Cisco Cisco Nexus 5010 Switch Libro bianco
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of Fibre Channel traffic over Ethernet fabric by encapsulating native Fibre Channel frames into Ethernet packets, as
shown in Figure 2.
Figure 2. In FCoE Packets, the Fibre Channel Payload Is Encapsulated in the Ethernet Header
This approach preserves the native format of Fibre Channel frames, and FCoE traffic appears as Fibre Channel
traffic to the Fibre Channel fabric. This characteristic allows IT departments to maintain the existing environment’s
operations, security, and traffic-management attributes before and after migration; it also preserves investments in
Fibre Channel expertise and equipment.
FCoE enables the consolidation of the LAN and SAN over a common infrastructure that reduces the number of
server I/O adapters and cables, lowers power and cooling costs through the consolidation of server I/O adapters,
and eliminates unnecessary switching infrastructure. With the capability to transport Fibre Channel over Ethernet,
the common infrastructure for storage is in place: 10 Gigabit Ethernet. Although 10Gbps Ethernet provides a solid
foundation for a Unified Fabric, there is one additional characteristic that it must provide to enable the transport of
Fibre Channel over Ethernet and that is lossless operation.
Why lossless 10 Gigabit Ethernet? Lossless Ethernet is a prerequisite for consolidation of Fibre Channel SAN traffic
over a Unified Fabric. A set of network technologies, including IEEE Data Center Bridging, enables Ethernet fabrics
to support lossless transmission, making them suitable for carrying all types of SAN traffic. This set of emerging
standards enables better traffic prioritization over a single Ethernet interface and provides an advanced means for
shaping traffic on the network to decrease congestion. A description of how Cisco Unified Fabric and IEEE Data
Center Bridging enables convergence of different I/O traffic onto a single Unified Fabric in the data centers is
presented in the next section.
Cisco Nexus 5000 Series Switches
Cisco Nexus™ 5000 Series Switches (Figure 3) are the devices in the Cisco
®
data center switch portfolio that deliver
on the promise of a Unified Fabric for the data center. This Unified Fabric will have the operational characteristics to
concurrently handle LAN, SAN, and server clustering traffic. In addition, the Cisco Nexus 5000 Series has a cut-
through design architecture that can deliver a consistent port-to-port latency of 3.2 microseconds independent of the
packet size. The Cisco Nexus 5000 Series’ high performance line rate 10 Gigabit Ethernet throughput characteristic
combined with its low latency enable a outstanding efficiency and performance for storage networks. Low latency
and low jitter are essential requirements for the high-performance computing applications that the Cisco Nexus 5000
Series consolidates over the same Unified Fabric.
Figure 3. Cisco Nexus 5020 Unified Fabric Switch
Consolidating the multiple networks in the data center into a single network will promote significant reductions in
capital and operating expenses. Just as important, giving every server in the data center consistent and ubiquitous
I/O capabilities will markedly improve the service capabilities, flexibility, and resilience of the data center.