With the bandwidth migrating from 100M Ethernet to 1/10 Gigabit Ethernet (GbE), large enterprises have also been migrating their data center infrastructures accordingly. 10GbE technology has now been very mature and 10GbE in the data center is very common now. There are many interfaces options for 10GbE, such as SFP+ fiber, CX4, SFP+ direct attach copper (like HP J9281B SFP+ passive direct attach copper cable, or HP JG081C SFP+ passive direct attach copper cable), and 10GBASE-T. Among them, which one will you choose? Each one has its own advantages and disadvantages. In this post, we will talk about why choose 10GBASE-T in 10GbE data center migration.
Disadvantages of SFP+ in 10GbE Data Center
SFP+ has been adopted on Ethernet adapters and switches and supports both copper and fiber optic cables, which makes it a better solution than CX4. However, SFP+ optical transceiver (such as Cisco SFP-10G-LR-S 10GBASE-LR SFP+ transceiver) is not backward-compatible with the twisted-pair 1GbE broadly deployed throughout the data center. SFP+ connectors and their cabling were not compatible with the RJ-45 connectors used on 1GbE networks. Enterprise customers cannot just start adding SFP+ 10GbE to an existing RJ-45 1GbE infrastructure. New switches and new cables are required, which is a big chunk of change.
Advantages of 10GBASE-T in 10GbE Data Center
10GBASE-T is backward-compatible with 1000BASE-T, it can be deployed in the existing 1GbE switch infrastructures in the data centers that are cabled with CAT6, CAT6A or above cabling. As we know, 1GbE is still widely used in data center. Thus, 10GBASE-T is a great choice for gradual transition from 1GbE deployment to 10GbE. Other advantages of 10GBASE-T include:
Like all BASE-T implementations, 10GBASE-T works for lengths up to 100 meters, which gives IT managers a far-great level of flexibility in connecting devices in the data center. 10GBASE-T can accommodate either top of the rack, middle or end of the row network topologies, giving IT managers flexibility in server placement since it will work with the existing structured cabling systems.
The challenge with 10GBASE-T is that even single-chip 10GBASE-T adapters consume a watt or two more than the SFP+ alternatives. More power consumption is not a good thing in the data center. However, the expected incremental costs in power over the life of a typical data center are far less than the amount of money saved from reduced cabling costs. Besides, with process improvements, chips improved from one generation to the next. The power and cost of the latest 10GBASE-T PHYs will be reduced greatly than before.
Another challenge with 10GBASE-T is whether it could deliver the reliability and low bit-error rate of SFP+, or whether the high demands of FCoE could be met with 10GBASE-T. Cisco has announced that it had successfully qualified FCoE over 10GBASE-T and is supporting it on its newer switches that support 10GBASE-T in 2013.
10GBASE-T has a low latency range, from just over 2 microseconds to less than 4 microseconds. Latency for 10GBASE-T is more than 3 times lower than 1000BASE-T at larger packet sizes. Only the most latent sensitive applications such as HPC or high frequency trading systems would notice any latency.
When it comes to the cost, copper cables offer great savings. Typically, passive copper cables are two to five times less expensive than comparable lengths of fiber optic cables. In a 1,000-node cluster, with hundreds of required cables, that can translate into hundreds of thousands of dollars. Extending that into larger data centers, the savings can reach millions. Besides, copper cables do not consume power and because their thermal design requires less cooling, there are extensive savings on operating expenditures within the data center.
Conclusion
10GbE standards are very mature and reliable now. 10GBASE-T can save you a lot and at the same time provide you with easy cable installation. 10GBASE-T can also be backwards compatible with 1GbE networks, offering investment protection. Deployment of 10GBASE-T will simplify the networking transition by providing an easier path to migrate to 10GbE infrastructure in support of higher bandwidth needed for virtualized servers.
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