linking. Ethernet” (CEE), the previously
circle6 No possibility of defining mentioned requirements of the
zones or distributing However, the ability to use both storage environment must be
resources among zones technologies together, not just absolutely met. At 10 GB/sec,
FIBRE CHANNEL
circle6 No “Remote state change in parallel, would help simplify even the first generation of CEE
notifications (RSCNs)” the network infrastructure, is an extremely fast network.
specifically with regard to More than 16 manufacturers are
Unfortunately, these are cabling. Moreover, just one working with the IEEE and IETF
precisely the characteristics interface on the computer institutions to develop
that are essential for would suffice to connect both standards.
connecting storage systems network and storage
with servers. Because, as capabilities. Due to its high requirements,
explained earlier, the extremely CEE is a complex and therefore
critical SCSI cable is replaced That Ethernet infrastructure, – at least in the foreseeable
by a network. which is so commonly used future – not inexpensive
today, can be used without technology that is principally of
It is also possible to map these modification as network interest to large computer
characteristics in higher infrastructure for storage centres. For smaller and mid-
protocol levels, in what are connections in layers 1 and 2 sized facilities, the classic
referred to as Top Level has already been discussed. Ethernet infrastructure for
Protocols, but this has a However, an improved protocol, computer-computer linking and
significant negative impact on better suited to meet today’s Fibre Channel for computer-
both the overhead and the growing requirements for both storage linking will likely
latency times. environments –that is, remain the dominant
computer-computer and technologies.
It is important that Ethernet not computer-storage networks –
be equated with TCP/IP. could be used instead. One topic that warrants a brief
Ethernet comprises the physical comment here is the physical
and transport levels (layers 1 This improved Ethernet layer. As demonstrated by the
and 2), while TCP and IP protocol is often called 10 GB/sec transfer rate, CEE
comprise higher levels. The “Converged Enhanced Ethernet places different demands on
TCP/IP protocol can thus also (CEE). CEE is, however, not an the physical layer 1 than
be transferred over other initiative from an individual compared with the classic
transport layers, such as Fibre manufacturer (like “Datacenter gigabyte Ethernet. This is
Channel. Ethernet (DCE),” for example) another reason that
but rather a recent step in the implementing CEE requires a
Fibre Channel and CEE progress of technology new Ethernet infrastructure.
Then why make a comparison designed to meet new industry
between two network protocols standards. CEE’s most important
JUNE 09 WWW.SNS-UK.CO.UK
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