What is LISP DDT?

Some background on LISP

LISP (Locator/Identifier Separation Protocol) is a smart and novel method to create overlay networks with features such as multi-homing, mobility and VPN-segregation. These feats are possible because LISP makes a distinction between the 'who' and the 'where'.
"The separation of location and identity is a step which has recently been identified by the IRTF as a critically necessary evolutionary architectural step for the Internet."
- N. Chiappa in draft-chiappa-lisp-introduction-00 
An example would be that my IPv6 prefix 2001:67c:208c:10::/64 (the 'who') currently is located behind the following WAN IP addresses: 62.194.155.106, 217.8.107.2 and 2001:67C:21B4:1::2 (the 'where'). In this example my prefix is multi-homed behind 3 connections, and I'm doing IPv6 over IPv4 next to IPv6 over IPv6. This is possible because this single IPv6 prefix can have multiple Routing Locators (the 'where') and LISP is address-family agnostic.

Mapping systems for location information

As you can imagine, the key to protocols like LISP is locating who is where in a fast and efficient way.

To create more context: with the Border Gateway Protocol (BGP) all participating nodes (routers) have all information about everybody in memory. When an organisation Continue reading

KIClet: Microphone troubles with Lenovo W520

I came across this the other day and wanted to share. For some reason, Windows by default decided to enable the “audio enhancements” feature on my new Lenovo Thinkpad w520. This caused my microphone to essentially be unusable - I was in several webex meetings and each time everyone said I was completely garbled and not even close to being able to understand me. After a little poking around, I found this:

KIClet: Microphone troubles with Lenovo W520

I came across this the other day and wanted to share. For some reason, Windows by default decided to enable the “audio enhancements” feature on my new Lenovo Thinkpad w520. This caused my microphone to essentially be unusable - I was in several webex meetings and each time everyone said I was completely garbled and not even close to being able to understand me. After a little poking around, I found this:

Get-Console Review on the iPad

I have used my iPad to console onto Cisco routers and switches for about 2 years now. I started using the Flex-Serial cable on my jailbroken iPad and iPhone, with the iSSH app and a ported version of Minicom (earlier blog post).  Amidst some minor bugs and irritations this worked well and was considerably more […]

The Internet is Broken, and How to Fix It

Some puzzle pieces of a picture puzzle.

Many real time applications such as VOIP, gaming,  teleconferencing, and performing music together, require low latency. These are increasingly unusable in today’s internet, and not because there is insufficient bandwidth, but that we’ve failed to look at the Internet as a end to end system. The edge of the Internet now often runs congested. When it does, bufferbloat causes performance to fall off a cliff.

Where once a home user’s Internet connection consisted of a single computer, it now consists of a dozen or more devices – smart phones, TV’s, Apple TV’s/Roku devices, tablet devices, home security equipment, and one or more computer per household member. More Internet connected devices are arriving every year, which often perform background activities without user’s intervention, inducing transients on the network. These devices need to effectively share the edge connection, in order to make each user happy. All can induce congestion and bufferbloat that baffle most Internet users.

The CoDel (“coddle”) AQM algorithm provides the “missing link” necessary for good TCP behavior and solving bufferbloat. But CoDel by itself is insufficient to solve provide reliable, predictable low latency performance in today’s Internet.

Bottlenecks are most common at the “edge” of the Internet and there you must Continue reading

CCIE Security

I have just successfully passed the CCIE Security written exam at Cisco Live 2012. The exam was no cake walk and was very challenging. Although I studied all the material from the CCNP security track and read the Network Security Technologies and Solutions (CCIE Professional Development Series) book I did not take any of the CCNP Security exams. I took a little different approach to this CCIE then I took in the R&S track. I will be starting to do the practice labs and will go back to theory throughout the process to do each of the CCNP Security exams. I am hoping that this ensures that I perform the practice labs without fail and continue to cement the theory throughout the process.


Thoughts?

Just for fun: I love Junos in OP Script

A simple op script, just for fun. Next blog post will be more serious :) FOR TERMINAL : 24 Rows / 80 Columns / font: Courrier New 10 The video can see here : The 'op' script is called lovejunos.slax. It has been tested with release 11.4. You can simply...

Just for fun: I love Junos in OP Script

A simple op script, just for fun. Next blog post will be more serious :) FOR TERMINAL : 24 Rows / 80 Columns / font: Courrier New 10 The video can see here : The 'op' script is called lovejunos.slax. It has been tested with release 11.4. You can simply...

Just for fun: I love Junos in OP Script

A simple op script, just for fun. Next blog post will be more serious :) FOR TERMINAL : 24 Rows / 80 Columns / font: Courrier New 10 The video can see here : The 'op' script is called lovejunos.slax. It has been tested with release 11.4. You can simply...

