Hi Tom, Comments inline below:
> The problem is that most Internet and subscriber traffic is using a 1500MTU or smaller frame. So in theory, its would be just as efficient and fast to bond two 100 mbps fiber connections than it would to buy 1- 1GB fiber connection. No, it wouldn't be. > So the question is.... How do we most efficiently use 1GB fiber to get the advantage of the full 1GB of capacity? Simple: Install hardware that can pass 1 Gbps. > Do we need to use some sort of packet agreegation/stuffing technology? No. > Is GB etherner pointless for Internet transit backbones? No. > Is GB just good for high capacity Transports, recognizing that routers will likely split traffic to different smaller bandwidth peers? No. > Is there a special router or router feature used to solve this problem? No. No special features or hardware are necessary. > Is that method available to Linux? Yes, though Linux is designed for SERVER performance, so a stock kernel will likely also present some other bottlenecks. > The reason I ask is several fold. In a network design where all traffic flows to a single source (for example many 100mbps baclhauls to remote areas to 1 central data center), it would be beneficial because the cost of 1 big 1GB pipe could be shared to deliver capacity to everything, better apt to handle peak traffic and get higher oversubscription rates. However, if teh GB INternet pipe can not be efficiently used, this method would be severally flawed. It might be better to have multipel 100mvps transit connections spread out across one's network, so there was a shorter path to transit, and the network's bandwdith spread out amungst multiple 100mbps transit connection, for better over all throughput. In other words, in a 10 city network, 1- 100mbps pipe in each of teh 10 cities would allow a full combined 1 gbps of Internet transit, where as agregating 100mbps from each city to one central source where their was a single 1GB transit, would result in only a 200mbps throughput, assuming traffic was delivered to it as a 1500 MTU. > Any feedback? > Take note that my comment that a 1500MTU frame 1 Gbps Ethernet card could only pass 200kbps was based on some lab tests. The solution is simply a hardware upgrade for starters. A 32-bit/33 MHz bus will top out around 200 Mbps. If you look for a bus with higher speed slots, you can triple your throughput without adjusting ANYTHING in your Linux kernel. If you want wirespeed GigE performance with multiple packet streams at a more reasonable packet size (remember that 1500 byte packets aren't realistic), you'll need to make some adjustments to the kernel. > With the 1500MTU frame acheiving only 200kbps, our routers CPU utilization was less than 20%, so it was not a saturated router. Actually, it is. Utilities top and vmstat don't necessarily reflect all of the CPU utilization, and can't account for PCI bus contention/overhead. > The second we changed MTU to 9600, we got over 800 mbps, and CPU utilization was still very low, forget exact number but under 40%. Well, sure...you've just taken your packet rate down significantly. You still have bus overhead and the limitations of a 32/33 bus (1 Gbps burst capacity). Regards, Jeff Tom DeReggi RapidDSL & Wireless, Inc IntAirNet- Fixed Wireless Broadband -- WISPA Wireless List: [email protected] Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/ -- WISPA Wireless List: [email protected] Subscribe/Unsubscribe: http://lists.wispa.org/mailman/listinfo/wireless Archives: http://lists.wispa.org/pipermail/wireless/
