THE INVISIBLE UPGRADE: MOVING TO 1Gbps

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1 READ ABOUT: Decreasing power consumption by upgrading from older 24-port 1U switches to 48-port 1U switches Monitoring Gigabit Ethernet for error rates and link speeds More access points with lower power levels on new wireless deployments Auditing equipment upstream of the wiring closet for hidden bottlenecks Network hardware is only the (easy) start for supporting 1Gbps desktop THE INVISIBLE UPGRADE: MOVING TO 1Gbps 8

2 CDW.COM/NETWORK-SOLUTIONS Network equipment manufacturers are dropping 10/100 megabits-per-second gear out of their switch product lines and moving to 10/100/1000Mbps in newer products. At the same time, wireless speeds jumped over the 100Mbps barrier when IEEE n was released in Today, speeds are pushing 1 gigabit per second (Gbps) with the IEEE ac wireless standard, which starts at 80Mbps and can achieve up to 867Mbps in even low-end configurations, depending on factors such as the width of the wireless channel a network uses. In reality, enterprises get Gigabit Ethernet speeds by default in virtually everything they buy, from notebooks and desktops to switches, firewalls and routers. All of this should add up to an invisible, free upgrade of enterprise networks from 100Mbps to 1000Mbps as equipment is cycled and replaced, right? Yes and no. The equipment itself may not be a budget-buster, but IT managers have to worry about other issues, including: Power and cooling in the wiring closets Power over Ethernet (PoE) requirements Port density and in-closet cabling; wiring, cabling and link monitoring Uplink speeds out of wiring closets Wireless devices Upstream hardware (security devices such as firewalls, core switching and routing) Organizations looking to bring the benefits of Gigabit Ethernet desktop speeds to end users wired and wireless devices should consider these issues in their infrastructures to determine how challenging a Gig-E upgrade might be. POWER & COOLING In most circumstances, upgrading to Gig-E speeds won t dramatically change power and cooling requirements in wiring closets. Gigabit Ethernet ports do require more power to run than 100Mbps ports, but this increase is not significant for most building sizes and switch configurations. However, some factors can alter the equation, including changing vendors, densities, Voice over IP (VoIP), wireless and port usage levels. Network managers upgrading from older 24-port 1U switches to 48-port 1U switches will see a decrease in per-port power consumption, noise and cooling requirements, stemming from efficiency improvements tied to using fewer power supplies and cooling systems. When all ports in all offices are always connected, the decrease in units is easy to calculate. But for network designs where not every port is active all the time, installing higher-density switches may be an opportunity to increase the number of connected ports reducing expensive move/add/change (MAC) costs down the line with a small capital investment up front. In this case, the jump from 24-port units to the same number of 48-port units will increase demand for power and cooling by about 50 percent (while doubling the number of ports). Gig-E projects that are combined with VoIP or expanded wireless (both of which call for a lot of PoE or PoE+ equipment) are more complicated. Certainly, power consumption in the wiring closet will increase, as VoIP and Wi-Fi equipment call for PoE switches. A 48-port switch running half its ports with PoE will draw more than 10 times as much power as the same switch without PoE. If all the ports have PoE devices, the switch draws 20 times the power of a non-poe switch. Jumping from a power budget of about one ampere per switch to 5 to 10 amperes per switch can be an expensive change, especially if new wiring is required to the wiring closet. Fortunately, the extra power doesn t all have to be accounted for in the cooling budget. With PoE, some increase in heat load occurs within the wiring closet, but most of the heat is dissipated where the electronic devices are at the phone or wireless access point outside of the wiring closet. PoE & THE VoIP PROBLEM PoE is most commonly used for VoIP phones, Wi-Fi access points and security cameras, although other products (such as environmental controls to PoE-powered Network Time Protocol-synchronized wall clocks) are showing up in building networks. With PoE (IEEE 802.3af, about 15 watts per port) giving way to PoE+ (IEEE 802.3at, about 30W per port), enteprises are likely to see increasing use of high-powered PoE in even more network devices. > 9

