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September 26, 2007

What's an SMB?

I love Wikipedia. I just do – it just speaks to me. So of course I had to check out the Wikipedia definition of SMB. Lot’s of interesting possibilities including Small Mouth Bass, Steve Miller Band, Server Message Block protocol. Plus some of which are just way too inappropriate to mention. Here’s a liberally paraphrased version of the Wikipedia definition I was after:

“Small and medium enterprises or SMEs are companies whose headcount or turnover (revenue) falls below certain limits. The EU categorizes companies with fewer than 50 employees as "small", and those with fewer than 250 as "medium". In the US, SMB often refers to companies with less than 100 employees, while medium-sized business often refers to those with less than 500 employees.”

Cisco defines SMB pretty much along the lines of the EU definition. These definitions are fairly meaningless because they imply that SMBs are just small enterprises. But thinking in terms of mobility, small and medium size companies are different than enterprises in 3 key ways:

1) Applications that drive their wireless deployments and upgrades aren’t voice, guest, or location tracking. They are more basic such as moving from paper to electronic systems (e.g. electronic medical records), upgrading accounting systems, and addressing regulatory compliance. Or deployments are event driven such as moving to a new location or addressing security holes.

2) They speak a different language then enterprise. SMB owners and business managers rely on a range of “experts” for IT decisions because they typically have little or no IT staff. IT staff that exists are generalists, not networking or wireless experts. Trusted advisors may include business peers, vendors (think Dell), on-line retailers such as CDW, accountants, consultants, and brothers-in-law.

3) SMBs don’t really know how Cisco can help their business. To most SMBs and their VARs, Cisco is too big, too complex, and too expensive. Try navigating Cisco.com and compare the experience to hp.com. This is our opportunity and this is what we need address.

I have to admit that all of this is pretty much a U.S. centric point of view and needs more thinking for different markets. In many countries, a 250 or even 100 person company is a big business. And even though we like to segment the market by company size, how many SMBs actually view themselves as one? They would most likely describe their business as (for example) a manufacturer, retailer, medical clinic, hotel, legal office - and we should too.

Posted by Georganne Benesch at 06:42 PM Permalink | Comments (1) | TrackBacks (0)

September 19, 2007

Defining the Enterprise Mobility Network

Given my role as CTO for the Ethernet and Wireless Technology Group, I am frequently asked how Ethernet relates to mobility. While this is a great question, I typically ask whether they have ever connected to an Ethernet cable other than the one in their office - and, of course, you already know the answer. Mobility itself has many forms, including being nomadic, which is typically how most people use both wireless and wired networks with laptops/notebooks.

Today's wireless networks have evolved to the point where strong user authentication is used to ensure that users are provided the proper level of access based on their role in the organization. More often than not, what I am hearing is that once a wireless network has been deployed, and the user/policy mappings have been defined, network managers would like to leverage that existing base for their wired networks as well. Imagine how much simpler it would be to deploy a network if it was no longer necessary to know apriori who/what was connected to each individual switch port, and simply let the network apply the proper policy and route/isolate the traffic accordingly.

I saw a recent study where a number of IT professionals were asked about their plans for deploying Network Admission Control (NAC). One of the questions in this survey asked whether they had plans to provide NAC services on the wired or wireless network? I think the reason why I was perplexed by this question was that someone could believe their devices would be 'non-compliant to their corporate policy' only when connecting through a specific network.

In the end, it's really about One Network. Users will roam throughout the enterprise and expect a seamless user experience as well as the same level of service, regardless of whether they are on the wireless network, or conected to any Ethernet jack they can find. So while you may be asking yourself how Ethernet relates to mobility, your users already know the answer.

Posted by Pat Calhoun at 03:20 PM Permalink | Comments (0) | TrackBacks (0)

September 17, 2007

Your Network's Worst Enemy

Wireless networks have matured to the point where security is no longer their primary concern. More and more I am hearing from customers that their primary issue these days is interference.

Interference is one of those things that is really tricky to both identify and resolve. There are few IT geeks out there that I've met, who happen to understand networking and the complexity of radio frequencies. In fact, I wouldn't be surprised if most people reading this blog entry have never even seen a spectrum analyzer. I know I have, but it has to be a very bad day when I need to turn one on... It is in fact for this main reason that as we designed the unified Wireless LAN controller - to take the science out of RF and try to provide more visibility in a manner that most networking experts understand. We turned that complex spectrum analyzer into a graph that would show the health of the network, by showing both interference (other 802.11 traffic) and noise (non 802.11 traffic). We've heard consistently from our customers how much they appreciate getting a better understanding of their network.

