Cisco Blogs


Cisco Blog > Enterprise Networks

Scaling the Internet with 6500 Switches Ternary Content Addressable Memory(TCAM) Customization

The Internet routing table size has continued to grow steadily. In 2008 we reached 256K routes and now the table has exceed 512K Routes. This is of significance for customers running some of the older PFC3 based Supervisor 720 engines on the 6500 and 7600 switches.

On the Catalyst 6500 and 7600 Series platforms, all of the routing information is stored in special high-speed memory called TCAM. Read More »

Tags: , , ,

IPv4 depletion: Threat? Danger? Crisis? Turning IPv6 Up and IPv4 Down

I was interviewed recently for an article in Tweakers. It’s a good article, but I think a shade of meaning was lost in translation between Dutch and English. Hence, I’d like to restate the article in my own words.
The nuance of meaning revolves around the words “danger”, “threat”, and “crisis”. Joost opened the interview asking me whether I thought that IPv4 depletion presented a threat, and whether the Internet was in danger. I replied that there was a crisis, but not a threat.

Read More »

Tags: , ,

LISPmob, a new open source project for network mobility

What if your mobile device allowed you the freedom to seamlessly roam across any network in the world, regardless of location or operator and with all the attributes you would expect, security or privacy…  With LISPmob, we may have gotten a giant step closer as we open sourced a network stack for network mobility on Linux platforms, an implementation of basic LISP mobile node functionalities.

This is the Locator Identifier Separation Protocol, which supports the separation of the IPv4 and IPv6 address space following a network-based map-and-encapsulate scheme based on an IETF open standard.

We hope this will be a project and a community many will find not just interesting and vibrant, but necessary and fun to engage, collaborate and contribute.

How will this help your plans to deal with all these amazing possibilities of mobile access to an ever-growing Internet?

Tags: , , , , , , , , ,

Happy Eyeballs for World IPv6 Day

Imagine how “happy” your eyeballs would become when you realize that your Internet connection failover time was drastically reduced from a full minute to less than half a second, Dan Wing and Andrew Yourtchenko of Cisco developed a methodology to do just that.

The Internet is changing. Network operators and content providers are beginning the widespread global deployment of IPv6, while keeping IPv4 up and running until IPv6 is ready to take over. Dan and Andrew have contributed to the cause of easing the adoption of IPv6 by documenting a methodology that will enable client applications to react more responsively in dual-stack failure scenarios by aggressively rectifying intermittent access issues and therefore preserve the end user experience for dual-stack IPv4 and IPv6 devices. This solution is documented in their IETF draft, cleverly named Happy Eyeballs. It is designed to keep the eyeballs of a computer end user “happy” in the face of problems that may exist when a host is attempting to establish IPv4 or IPv6 connectivity. The IETF draft document describes how client applications should behave when establishing IPv6 and IPv4 connectivity simultaneously, preferring IPv6 if the connectivity is successful, and disconnecting any remaining redundant (IPv4 / TCP) connections. By failing over quickly from IPv6 to IPv4, or from IPv4 to IPv6, the user is not affected by problems that occur in only one of the two IP versions in a dual-stack deployment. This can greatly reduce the connection times in problematic situations -- from minutes to milliseconds, compared to the typical behavior in many implementations today.

In anticipation of World Ipv6 Day, Google Chrome has adopted a similar approach to what Dan and Andrew have documented, under the somewhat less light-hearted name “IPv4-Fallback”. This modification promises to ease potential trouble spots on World IPv6 Day, as well as future browser interactions with dual-stack network configurations. Google’s Internet browser, Chrome 11, uses a “hybrid” variation of Happy Eyeballs that is responsible for establishing, monitoring, and management of simultaneous parallel IP connections. This software enhancement produces significant results by reducing the fallback latency of a problematic IPv6 connection from between 20 and 75 seconds as is often seen today, to as little as 300 milliseconds.

Read More »

Tags: , , , , ,

For IPv4 the Sunset Begins. For IPv6 the Day Is Just Getting Started

That was quick! I mentioned earlier in the week that, in any day, the IANA would hand out the last IPv4 address. Today it happened. And coinciding with the X-day, our panel discussed the true impact of the IPv4 address run-out. To mitigate it, Cisco’s Carrier-Grade IPv6 (CGv6) solution is designed to help enable a smooth transition.

Cisco Carrier Grade IPv6 (CGv6) Solution

One interesting observation I’ve seen is how something as obtuse and techie as IPv6  has generated so much interest in the main stream press - such as this article at the Wall Street Journal, Web Running Out of Addresses.  Even my mother asked me about it on the phone last night “will the internets shut down?” No way mom…we’ve got that covered. The Internet will be Preserved, Prepared, and then Prosper!

Read More »

Tags: , , , , ,