Do you understand how much bandwidth 1 Gbps is? That's the question I often find myself asking users.
At our largest sites we have deployed Gigabit to the desktop - not because users need it, but because the price difference between 10/100/1000 and 10/100 cards in Cisco 6500s is small. Plus, there are better features in the 10/100/1000 blades than in the older 10/100 cards. So, might as well get the Gig blades.
Now, that doesn't mean users always get Gigabit. Some older PCs only support 100 Mbps. However, most of our PCs and laptops have Gigabit NICs and users have become accustomed to seeing "Connected 1.0 Gbps" when their PC boots up. And once users have Gigabit, they just assume they need it.
Last year we refreshed the network switches at our small sales offices. To save money we purchased Cisco 3750 10/100 switches. In the 3750 line there is a significant price difference between 10/100/1000 and just 10/100. Most of these field sites have sales people and connect to the Data Center over two 3 Mbps WAN circuits. Three Mbps! But the outcry when these users lost their Gig ports was intense. "How can I work with only 100 Mbps?". "There's no way I can get my testing done without Gig". It was unreal.
Then it happened again over the last few weeks. As I mentioned above, our largest sites have been outfitted with 10/100/1000 for a while and users have come to expect their PC connected at 1 Gbps. Then, over the last few weeks, we started deploying Cisco IP Phones with only 10/100 ports. User PCs connect to the phone which connects to the network. Here comes the outrage again. "My team cannot support this change. Deploy new ports to our cubes so we can have Gig again". "This is going to impact our ability to support customers, my testing will slow down". "IT just doesn't understand our needs."
After several minutes of trying to explain to no avail to users they don't need 1 Gbps since their network traffic patterns are not intense or sustained enough; or trying to explain there are no PCs that could even push 1 Gbps; or explaining the study we did a few months ago that showed the highest user port averaging around 40 Mbps I find my self asking them "Do you understand how much bandwidth 1 Gbps is? You don't need it. 100 Mbps is fine! In fact, 10 Mbps would probably be ok."
Yes, there are definitely servers, databases, and network storage in a Data Center than can fill and benefit from 1 Gbps ports, but not users. Any traffic over WAN links is going to be limited by lower WAN bandwidth and effect delay has on TCP. So, unless you're sitting on the same LAN as the DC with a home-built, water-cooled super-PC running your own compiled version of Linux......YOU DON'T NEED A GIG PORT!
PS - Gartner agrees with me.
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Michael Morris is a communications engineering manager at a $3-billion high-tech company. His background is in enterprise WANs working with telcos and developing large-scale routing designs. He has worked on networks at government and corporate organizations, including networks at two Fortune 10 companies. In his current role, he leads a team of 10 engineers responsible for large-scale IT networking projects and architectural standards for data networks, storage area networks, IP telephony, contact centers, and security. Michael is CCIE #11733 and recently became one of the first three Cisco Certified Design Experts (CCDE) ever (#20080002). He has 11 years experience in networking and communications, including four years as a paratrooper in the U.S. Army. He has a bachelor's degree in MIS from the University at Buffalo and is working on his MBA from NC State University. In 2008, he was awarded the Network Professional Association (NPA) Professional Excellence and Innovation Award for his work on network architecture, templates and enterprise MPLS design.
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There will come a time when
There will come a time when we will need GIG speed over the wired to keep up with the ever increasing wireless demands. Enterprise 802.11n access points will support speeds exceeding 200Mbps. Even then we will be under the mercy of the WAN (ingress). You are right Airborne, there are always bottlenecks in networks.
Wireless networks are by
Wireless networks are by definition shared "media"compared to the switched networks where all connections are point to point.
When numerous users are connected to the same access point the bandwith decresse by the same factor.
for backup
Do I need gigabit when we do our nightly images of our server over the LAN? I know its only 30-40 gigabytes but still....
GLF
RE: for backup
Yes, most likely GIG will be very useful for nightly backups. In that case you (should) have a powerful server that has the CPU strength to push near a GIG a traffic and you have sustained traffic flow (the backup itself). This is completely opposite from desktop users.
For your backups, just keep an eye on latency, TCP window size, and protcol used. Even with 1 msec delay and a full TCP window (65,536), the max transfer rate is about 524 Mbps, which is 1/2 a Gig.
http://www.wand.net.nz/~perry/max_download.php?bits_per_second=1000000000&ack_size=40&no_delayed_acks=2&mss=1460&rtt=1&wsize=65536&ploss=0
If you can split the backup into two TCP sessions you should get full link utilization. Or, some backup software can alter the max-TCP window to allow a better transfer rate. For example, Network Appliance's SNAP backup protocol can alter the max TCP window to 2,000,000, which results in much greater bandwidth utilization from a single TCP session:
http://www.wand.net.nz/~perry/max_download.php?bits_per_second=1000000000&ack_size=40&no_delayed_acks=2&mss=1460&rtt=1&wsize=2000000&ploss=0
Mike