The past year has been a very exciting time for us in the Wireless LAN business, as we've seen the technology grow from a convenience to a mission critical network. Ironically, while I think we all agree of the importance of this network, most IT managers would still prefer to treat it as a secondary network - and I believe that this is mostly because the science behind RF makes it a very difficult network to troubleshoot. What does one do when excessive noise shows up? It's not quite like calling your neighbor and asking them to turn down the Deep Purple they've been blasting since 9PM (ok... I'm showing my age... these days you'd probably be complaining about Linkin Park). The expertize, and equipment, required to identify the source of noise is so complex that most people simply leave it alone - but this is becoming more of a problem as more of these devices are introduced in your network, while your users expectations of the network increases.

As we were designing the WLAN unified system, we quickly came to the conclusion that trying to identify the source of "noise" would be nearly impossible for most customers, and this was in fact the impetus for creating our Radio Resource Management (RRM) system. RRM is a set of algorithms that are run to optimize the configuration of the various radio parameters to increase the system's performance (for those that are interested, I will write a piece of RRM in a future blog). RRM certainly solved many of the issues in our customer's networks, by reconfiguring the network to move away from a source that is harming the performance of the network. Ultimately, we need to start thinking about how we can provide more visibility into what is causing the noise - and remove these interferers to help regain some sanity in our air space.

Posted by Pat Calhoun at 06:43 AM Permalink | Comments (8) | TrackBacks (0)

September 10, 2007

What is Enterprise Ready WLAN?

Has anyone noticed the large number of "enterprise class" wireless devices being delivered to the market that only support the 2.4Ghz spectrum?

Whether these devices support 802.11b or 802.11g, the fact remains that there is simply not enough spectrum available in 2.4Ghz space to ensure a quality service. As many of you probably already know, the 2.4Ghz space only supports three non-overlap channels, and no matter how creative your channel plan is, any deployment that exceeds three APs will see some co-channel interference - including from devices that may not be under your control (is your neighbor running a network?).

Backgrounder: co-channel interference means that two neighboring APs share the same channel. When this occurs, if any device in either cell transmits, it is likely to create interference in the other cell. Adjacent channel interference means that neighboring access points are on channels that follow each other. In these cases, physical distance and radio quality can cause some bleed over across the channels and create interference. So in a reason that in an ideal network, you want to ensure that neighboring APs do not share the same channel, and the channel spacing eliminates adjacent interference.

Going back to the 2.4Ghz spectrum, with a total of three channels, you can now see that eliminating co-channel interference is a challenge, while eliminating adjacent interference is simply not possible.

It is for this reason that enterprises need to start considering moving to the 5Ghz spectrum. The number of channels in 5Ghz ensures that sufficient spacing can be established between the APs to eliminate both co-channel and adjacent channel interference. What I would recommend is that in your purchasing decisions you make sure that the devices support 5Ghz. I've heard many arguments from device manufacturers that 5Ghz WiFi is simply too power hungry. I would point those manufacturers to Cisco's 7921 WiFi phone, which has an impressive stand-by and talk-time battery life. We've reached a point where technology is simply no longer a reason for ignoring enterprise spectrum demands.

Many customers have asked whether they should dedicate their 5Ghz spectrum for voice, and push all data to 2.4Ghz. Given the sensitvity of voice service, and the fact that poor performance is much more noticeable to the user, it is a reasonable approach. For customers that deploy dedicated voice devices, such as the 7921 mentioned above, enforcement may be possible. However, for most customers I believe this is an interim step since multi-mode devices are now becoming widely available. These devices provide both Unified Communications and data services, making it very difficult to dedicate a single spectrum for voice - and causing both data and voice on the 5Ghz band.

So if I have both data and voice services on my 5Ghz band, how will I ensure the voice quality meets my user's expectations? As we are seeing through the WiFi certification process, more voice devices are now being certified to be WMM compliant. The WMM certification process provides quality of service (QoS) enhancements to ensure that voice traffic is properly prioritized. I believe that over time WMM will also become an "Enterprise Ready" requirement.

Posted by Pat Calhoun at 10:47 AM Permalink | Comments (0) | TrackBacks (0)

September 06, 2007

What's up with MIMO?

With all of the recent talk about 802.11n, I am frequently asked to explain what is MIMO and its benefits. I suspect this may require a few blog sessions, so today I thought I'd focus on multipath and antenna configurations.