3 Choosing between PoE and PoE+ is simple: Choose PoE+. Complications to PoE come when VoIP is included, because of the sudden doubling of the number of network devices. Ideally, a new VoIP phone would be connected separately to the network, just as the phone it replaced ran on a separate PBX line. If the network administrator was sufficiently forward-looking to run CAT 5 or CAT 5e (or even CAT 3) cabling for the phones, the change is easy. The only issue is the doubling of the number of Ethernet ports in the wiring closet. But many network managers have their hands tied and cannot use the phone wiring. In rare cases, sufficient Ethernet cabling is already in place. But more often, the existing Ethernet network now has to double up: One cable has to serve both the VoIP phone and the end user s wired workstation. Port splitting (taking the four pairs of a typical Ethernet cable and using two pairs for one connection and two for the other) won t work with Gigabit Ethernet, which requires all four pairs. VoIP phone manufacturers Organizations may find it more cost-effective and flexible to increase wiring in underserved areas rather than bump up the cost of a VoIP station. solved this problem by putting small switches into their phones. Plug the phone into the PoE switch, then plug the workstation into the phone, and both devices are on the network. But in this scenario, the phones must have Gig-E switches on them, which can significantly increase the cost per phone. Organizations may find it more costeffective and flexible to increase wiring in underserved areas of the building rather than bump up the cost of a VoIP station. CABLING & MONITORING New in-building installations should aim for new CAT 6-compliant cabling plants, but few networks have such up-to-date wires in their walls. Making the Gig-E bump to the desktop may require a close assessment of wiring, and some compromises. A simplistic view of cabling says that CAT 5 is good for 10/100 Mbps, CAT 5e for 10/100/1000 Mbps and CAT 6 for 10 Gig-E. This may work as a rule of thumb, but reality is different, and many CAT 5 cable plants will handle Gig-E just fine without an expensive rewiring project. One of the bigger differences between CAT 5 and CAT 5e is that CAT 5 cabling, designed for 100Mbps applications, should make all four pairs available, while CAT 5e cabling, designed for 1Gbps applications, must make all four pairs available. Port splitters or bad pairs immediately disqualify a CAT 5 cable installation from Gigabit Ethernet speeds. 10 Gigabit, 40 Gigabit and Beyond in the Data Center If desktop speeds are jumping to 1Gbps, what does that mean for servers and the network core? Generally, IT managers should expect a gradual shift in server hardware from 1Gbps to 10Gbps over the next few years. These speeds are primarily needed in virtualization environments, but the heavy use of virtualization means that servers are shifting to faster networking capabilities overall. Using top-ofrack switches, copper 10 Gigabit Ethernet will be a cost-effective and easy change from existing technologies. When servers are at 10Gbps, administrators should consider uplink speeds from server cabinets and top-of-rack switches. For Ethernet, the next jump up is 40Gbps. However, 40Gbps in a data center (short range) is not simply 10Gbps running at four times the speed. Indeed, 40 Gigabit Ethernet is actually four 10 Gig-E channels, all physically bound together. This calls for expensive patch cables (instead of two fibers, most have eight or 12) and new connectors to handle the increased number of fibers, as well as higher-capacity backplanes and line cards. Further, 40 Gigabit Ethernet is also fiber-only at this stage, making for a more delicate connection between network devices. The jump to 40Gbps (or the next step after that, 100Gbp) between top-of-rack switches and data center cores is inevitable. In 2014, enterprises should steer clear of 40Gbps except where absolutely necessary, because both standards and products are still being set. Innovations, such as new bidirectional (BiDi) optics that use existing patch infrastructure for 40Gbps, can reduce total costs and simplify deployment. 10

