Cisco Unified Fabric with FCoE
In modern-day data centers, both LAN and SAN infrastructure are combining and specific equipment for both technologies are available together. Cisco Unified fabric is the convergence of all the various data center I/O technologies over Ethernet One of the most disruptive technologies introduced in the Cisco Nexus family of switches in this area is the ability to transport SAN traffic with Fibre Channel over Ethernet (FCoE).
Generally, FCoE merges LAN with SAN. Fibre Channel over Ethernet, or FCoE, is a storage protocol that enables Fibre Channel traffic to run directly over existing high speed Ethernet infrastructure. It converges storage and IP protocols into a single cable transport and interface. The idea behind the protocol is to consolidate input/output, reduce switch complexity, and cut back on cabled and interference card counts. Essentially, FCoE transmits SAN traffic over the same equipment used for LAN traffic. It works by encapsulating Fibre Channel packets within Ethernet packets, so the packets can then pass over an Ethernet network. This is made possible with a converged network adapter, which combines the functionality of a Fibre Channel adapter and an Ethernet adapter.
Benefits
- Reduced complexity
- Eliminating the need for Fibre Channel switches
- Increased performance
- Leveraging inexpensive Ethernet networks with speeds up to 40 gigabits per second
- Simplified network management using pre-existing Ethernet network tools to manage storage traffic
This will cause the high reduction in the number of different server adaptors that are required to be managed and bring simplification in cabling. Unifying the traffic will also provide taking advantage of the robust layer 2 domains with complete multi-path capabilities and enable using of virtual port channels and Cisco’s Fabric Path technologies. Moreover, total cost of ownership (TCO) will be reduced because of this unified equipment instead of separate LAN and SAN equipment.  While it works with standard Ethernet cards, cables and switches, it requires the use of end-to-end FCoE devices. FCoE is primarily used within organizations looking to drive down costs by avoiding expensive Fibre Channel switches, as well as the associated management costs, or those that don’t want to invest in modern Fibre Channel hardware.
Converged network adapter
A converged network adapter (CNA) is a single network interface card (NIC) that includes both a Fibre Channel (FC) host bus adapter (HBA) and a TCP/IP Ethernet NIC. It connects servers to FC-based storage area networks (SANs) and Ethernet-based local area networks (LANs).
The CNA connects to the server via a PCI Express (PCIe) interface while the server sends both FC SAN and LAN and traffic to an Ethernet port on a converged switch using the Fibre Channel over Ethernet (FCoE) protocol for the FC SAN data and the Ethernet protocol for LAN data. The converged switch converts the FCoE traffic to FC and sends it to the FC SAN. The Ethernet traffic is sent directly to the LAN.
In networks without CNAs, servers have to have at least two adapters: One with a FC HBA to connect the server to the storage network, and another with a TCP/IP Ethernet NIC to connect the server to the LAN.
Using a single CNA to connect servers to storage and networks reduces costs by requiring fewer adapter cards, cables, switch ports, and PCIe slots. CNAs also reduce the complexity of administration because there is only one connection and cable to manage.
Unified Fabric Requirements
While LAN packet loss is commonly happening but SAN can’t deal with any packet loss, so to achieve FCoE architecture there needs to be a lot of requirements to be met. The first one is the entire Fibre channel frame required to be carried in the payload of a single Ethernet frame called Jumbo frames. Jumbo frames are Ethernet frames with more than 1500 bytes of payload, the limit set by the IEEE 802.3 standard. Commonly, jumbo frames can carry up to 9000 bytes of payload, but smaller and larger variations exist and some care must be taken using the term.
Also, Port worldwide names is required to be able to map to MAC addresses that are used in an Ethernet environment. Moreover, additional protocol to handle login of Fibre channel devices across a unified fabric is needed. FIP is Fibre Channel over Ethernet initialization protocol.
Finally, lossless delivery in the ethernet environment is mandatory which means no packet loss at all. To fulfill these requirements minimum of 10 Gbps as the technology is expected.
Cisco Unified Fabric Solutions
Evolutionary approach to LAN and SAN convergence Makes it easier for data center managers to meet the day-to-day needs of the evolving network while freeing time and resources to focus on strategic activities that benefit the business. With LAN and SAN networking solutions both provided through:
- Cisco Nexus
- Cisco MDS 9000 Family portfolios
you can use a common operating system (Cisco NX-OS Software) and benefit from single-pane management with Cisco Prime Data Center Network Manager (DCNM).
All These products support Cisco Smart Licensing and by connecting to CSSM website all product instances would be registered. Also, Cisco Nexus PLR licenses are available to active all features forever without Internet connectivity for highly secure environments.