So what's up with 3 transmitters and 2 receivers??? Given how much I enjoy music, let me use home audio as an analogy. Remember the days of mono speaker systems (yeah, I know... I'm dating myself somewhat here). Well, in a mono system, the audio system sends all of the audio signals through a single speaker. The sound takes the fastest path to the listener, which I would claim in most home environments would be direct line of sight. While this does provide a full audio experience, there is no directionality in the sound which lessens the entertainment experience. And here is where 5 channel digital audio comes into the picture. In such setups, you will have three front speakers; center, left and right. First off, you will notice a similarity between MIMO and home audio technologies, since there are three front speakers, but most listeners that I know are restricted to two ears. Of course, the question that remains is whether lack of a third ear on our forehead decreases the total experience. These three speakers send independent audio signals, each with directional sensitivity. If a plane is moving from the left to right of the screen, the sound will match.

Unfortunately, that's where the comparison of MIMO and audio systems will end. As with the audio example, an 802.11n access point has multiple antennas, and they are typically referred to in terms of transmitters and receivers. So when you hear about a 3x2 802.11n device, this would mean three transmitters and two receivers. However, unlike the audio system which sends a different audio stream on each front antenna, each transmitter in the 802.11n access point transmits the same signal. So why bother sending the same signal on multiple antennas? Well... here's where WLAN also differs from a typical audio system. Most audio systems are used in a single, typically square or rectangular room, which provides for an optimal experience. However, an 802.11 home network is expected to be available throughout the home, and this requires the signals to traverse through various building materials, including walls and doors. Interestingly enough, much to my mother's dismay, when I was young I also seemed to think audio should be enjoyed in a similar manner.... but that's another story.

Going back to WLANs, office environment have many metal obstructions, including filing cabinets and but also building materials found in walls, ceilings and even door frames. These metalic materials do not absorb the signal and therefore cause it to be reflected, and unlike the human ear, electronics are much more sensitive to reception delays. These reflections are called multipath, which historically would significantly hamper network performance because a single antenna would receive multiple reflected signals at different times - causing receiver interference. However, since an 802.11n device has multiple antennas, the separation between these antennas causes the multiple signals to follow a different path to the receiver, basically using the properties of multipath to its advantage. These signals are then received on multiple antennas, which is where the magic of MIMO comes in. These multiple received signals are recombined into a single stream to increase the strength of the signal.

Well... I gotta run so next time maybe we can talk about what happens when that third ear grows on your forehead.

PatC

Posted by Pat Calhoun at 07:37 AM Permalink | Comments (3) | TrackBacks (0)

September 03, 2007

802.11n -- Why now, why not?

There has certainly been a good deal of industry discussion, or should I say a good dose of vendor hype, around the new emerging standard for Wi-Fi, 802.11n. Through all of the wild-eyed claims of performance increases and radical shifts in the world of enterprise networking, I thought I would offer up some humble (or maybe a bit beyond humble) perspectives on the state of enterprise Wi-Fi, the emerging 802.11n standard, and what customers really need to consider on this front:

1. First and foremost -- 802.11n certainly represents an intruiging step forward for the wireless industry. It promises to deliver a significant step up in performance, which has been well covered in press. What is not as well covered, but perhaps even more compelling for customers today, is the substantial improvement in overall reliability that 802.11n will bring to networks. No customer is expecting an immediate "0 to 100%" shift to 802.11n users and clients. With the backwards compatibility of .11n, for existing .11b/g users, the compelling 'why to migrate' now case will often lie with reliability for all Wi-Fi clients across the business.

2. Make no mistake -- moving to 802.11n is both a wireless AND wired decision. Given the theoretical available bandwidth in a dual-radio .11n access point of 600 mbps (300 mbps per radio -- expect closer to 130 Mbps, no matter what vendor release you read) there is an obvious need to provision a 1 Gbps Ethernet port to backhaul the AP traffic. Another critical deployment consideration is how to power these new access points. Any competitive 802.11n AP requires more power than is provided via a standard 802.3af power-over-Ethernet port. Workaround options include provisioning two 802.3af ports (not high on any IT department lists of desireable activities -- run more wire to the AP...) or my personal favorite, utilize one 802.3af port, and run a dual radio AP in "pico cell" mode (code for running at half-capacity and performance). External power injectors are always an option, as are the ole AC power outlets, but the latter could put a crimp in any deployment.

3. Here is where having a nice Ethernet switching franchise comes in handy if you are a vendor in this space (and where claims of 802.11n representing a major vendor market share shift fall way short). Cisco is announcing today its new Enterprise WLAN 802.11n offering today, and it is about more than the access point (which is quite a nice, modular platform). It is equally about delivering a true wired and wireless solution that actually considers how a customer could actually deploy with as much simplicity, and as little network architecture disruption as possible. Cisco will be delivering an auto-negotiating, single port extended power capability across switches in its Catalyst 3750, 4500 and 6500 families. This means, with a large number of customers out there, customers will be able deploy 802.11n and utilize their existing wiring closet switches to deliver the extra power required to take advantage of those wireless performance and reliability kickers that 802.11n offers. Delivering the easiest power solution for 802.11n may not make for the best headlines, but it is one of those fundamentals that must be addressed.

