Tag: ethernet

Cisco EnergyWise fundamentals

Cisco EnergyWise is a key part of the Borderless Network concept. According to this document:

The network discovers Cisco EnergyWise manageable devices,
monitors their power consumption, and takes action based on business rules to reduce
power consumption. EnergyWise uses a unique domain-naming system to query and
summarize information from large sets of devices, making it simpler than traditional
network management capabilities. Cisco EnergyWise’s management interfaces allow
facilities and network management applications to communicate with endpoints and
each other using the network as a unifying fabric. The management interface uses
standard SNMP or SSL to integrate Cisco and third-party management systems

I know, I know you will say that it’s a lot of marketing and this is typically for Cisco, but let’s be fair. Tell me one company that is not marketing their product. It’s true that Cisco is quite aggressive in their campaigns, but we have to admit that many times the quality of the products meet our expectation.

Back to EnergyWise, I was lucky enough to have my question taken and being discussed in the live Cisco Borderless Network phase 2, European presentation, on 18th of March. I was curios about the following thing. The Phase 2 campaign was oriented on the power and energy saving, by controlling a lot of device power remotely and being able to shutdown an entire environment when it’s not needed. I asked how will Cisco EnergyWise accomplish this? Either controlling the power outlet in which a device (e.g. laptop) is connected or directly OVER the Ethernet wires.
Their answer was that in the moment Cisco is working closely with the companies that develop network cards, to make this compatible with EnergyWise to be able to power the device over the Ethernet wires. I know about PoE, but PoE is something different and I’m sure that it does not offer enough energy to power up a laptop.
When the recording of the live session will be available, I sure hope to get it and to posted here. In the meantime, I found a very nice explanation of the EnergyWise fundamentals from TechWiseTV. Enjoy it:

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Other Cisco Borderless Networks Related Articles in Internet

Category 6 UTP

Category 6 cable, usually Cat-6, is a cable standard for Gigabit Ethernet and other network protocols that is backward compatible with the Category 5/5e and Category 3 cable standards. The main difference between Cat-6 and it’s previous versions is that CAT-6 fully utilizes all four pairs. Cat-6 features more stringent specifications for crosstalk and system noise. The cable standard provides performance of up to 250 MHz and is suitable for 10BASE-T / 100BASE-TX and 1000BASE-T / 1000BASE-TX (Gigabit Ethernet). It is expected to suit the 10GBASE-T (10Gigabit Ethernet) standard, although with limitations on length if unshielded Cat 6 cable is used.

The cable contains four twisted copper wire pairs, just like earlier copper cable standards and when used as a patch cable, Cat-6 is normally terminated in 8P8C modular connectors. Some Cat-6 cables are too large and may be difficult to attach to 8P8C connectors without a special modular piece and are technically not standard compliant. If components of the various cable standards are intermixed, the performance of the signal path will be limited to that of the lowest category. The maximum allowed length of a Cat-6 cable is 100 meters.

The cable is terminated in either the T568A scheme or the T568B scheme. It doesn’t make any difference which is used, as they are both straight through:

t586b-schemet586a-scheme

Crossover is used for hub to hub, computer to computer, wherever two-way communication is necessary. All gigabit ethernet equipment, and most new 10/100Mb equipment, supports automatic crossover, meaning that either a straight-through or crossover cable may be used for any connection. However, older equipment requires the use of a straight-through cable to connect a switch to a client device, and a crossover cable to connect a switch to a switch or a client to a client. Crossover cables can be constructed by wiring one end to the T568A scheme and the other end with the T568B scheme. This will ensure that the Transmit (TX) pins on both ends are wired through to the Receive (RX) pins on the other end.

If you are starting to build a LAN network now, it’s recommend to use already CAT-6 as it can accommodate most of the usual traffic in a network based on the fact that already NIC cards are build for the speed of 1Gbps. Some useful tips regarding the use of CAT-6 and any Ethernet cable are:

– Do run cables over distances up to 100 meters with their rated speed
– If you know how to handle some cabling tools, do make your own cable if you need lots of varying lengths
– Don’t order anything less than Cat. 5e cable
– Don’t crimp or staple cable, this can easily cause breaks in the cable which are sometimes hard to track down
– Ethernet cables are not directional in any way, you cannot install one backwards
– Lighter colored cables are usually a better choice for two reasons: They are easier to see in the dark, and it’s easier to read the cable catogory stamped on the side
– Use a patch cable when connecting a computer to a router or hub, use a cross over cable when connecting two computers directly together
– If it’s possible and you know that you need higher speed that 100Mbps do not mix different type of cables on the same network segment
– Even if all the specification are saying that the CAT-6 is protected against external factors, do not mount this cables close by cable power or any other cable that can influence the performance of Ethernet cable.

Below you can find a presentation of CAT-6 “how-to” thanks to Giganet:

[flashvideo filename=https://ipnet.xyz/vid/hardware/archive/2009/04/Category6UTPTermination.flv image=https://ipnet.xyz/vid/hardware/archive/2009/04//Category6UTPTermination.jpg width=486 height=412 /]

Resources used:
http://donutey.com/ethernet.php
http://en.wikipedia.org/wiki/Category_6_cable
http://en.wikipedia.org/wiki/TIA/EIA-568-B

Is it time to cut the Ethernet access cable?

A range of companies with wireless LANs are discovering that 50% to 90% or more of Ethernet ports now go unused, because Wi-Fi has become so prevalent.

They look at racks of unused switches, ports, Ethernet wall jacks, the cabling that connects them all, the yearly maintenance charges for unused switches, electrical charges and cooling costs. So why not formally drop what many end users have already discarded — the Ethernet cable?

“There’s definitely a rightsizing going on,” says Michael King, research director, mobile and wireless, for Gartner. “By 2011, 70% of all net new ports will be wireless. People are saying, ‘we don’t need to be spending so much on a wired infrastructure if no one is using it.”

Many of these issues were predicted in fall 2007 by Burton Group Analyst Paul DeBeasi, in a report provocatively titled “The end of Ethernet?” In it, he argued that the demand for mobility and the advent of 802.11n networks with shared throughput of 150M to 180Mbps would lead enterprises to cut the Ethernet access cord. (See our Clear Choice Test of four 802.11n vendors’ gear.)

Read the full article on NetworkWorld.com…