CCIP BGP GNS3 TOPOLOGY
November 5, 2012 28 Comments
Just a quick update !
For all of you who have not seen BGP topology from this excellent CCIP INE series I am more than happy to present it to you :
This is how it is presented to us in the series :
And below is how it looks like in GNS3. Of course you can use the very top one however I do strongly recommend using below diagram while learning through this series as it teaches you a very important skill , well a few of them for that matter:
1 – Frame Relay switch and of course Frame Relay configuration
2 – Frame Relay subinterface configuration
3 – Building “something” while only having few devices simply connected together (definitely most valuable point)
4 – Router on a stick configuration
5 – Vlans configuration
6 – wonder if I’ve missed anything 🙂 ……
7 – and of course BGP !!
For all of you who have watched and practised with the CCIP INE BGP series with Keith Barker (link http://www.ine.com/self-paced/ccip/bootcamps.htm) which in in my opinion is the best series about BGP with in depth explanation about this technology I have noticed that many people are asking , see this thread (https://learningnetwork.cisco.com/thread/38332?tstart=0#203399) to post full topology , ip addresses , BGP AS’s and more used in this course.
I have to admit myself that BGP topology in this series can be a little hard to read and in order to create it in GNS3 or using real cisco equipment you really have to listen and watch very carefully each video and especially concentrate on the routing table on each device.
Well last weekend is just what I did cause we learn something new everyday , basides I thought to myself that being able to create exact same routes that Keith uses in the series by having only an output from the routing table whenever he issues “show ip route” or “show ip bgp” altough not very often 🙂 would be a great practise and a real fun challenge !
Above topology is what is required to practise and learn from this course and below are initial , very basic config files for each device.
When you look at these config you will notice that on routers R3,R4,R5,R6,R7 I have kept OSPF as shown in this course (of course use any other protocol you wish for an IGP) and BGP AS3 very basic config just to obtain connectivity between devices but half way through the series AS3 will be split into confederations so the config will have to be changed so feel more than welcome to change , amend anything you wish!
See below initial configs for each device:
See below GNS3 net file. Simply go to previuosly specified by you GNS projects folder on your hard drive , right click on a net.file , copy/paste the one below , change the image path to the one where you store your IOS images and change the workingdir path pointing to wherever you saved provided above configs , save it under another name to avoid removing your own file by mistake and there you have your BGP topology for the series. Launch GNS3 and begin your BGP adventure !
Once you’ve loaded this topology and issue sh ip bgp or sh ip bgp summary or sh ip bgp neigh 192.168.68.8 received-rou (Inbound soft reconfiguration not enabled for this to work) on R6 you will only see 2 prefixes that R6 is learning from R8 even though at the beginning of the video series it shows that in fact R6 should learn 7 prefixes and not 2
and below is how it looks like in the series
The reason for that is that the series starts with some devices already preconfigured like in this case R9 who’s learning all prefixes from R2 , is already preconfigured with a next-hop-self command for the neighbour R8 192.168.89.8 as otherwise all prefixes that R8 is learning from R9 will not show as “best routes > as seen below
which is why they will never be sent to R6 because R8 does not know how to reach them. In order to fix it we need to configure a next-hop-self statement on R9 for the neighbour R8
That way R8 will install all prefixes learned from R9 as “best > ” and therefore will advertise them to its EBGP neighbour R6
As you can see R6 is now learning all required networks from R8.
Another thing is the connection between the connection between R6 and R9 which is not visible in the series diagram however this connection does exist and is being configured and used later in the series.
Please go ahead and check on youtube at: http://www.youtube.com/watch?v=lwTzwFJEeM0&feature=youtu.be
Enjoy the series !
All the best!