4. So that brings me to my last thought -- I've been reading some recent comments by a Enteprise WLAN vendor wondering aloud to the press why any vendor would ship a 802.11n draft 2 solution today. The reasoning centered around two key points: the final standard has not been ratified, and Cisco hasn't announced a product. Well -- to comment on the Cisco point, we have announced a product, and it has everything to do with customer demand and supply chain reality. Customers are starting to ask for 802.11n. Chipset manufacturers like Intel and others are shipping 802.11n silicon. PC manufacturers are releasing 802.11n-capable product. The market seems to have spoken, and to follow the lessons learned from earlier Wi-Fi days -- clients will drive the infrastructure. Cisco chose a deliberate approach to this space -- get Wi-Fi Alliance (and it turns out, the only to date..) certification, participate in the test bed, and then bring 802.11n product to market. On the final standard ratification point -- I'd offer that given the supply chain momentum and rising customer interest in 802.11n draft 2, it becomes hard to argue why any serious vendor wouldn't have an offering. While there is no 100% guarantee, it is truly hard to imagine any upgrade beyond software to bring an 802.11n draft 2 product into compliance with the final standard. So to the vendor that just last week asked why .. I'd respond .. why not?

So to be sure, the emergence of 802.11n for businesses will be met by a distinct, early adopter market over the next year. Such customers certainly deserve both an easy, deployable solution, and also information to set expectations on the performance, reliability and reach of this new technology. Please visit http://www.cisco.com/en/US/netsol/ns767/networking_solutions_package.html on an ongoing basis for more information on 802.11n, including soon to be released information on benchmarking testing between Cisco and Intel. Enough of pre-announcement press releases -- let's dig into the reality of 802.11n. What are your expectations for performance, reliability, and reach? Any plans to deploy soon? Next year? Three? Never? Please share!

Posted by Ben Gibson at 10:47 PM Permalink | Comments (1) | TrackBacks (0)

"Too Long A Sacrifice": Thoughts on Muni Wi-Fi

Readers Note: this is second blog relating to thoughts on my dual-mode device.

"Hearts with one purpose alone
Through summer and winter seem
Enchanted to a stone
To trouble the living stream."
- W.B. Yeats, "Easter 1916"

I am in a literary mood this labor day and I was thinking about the seminal poem on the Irish revolution, whereby W.B. Yeats noted that “too long a sacrifice/can make a stone of the heart.” To this, the Muni Wi-Fi cottage industry, of which we at Cisco are, to be fair, members, has wrestled with business models and performance claims. With the delay of the much heralded San Francisco network, and its attendant issues all around to service providers, digital inclusion partners, and, yes, equipment vendors, it is clear we have now ended Muni Wi-Fi’s “summer of discontent.”

Yet I do not think we are at the unremarkable end of city-wide Wi-Fi networks. Indeed, now that we have burned off the ephemeral and seemingly endless dialogues about “advertising-led” networks (can you imagine, we spend our lives DVRing all of television so we can be assaulted by more ads when we are out and about???), we can get back to the real goals and financial models of these networks.

Yes, they are networks. They have network economics. Lots of people have to use them for real reasons for them to make sense. Increasingly, in the Web 2.0/collaborative world, the reason might have less to do with web-surfing then with being able to create mobile social networks. My top use of my dual-mode include new messaging apps that are rapidly replacing email in my communications pantheon.

Thus the avalanche of dual-mode devices, including my trusty Nokia e61i, starts to kick in. These are exactly the kinds of devices, including the lovely Apple iPhone that can take advantage of these networks. Connecting ME/YOU to specific kinds of information, adding a real-time nature to social/business collaboration might be a (cough) killer app. Increasingly I use my dual mode for downloading forms of video (training, entertainment, etc.) It is an ideal medium for 2-3 minute clips.

So speed does count. I am now just starting to get reports of people using the iPhone on our WLAN mesh networks across the country. The superior download speeds of these networks compared to the Edge cellular networks make for a more compelling surfing/ downloading experience. And as HPDSA/3G becomes more pervasive, the bar becomes notched up just another level. Guess what? 802.11n comes into Muni networks, next. What a great thing for users!

To paraphrase Twain: rumors on demise of Muni Wi-Fi networks are much exaggerated.

Posted by Alan Cohen at 09:39 AM Permalink | Comments (0) | TrackBacks (0)