Been reading up on multicast this last week. This is a completely new topic to me. I have never come across it before with the exception of Link-Local Multicast being used by routing protocols.
The way it was explained, seems simple enough to understand the basics but I get the feeling its considerably more complicated that I am led to believe.
The basic jist from what I understand is you have 2 main different modes of operation Source Tree and Shared Tree. These relate to the different PIM modes set on the router – PIM being the standard multicast routing protocol.
Source tree relates to Dense mode, the way I remember this is that every multicast stream wants to talk to the source router, creating a lot of dense flows on the network. Shared tree relates to Sparse mode on PIM.
I remember this one as multicast shares the load with the Rendezvous Points (RPs)dotted about the network creating less flows making the traffic more sparse. RPs are only configured in Sparse mode and provide a point for flows to travel to pick up the multicast stream instead of streaming directly from the source.
As usual there is an exception to these two standard modes, in Cisco’s terms it is SPARSE-DENSE-MODE.
Sparse-mode or Sparse-dense-mode allows the use of AutoRPs without statically assigning them throughout the network – as if you have a large network and one of the RP changes – this could be a lot of configurations you need to adjust to the new RP. Using AutoRP allows the network to find the RPs automatically without statically configuring them.
That’s what my take is from it anyway.
I also haven’t had much rack time recently as its mainly been reading up on technologies. Refreshed my knowledge on IPv6 from my CCNP which was good as all the labs now are dual-stacked with IPv4 and IPv6. I have however configured my rack as close to the new INE rack as possible just missing 2 routers at the moment.
My other books arrived that I ordered off Amazon at bargain prices, so now I have Routing TCP/IP Volume 1, Cisco LAN Switching, Troubleshooting IP Routing Protocols, Developing IP Multicast Networks, End-to-End QoS, and Catalyst QoS – all hardback and in near perfect condition, totalling under £100 – BOOM!
What else?…….oh yeah another lot of RAM and CF cards arrived today so have upgraded 2 more 1841’s to 384MB RAM and 64MB flash. This gives me a total of 6 x 1841s running 15.1 IOS code, I have one more running 12.4 and a 3845 running 15.1.
Also ordered another v06 1841 with 256/64 off Ebay for £23 so that will give me nearly 10 routers routers running IOS 15.1 at that point – which is good as the new INE v5 Advanced Technologies lab has a setup of 10 routers.
Cisco live in San Francisco was on last week and was tuned into that for a lot of it – had it on at work in the background. I was definitely jealous – it looked awesome and so much talent in one place!!!!! I found it really interesting listening to the seminars and keynotes people were giving.
There was certainly a lot of focus on SDN and the Internet of Everything #IoE – basically how every business was going to be a technology business including things like farmers, vineyards etc also how every device was going to be connected to the Internet like home lights, fridge, parking spaces to find a spot etc
It was really interesting to hear what they had to say about it and Cisco’s take on it. SDN is something I think I am definitely going to look in to, to keep up with the market – but will wait before looking at any form of certification because in my opinion it just isn’t mature enough yet – but there are definitely some exciting changes happening very soon with networking.
Just going back to my lab set up, I have discovered the wonderful world of router menus in the last few weeks – wow these things are useful!!! I now have a menu setup on every router on loading so as soon as I console on to the router it asks me what configuration I want to load or if I want a blank one. This then uses the configure replace command to load a saved config on to the router.
Wow amazing! seriously saves me some time. I set one up on my Access Server so that it gives me direct access to all my kit at the press of a menu number. This connects me to my router, then when exiting the router (using the usual CTRL+SHIFT+6 and X), it brings me straight back to the Access Server asking what router I want next – again, another time saver.
If I can, I will post the code somewhere for you to have a look at and re-use if you like. (Update – this can be found under the Router Menus section under Tutorials)
I have also stumbled on the use of Evernote. Its one of those apps that i have had installed on my iPad for about 18 months and never used – literally – just because i didn’t know what you could do with it. Well now I have played about with it I am really impressed.
I have started keeping all my study flashcards and notes on there along with any books, topologies or useful websites that I wanted to keep clipped. Not just for my CCIE but for anything networking in general that looks interesting. I also have installed the app on my laptop so can keep it all sync’d upl. Very handy!!
Anyway that’s all for now, will get back to studying and post again soon – hopefully will have another router by then as well to add to my collection.
May 24