Cisco Live 2012 San Diego

That was it! My work life has an absolute peak every year and that’s when I’m again fortunate enough to visit Cisco Live in the US. This year it was held in San Diego, California.
I flew in on Saturday with 2 colleagues on LA and drove to San Diego after a quick tour around Sunset Boulevard ;)

We stayed at the Manchester Grand Hyatt, which is a hotel I can truly recommend when visiting San Diego. Services were good and staff was helpful!

My focus this year was to combine both Datacenter and Service Provider sessions as those are the fields I’m active in. I found that the SP related sessions had a quite smaller crowd attending them. I guess this is related as the SP customers are considered important customers and get a lot more attention from Cisco people, so they already know what to expect in terms of roadmap and technologies. Still I had quite some very good sessions where I learnt about the features (and limitations) about some cool new things :-)

Sunday
On Sunday it’s a special day as you need to purchase additional sessions called Techtorials. This was the first year I took a Continue reading

CCIE Datacenter techtorial notes

The CCIE Datacenter techtorial was a very good session giving a good overview about the contents of the exam. I will not focus on the technologies in this article, but only on the specifics that I wrote down during the session. This means you will only find details about the exam and not about the technologies.
There are enough resources to find details about the technologies, but you are reading this article if you want to know what to find when you step into the testing center or the lab.

The session was presented by 3 guys, I would specifically mention Walid Issa who is the product manager for this particular CCIE track. Walid is a very nice guy and if you want to know something about the lab, ask him!

Written
Over 200 took the written beta already. it’s expected that a lot more people will take the DC written beta during Cisco live San Diego.

The Written is an overview of technologies with a medium to hard level. As all other written exams for CCIE the focus is on theory and not on configuration. When you know the technologies you should be able to pass.

Lab

Sample topology Continue reading

Packets of Interest 2012-06-12 — OSPF Refresher

I was recently brushing up and refreshing my OSPF knowledge and I discovered some great resources that I wanted to document for my future use and also share with others. I found these resources great for explaining/detailing area types, packet types, and neighbor states. This first document hosted at packetlife.net is one of the best explanations of packet types I've ever seen due to the visual aids that the author, Jeremy Stretch, incorporated.

How would you like to do IP Multicast without PIM or RP’s? Seriously, let’s use Shortest Path Bridging and make it easy!

 

Why do we need to do this? What’s wrong with today’s network?

Anyone who has deployed or managed a large PIM multicast environment will relate to the response to this question. PIM works on the assumption of an overlay protocol model. PIM stands for Protocol Independent Multicast, which means that it can utilize any IP routing table to establish a reverse path forwarding tree. These routes can be created with any independent unicast routing protocol such as RIP or OSPF, or even be static routes or combinations thereof. In essence, there is an overlay of the different protocols to establish a pseudo-state within the network for the forwarding of multicast data. As any network engineer who has worked with large PIM deployments will attest, they are sensitive beasts that do not lend themselves well to topology changes or expansions of the network delivery system. The key word in all of this is the term ‘state’. If it is lost, then the tree truncates and the distribution service for that length of the tree is effectively lost. Consequently, changes need to be done carefully and be well tested and planned. And this is all due to the fact that the Continue reading

Today is World IPv6 Launch Day!

After the success of last year’s World IPv6 Day, where success was measured with little to no problems reported, World IPv6 Launch Day has arrived! For a while major players like Google and Facebook had been white-listing their AAAA records to specific ISP recursive nameservers. This meant you had to query one of those in order to see IPv6 entries for their websites. Now that white-listing has been removed and all properly operating recursive nameservers will now serve up these records. They aren’t the only companies participating of course! Take a look at this list to see whom else signed up to promote their enabling of IPv6. Want some stats, take a look at the following:

But what does this mean to the non-techies out there? It is meant to be a passive change. You shouldn’t notice much in the way of interruptions. Perhaps your ISP will have a shorter route to a destination over IPv6, and you might get what you are trying to access a tiny bit quicker. If you like video/chat applications, this will soon mean that you’ll be Continue reading

The Best MPLS Lecture on the Net

The title says it all. Professor Karandikar gives two amazing lectures on MPLS and MPLS-TE that most engineers should hope to know cold. I watch it probably once every few months. Not saying much for my memory these days. It is an amazing amount of material delivered very precisely. Great stuff! I added some figures to […]

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Ethernet Switch Fabric Cards

I was working with a buddy today about switch fabric cards in the nexus 7000 and not doing a very good job at explaining it, so I figured I would draw some pictures. The conversation was around how adding more fabric cards increases the bandwidth. I think some, myself included growing up on Catalyst 6500’s […]

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