4 CDW.COM/NETWORK-SOLUTIONS Network administrators should test the cable plant, looking at bad pairs and possibly excessive crosstalk, before deciding whether to support Gigabit Ethernet. The failure of a few cables doesn t mean that the whole building must be rewired. It s much cheaper to fix a few bad spots than to swap them all out. Another important step is to look at the patch panels and patch cables in use. In-wall cabling is just one part of a structured cabling system. Patch panels in the wiring closet and jacks in each office are part of the cabling system. Sometimes, replacing in-closet patch cables, reterminating existing cable on a CAT 5e patch panel, and replacing office jacks are sufficient to reduce crosstalk and reach Gigabit Ethernet speeds. Neither poor patch cables nor sloppy termination may have been an issue at 100Mbps speeds, but they will cause problems with Gig-E. When running Gigabit Ethernet over any cabling plant (not just an old one), it s important to keep an eye on error rates and link speeds. Ethernet is designed to lose some packets, but not many. And if a particular port has a high error rate, this will cause severe problems with network performance. Automated tools that look at hundreds or thousands of ports for errors should be an integral part of any Gig-E upgrade project. The port counters don t have to be scanned every few minutes, but a tool that checks error counts daily or even weekly can alert administrators to problems that are otherwise hard to debug. At the same time, link speeds should be monitored. Any port that connects using half-duplex is suspicious and needs to be investigated, along with any port at speeds less than 100Mbps. While the occasional old printer may have a 10Mbps Ethernet jack, most half-duplex or low-speed connections 58% NETWORKS WILL NEED TO SUPPORT 58 PERCENT COMPOUND ANNUAL GROWTH RATE TO MEET DEMAND INCREASES FROM USERS, ACCESS METHODOLOGIES, ACCESS RATES AND SERVICES SUCH AS VIDEO ON DEMAND AND SOCIAL MEDIA UP TO 1 TERABIT PER SECOND IN 2015 AND 10 TERABITS PER SECOND BY SOURCE: IEEE Launches Study Group to Explore 400 Gb/s Ethernet (IEEE, April 2013) point to either an equipment problem or an installation problem, such as placement of a 10Mbps hub between a workstation and the network. UPLINK SPEEDS With an increase in desktop speed, enterprises will also want to bump up the uplink speed from their wiring closets. The easiest option is to go to 10 Gig-E, the next increment in Ethernet, and a conceptually easy changeover for many networks if the fiber will support it. Older fiber has limited ability to handle 10 Gig-E speeds over distances. The standard OM1 cable that is common in most networks (62.5/125 multimode fiber, usually orange-jacketed) will run 10 Gig-E only at distances of about 30 meters. OM3 cable (the aquajacketed type) gives 300 meters. If an organization needs a fiber upgrade but cannot make one, there are other options for increasing uplink speed. Multiple 1Gbps ports can be bound into a link-aggregation group, a very effective way of adding capacity without rewiring, when lots of stations are involved. If each wiring closet has multiple virtual local area networks in use, then migrating to per-vlan Spanning Tree (PVST) gives a primitive type of load balancing, allowing different VLANs to run over different 1Gbps uplinks. IT managers should also examine in-closet uplink speeds. If multiple switches are used in a wiring closet, the interswitch connections should use high-speed links, such as dedicated stacking ports (the best option) or links that operate at greater than 1Gbps. This poses challenges when changing from older blade-type switches to the more cost-effective 1U devices available today, as interswitch uplinks are new when changing in-closet architectures. Although latency between workstation and application is usually not a significant issue, the IT team should aim to eliminate hops by flattening topologies within wiring closets wherever possible. WIRELESS REQUIREMENTS IT managers looking to increase their wireless footprint and enable mobility and bring-your-own-device initiatives can also benefit from Gig-E and PoE upgrades in the wiring closet. Wireless access points jumped above 100Mbps speeds long ago with the introduction of IEEE n equipment and are going above 1Gbps with IEEE ac Wi-Fi gear. Enterprise-class wireless deployments call for more access points with lower power levels to boost wireless speeds and reduce channel contention. They also require more Gig-E ports, more PoE+ ports and > 11

5 more bandwidth in the wiring closets. Bandwidth requirements for wireless can be hard to predict. Many of the wireless devices in a typical building will be smartphones and tablets, which generally do not stress traffic levels. However, meeting rooms with notebook users and wiredreplacement projects bring much higher throughput requirements. For organizations, some things are certain: Demand for wireless is not going away, and bandwidth requirements are not shrinking. Therefore, engineering for higher-speed connections out of the wiring closet, both downstream to access points and upstream to the network core, is a good idea. Wireless devices are also the first to really require IEEE 802.3at s PoE+ power levels. In n and ac, many of the bandwidth increases come from multiple radios operating at once to increase overall throughput, even to a single station. The n standard allows for as many as four spatial streams, which translates into two or three times the power requirements for high-speed access points. The ac standard goes even further, with as many as eight spatial streams, even though current notebooks are shipping with either two or three streams today. All of this adds up to more power than the approximately 15W that standard PoE can deliver, and a need for PoE+ (approximately 30W of 48-volt DC power) in all future wireless equipment. UPSTREAM (AND DOWNSTREAM) HARDWARE As speeds increase in wiring closets, network managers should conduct an audit of all equipment upstream of the wiring closet, as hidden bottlenecks or unaccounted-for components can create performance blocks. Link speed is the most obvious factor to check. Where possible, link speeds should not jump between 1Gbps and 10Gbps more than absolutely necessary and any component still running at 100Mbps is in obvious need of replacement. When 1Gbps and 10Gbps meet in a device, traffic bursts on the 10Gbps side may overwhelm the 1Gbps links. The simplest way to reduce the likelihood of lost Ethernet frames is to provide sufficient buffering in the switches that adapt between 1Gbps and 10Gbps links, and to make sure that no more than one down-speed link (a transition from 10Gbps down to 1Gbps) exists between the core of the network and a desktop user. Generally, buffering at that speed is expensive, which means that the amount of buffer space in each switch will account for cost differences between product lines and vendors. IT managers should look for a minimum of 128 kilobytes of buffer per port on the user side of the network (wiring closets), with 1 megabyte of buffer per port on the server side of the network. In addition to link speed, IT staff should also audit all middle boxes firewalls, intrusion prevention systems and similar equipment to make sure they have sufficient capacity to handle the increase in load. 12