we love networks gladman has been teaching cisco for about five years right now, at the moment the internet is his class room, we are intending to offer various interactive cisco training resources and learning environments here which will not only support to the Cisco Networking Academy, but also create a support group for those with cisco related issues.. keep in touch
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By gladman, on November 10th, 2010
if you have even just a passing interest in networks and the workings of the internet you will probably be aware of it’s impending collapse due to the finite number of ipv4 addresses, about 4 billion not to be exact, recent work by Geoff Huston suggests that ipv4 exhaustion is no longer something we can avoid dealing with, Niall Murphy et al, calculate that even if all currently available measures are implemented, this will occur within 5 years.
Wikipedia overview of address depletion
The effects of exhaustion are currently hot potatas, no doubt Regional Internet Registries will have to be a lot more circumspect when handing out blocks of the remaining address, and the ISP’s will more than likely have to charge more to ensure that they maintain their own profitability, but the most interesting aspect of exhaustion to us Cisco students is the affects that will be wrought upon the routing architecture of the internet,
as you probably know, CIDR and VLSM allowed network designers to get away from the strictures placed on them by the Classful structure of the IP addressing scheme, the introduction of the ‘classless system’ allowed for much greater flexibility, as networks no longer had to inhabit xx and furthermore the core routing tables of the internet were able to advertise summary addresses for contiguous blocks of IP thus reducing the number of entries and allowing for growth, check out this excellent wiki-p article on the full shebang.
ipv6 is currently the only agreed method, that will maintain the structure and the scalability of the internet as we know it, but ipv6 has been on the table since 1998 and still it fails to be implemented in around 98% of the nodes on the internet according to a 2009 study by Google (peep the link for more info)
intially the use of 6to4 tunneling and the development of ‘better’ or new types of Network Address Translation, 6to4 or 4to6 maybe, possibly InternetCore Address Translation, should prevent wholesale collapse in the short term, but the lack of a coherent and unified approach will potentially cause as many issues as the problem itself.
One point made in Murphy’s article is that the current Internet management system, is a fairly democratic setup, but dwindling resources, can cause arguments and bad blood between co-habitants, even more so when those resources are so economically significant.
so in closing, this article makes two points, the first is that the internet is a community, and as such it is important that all members of this community a: know what’s going down and b: are free to get involved in shaping and developing it’s future…
By gladman, on January 25th, 2009
the latest release of wordpress is absolutely gorgeous, the back office just got a whole lot more.. useable, all the features are right there a click away, easily navigable (!) visually striking, and bristling with new features, the most user friendly of which is the auto-upgrading of plugins, theoretically you won’t need ftp any more, this feature of course doesn’t work fully yet, php-exec is having problems with it, and if you have any extra code and pix in the plugin directory, back it up, as some will overwrite everything and give you a plain, non-customised version of it..
By gladman, on November 16th, 2008
wow, new browser new internet, when i first installed chrome i felt sick, like i’d let something loose in my system, we have to understand that installing chrome, means we have ‘joined’ google, and that we are now a node in their system, a reverse virtualisation project whereby 10 bazillion machines will harvest and reap our sad little lives for all our keywords our content and eventually our souls..
but then i started using it, and god if it doesn’t make firefox seem like a fat old daddy, with footprints to match, loads of things didn’t work to begin with, but as we progressed things started getting fixed and it would appear that it’s updating itself without asking [confirm / deny]. the bloody java plugin totally doesn’t work though, this guy says he has a fix, nope.. that didn’t work
anyway, i still think we’re getting pimped…
By gladman, on September 21st, 2008
so after five years of being CCNA i finally took my first (real) steps into CCNP land, i was all set to throw in the towell, no cash, running out of time, no equipment blah blah and toxic came round and gave me a well needed kick in the raas, and plugged me in to gns3, so i got stuck in, and on saturday i got 877, which i was pleased with, i got 766 first time round…
as you probably know, the ccna needs re-certifying every three years, which kinda makes progression a must, last time i re-certified with the Wireless Lans for Field Engineers, this time i chose the BSCI or CCNP 1, i didn’t book my exam until the last minute, so i was a bit stressed about what would happen if i didn’t get it first time, my ccna was due to expire two days later so i re-booked that very night and my certifcation appeared held open until the result for my re-booked exam came through, a bit risky but i didn’t hae much choice as i’d left it so late.. unfortunately though, the cert bods went back and expired my CCNA, so now i gotta do it again… hey ho, back to the books
By gladman, on September 2nd, 2008
we here at cisco biscuits, are huge fans of simulation, why spend million pound on a room full of router death when for absolutely no money you can have a network that would make the average Service Provider quake in their booty, big respect to toxic for his stirling work in helping me get all this running back at the internest GNS3 is the logical culmination of the stirling work done by Christophe Fillot at the University of Technology, Compiegne, France, the dynamips Cisco® router emulation software.  GNS3 packages the most useful routers, from the humble 2600′s to the fearsome 7200′s in a handy network designer, and allows them to run full ios images, and allows you to telnet, or ssh to each… so you are no longer using a simulator, you’re using a virtual machine, which you could, in theory, stick in the middle of an ISP network and save millions on hardware and electricity… i’ve been spanking the lab work for the bsci using gns3 and so far have configured multiple ospf areas, all flavours of bgp routing and route mapping, so far the only thing i can’t do with it is run IGMP with real switches, as GNS doesn’t (yet?) support switches, if you have a big bag of lab work to rinse out, this really is the answer, while Packet Tracer is good, it still has the limitations of any simulator, and it can be a proper pain in the arse to use..
general advice when running GNS3
- go out and buy the fastest machine you can afford with as much memory as humanly possible, as the hardware is all being emulated, mucho mips and flops are required, especially when you running 3 or 4 routers. i am running gns3 on an athlon xp 1800 with one GB of RAM, and one or two VM routers will sometimes lock up, or features refuse to work, i tend to kill all non mission critical processes while running
- choose the smallest IOS image you can get away with, when we first set up GNS we ran the advanced ip services image on 7200 routers [because we could] but the size of the image thrice multiplied was too much for my puny machine to cope with and much paging and CPU maxing was in evidence, toxic found a nice 2691image that so far has supported all of my BSCI needs [he later tells me that this image is a bit cranky]
- installation on windows gave us a little distress [toxic reports that it behaves very well in linux {no surprise there}] and the GNS3 implementation of the dynamips console still doesn’t work properly on my machine, and due to the tendency to crash i have been saving my topologies and configs at regular intervals, to enable saving of configs you must create a new project, after that all saves will automatically save configs, you will lose connection to all routers when you create the new project however, so ensure that a copy run start is performed so that when you re-open your project file you haven’t got to re-configure [truly a real killer on some multiple BGP beast at 2 in the am]
more..
so my man toxic hooked me up with a 64 bit athlon machine with a whole 2GB, RAM up session, after nuff fussing and fighting with ubuntu, didn’t like my ati viddy card, and gns3 is still kinda experimental for ubu, i gave in and went the xp64 route..
the first probelem was the path to dynamips, it being a 32 bit app, it gets installed in the Program Files (x86) directory, so you need to add the (x86) bit, so far so good.. now the hypervisors [that's what gns calls the virtual routers] are running but the console isn’t working, telnet is not happening, so i downloaded putty and stuck that in the path in gns3′s general settings and boom, the machine is cranking, three 7200′s running the daddy c7200-advipservicesk9-mz.124-4.T1,
so next up is to get gns talking to the ethernet loopback adapter on the xp box and via that hopefully we can get it talking tothe free TACACS+ server that’s floating about on the net, c’est la, see you when it’s done
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