Posts Tagged 'Switches'

July 26, 2012

Global IP Addresses - What Are They and How Do They Work?

SoftLayer recently released "Global IPs" to a good amount of internal fanfare, and I thought I'd share a little about it with the blog audience in case customers have questions about what Global IPs are and how they work. Simply put, Global IP addresses can be provisioned in any data center on the SoftLayer network and moved to another facility if necessary. You can point it to a server in Dallas, and if you need to perform maintenance on the server in Dallas, you can move the IP address to a server in Amsterdam to seamlessly (and almost immediately) transition your traffic. If you spin up and turn down workloads on cloud computing instances, you have the ability to maintain and a specific IP address when you completely turn down an environment, and you can quickly reprovision the IP on a new instance when you spin up the next workload.

How Do Global IPs Work?

The basics of how the Internet works are simple: Packets are sent between you and a server somewhere based on the location of the content you've requested. That location is pinpointed by an IP address that is assigned to a specific server or cloud. Often for various reasons, blocks of IP addresses are provisioned in one region or location, so Global IPs are a bit of a departure from the norm.

When you're sending/receiving packets, you might thing the packets "know" the exact physical destination as soon as they're directed to an IP address, but in practice, they don't have to ... The packets are forwarded along a path of devices with a general idea of where the exact location will be, but the primary concern of each device is to get the all packets to the next hop in the network path as quickly as possible by using default routes and routing tables. As an example, let's follow a packet as it comes from an external webserver and detail how it gets back to your machine:

  1. The external webserver sends the packet to a local switch.
  2. The switch passes it to a router.
  3. The packet traverses a number of network hops (other routers) and enters the Softlayer network at one of the backbone routers (BBR).
  4. The BBR looks at the IP destination and compares it to a table shared and updated with the other routers on SoftLayer's network, and it locates the subnet the IP belongs to.
  5. The BBR determines behind which distribution aggregate router (DAR) the IP is located, then it to the closest BBR to that DAR.
  6. The DAR gets the packet, looks at its own tables, and finds the front-end customer router (FCR) that the subnet lives on, and sends it there.
  7. The FCR routes the packet to the front-end customer switch (FCS) that has that IP mapped to the proper MAC address.
  8. The switch then delivers the packet through the proper switchport.
  9. Your server gets the packet from the FCS, and the kernel goes, "Oh yes, that IP on the public port, I'll accept this now."

All of those steps happen in an instant, and for you to be reading this blog, the packets carrying this content would have followed a similar pattern to the browser on your computer.

The process is slightly different when it comes to Global IP addresses. When a packet is destined for a Global IP, as soon as it gets onto the SoftLayer network (step 4 above), the routing process changes.

We allocate subnets of IP addresses specifically to the Global IP address pool, and we tell all the BBRs that these IPs are special. When you order a global IP, we peel off one of those IPs and add a static route to your chosen server's IP address, and then tell all the BBRs that route. Rather than the server's IP being an endpoint, the network is expecting your server to act as a router, and do something with the packet when it is received. I know that could sound a little confusing since we aren't really using the server as a router, so let's follow a packet to your Global IP (following the first three steps from above):

  1. The BBR notes that this IP belongs to one of the special Global IP address subnets, and matches the destination IP with the static route to the destination server you chose when you provisioned the Global IP.
  2. The BBR forwards the packet to the DAR, which then finds the FCR, then hands it off to the switch.
  3. The switch hands the packet to your server, and your server accepts it on the public interface like a regular secondary IP.
  4. Your server then essentially "routes" the packet to an IP address on itself.

Because the Global IP address can be moved to different servers in different locations, whenever you change the destination IP, the static route is updated in our routing table quickly. Because the change is happening exclusively on SoftLayer's infrastructure, you don't have to wait on other providers propagate the change. Think of updating your site's domain to a new IP address via DNS as an example: Even after you update your authoritative DNS servers, you have to wait for your users' DNS servers to recognize and update the new IP address. With Global IPs, the IP address would remain the same, and all users will follow the new path as soon as the routers update.

This initial release of Global IP addresses is just the tip of the iceberg when it comes to functionality. The product management and network engineering teams are getting customer feedback and creating roadmaps for the future of the product, so we'd love to hear your feedback and questions. If you want a little more in-depth information about installation and provisioning, check out the Global IP Addresses page on KnowledgeLayer.

-Jason

October 27, 2011

SoftLayer Features and Benefits - Data Centers

When we last talked, I broke down the differences between features and benefits. To recap: a feature is something prominent about a person, place or thing, while a benefit is a feature that is useful to you. In that blog, I discussed our customer portal and the automation within, so with this next installment, let's move into my favorite place: the data center ... Our pride and joy!

If you have not had a chance to visit a SoftLayer data center, you're missing out. The number one response I get when I begin a tour through any of our facilities is, "I have been through several data centers before, and they're pretty boring," or my favorite, "We don't have to go in, they all look the same." Then they get a glimpse at the SoftLayer facility through the window in our lobby:

Data Center Window

What makes a SoftLayer DC so different and unique?

We deploy data centers in a pod concept. A pod, or server room, is a designed to be an identical installation of balanced power, cooling and redundant best-in-class equipment in under 10,000 square feet. It will support just about 5,000 dedicated servers, and each pod is built to the same specifications as every other pod. We use the same hardware vendor for servers, the majority of our internal network is powered by Cisco gear and edge equipment is now powered by Juniper. Even the paint on the walls matches up from pod to pod, city to city and now country to country. That's standardization!

That all sounds great, but what does that mean for you? How do all these things benefit you as the end user?

First of all, setting standards improves our efficiency in support and operations. We can pluck any of our technicians in DAL05 and drop him into SJC01, and he'll feel right at home despite the outside world looking a bit different. No facility quirks, no learning curve. In fact, the Go Live Crews in Singapore and Amsterdam are all experienced SoftLayer technicians from our US facilities, so they help us make sure all of the details are exactly alike.

Beyond the support aspect, having data centers in multiple cities around the world is a benefit within itself: You have the option to host your solution as close or as far away from you as you wish. Taking that a step further, disaster recovery becomes much easier with our unique network-within-a-network topology.

The third biggest benefit customers get from SoftLayer's data centers is the quality of the server chassis. Because we standardize our SuperMicro chassis in every facility, we're able to troubleshoot and resolve issues faster when a customer contacts us. Let's say the mainboard is having a problem, and your Linux server is in kernel panic. Instead of taking time to try and fix the part, I can hot-swap all the drives into an identical chassis and use the portal to automatically move all of your IP addresses and network configurations to a new location in the DC. The server boots right up and is back in service with minimal downtime.

Try to do that with "similar" hardware (not "identical"), and see where that gets you.

The last obvious customer benefit we'll talk about here is the data center's internal network performance. Powered by Cisco internal switches and Juniper routers on the edge, we can provide unmatched bandwidth capacity to our data centers as well as low latency links between servers. In one rack on the data center floor, you can see 80Gbps of bandwidth. Our automated, high-speed network allows us to provision a server anywhere in a pod and an additional server anywhere else in the same pod, and they will perform as if they are sitting right next to each other. That means you don't need to reserve space in the same rack for a server that you think you'll need in the future, so when your business grows, your infrastructure can grow seamlessly with you.

In the last installment of this little "SoftLayer Features and Benefits" series, we'll talk about the global network and learn why no one in the industry can match it.

-Harold

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