TED.Com – Amazing Lectures
Posted by Greg in Uncategorized on March 10th, 2010
I know this isn’t really the usual technical article that I post, but this site is pretty, well, amazing. I’ve watched some amazing dancers, heard an Indian artist tell his story and even listened to an autistic woman speak about how her mind works like google images. All of it is free and most of it is less than 30 minutes.
TED.Com
Thanks to Normands for buzzing a link to a talk which ultimately got me browsing this site.
Gathering Information With Cisco IP SLA and Cacti
Posted by Greg in Cacti, Cisco, Networking on March 8th, 2010

Modern enterprise networks often span provider networks, be it IPSec tunnels through the internet or a leased MPLS connection. If one is experiencing problems, how can you definitively diagnose these issues? There are few tools cheaper and more effective than using Cisco’s IP SLA ( IP Service Level Agreement), formerly SAA and RTTMON.
In a nutshell IP SLA is a service that runs between two Cisco routers. This service generates statistics on:
For my purposes, I use Jitter most frequently. A common scenario would be to test line quality between IPSec connected locations.
So what will we need?
For the Cacti install, I always use CactiEZ.
For my Cisco routers I usually use whatever I can find, generally the cheaper the better. I’ve got some 1700s from Ebay for $8 each. I just recently grabbed some 836s from Cables and kits for $4.80 each!
Here’s our diagram.
So this setup shows two sites that connect with an IPSec connection. Our users have been seeing what they think is packet loss causing tunnel problems. The ISPs at both locations claim they are having no issues. You are currently graphing the internet bandwidth on both WAN interfaces via your cacti box and you see that you aren’t maxing out your bandwidth. Sooo, it looks like you are having packet loss within one of your ISPs, but how can you prove it?
What we do is put an IPSLA probe in both locations and one at a neutral location. We configure SLA server to run on each router, which accepts SLA probe connections. We then configure all sites to probe each other, and add it to cacti.
Soooo, if we get packet loss from a single site to all other locations, then we know which ISP to call. On top of that, we will have graphical proof that we can send to the ISP to help prove our point
IPSLA1
Setup the jitter probe and have it hit SLA2 every 5 minutes. The frequency is set in seconds.
1 2 3 4 | ip sla monitor 1 type jitter dest-ipaddr 192.168.2.2 dest-port 10000 frequency 300 ip sla monitor schedule 1 life forever start-time now |
IPSLA2
Setup IPSLA2 to respond to the queries.
1 | ip sla responder |
Add your graph in cacti and awaaaaaay you go.
Random Cable Cut In Datacenter
This is one of the least funny videos I’ve seen in a while (thanks Brian)…This makes me stop and think “What would I do in this situation?” Punch the guy in the face as soon as I see scisors springs to mind…hehehe
MUM PDFs
Here’s the new 250GS switch, which is rumored to be less than $100:
Indeed it looks like the 750/G, but it is different under the hood. This guy doesn’t route, it will only switch.
This guy also runs the SwOS, switch OS. This guy is configured via a fairly simple web interface.
I stole those details from this pdf. There are also screenshots with the PDF.
RB1100 Details…A Few Anyway
As you know it is 13 port gig that shares the same processor as the RB800. It is supposed to have equivalent processing power as the RB1000, though. This guy has the two 5 port switching asics built in, so the switching backplane is split…which sucks. There are no SFP ports…I would have traded 5 gig ports and switching ASIC for a couple of SFP ports.
This guy can also be powered via a PoE port.
They also put venting in the front. I believe this guy is fanless, so it will use convection to displace the heat, which I like.
Looks like this guy will be coming in at around $499, which means Baltic will probably have it for like $460, but who knows
I would rather have seen them charge $1000 and give us some real beef (multi cores, SFP ports, line rate on all gig ports).
I also read that the new switch introduced is only 5 ports. No news on the possible price.
What would you guys liked to have seen?
Polish MUM Live – 3/1/2010
For all of you lucky enough to make it to the Polish MUM, you can ignore this. For the rest of us, Mikrotik is going to be streaming the event live via ustream. I’m CST, so Poland is 7 hours ahead, so I most likely won’t be able to catch too much, but I’m going to try anyway. To all of you there, I’d be interested to hear your opinions.
New Equipment Announcement Polish MUM (matka)
- RB1100 13-port gigabit rackmount router
Looks like they are announcing the successor to the RB1K series. 13 port router…I hope some of those ports are SFP ports! I assume the form factor will still be 1U, but who can really say.
- RB250G smart gigabit switch with new SwOS (SwitchOS)
They’ve finally done it! They are releasing a switch, with SwOS no less. I wonder if we will still be winboxing into these guys…I’m going to assume we do until I’m told otherwise. I know 4.X has a different interface for the switching ASICs, so I’m thinking the SwOS will be built off of that. A manageable gig switch of…who knows how many ports. I’m hoping they go all the way and release a 24 or 48 port guy. Though they may be aiming more for a lower density, high function, low price gig switch.
Perhaps Normands can elaborate, if he is allowed to do so at this point?





