how routing protocols update their routing table with entries from their neighbors using classful routing protocols

[vks.cisco]

Please someone describe how routing protocols update their routing table with entries from their neighbors using classful routing protocols

Break the explanation in two parts

1. Theory in short

2. Example

Please help

[Rolf Fischer]

What's wrong with the answers you've already got?

https://supportforums.cisco.com/thread/2252503

https://supportforums.cisco.com/thread/2252805

You didn't rate a single answer so far; the 2 ratings in the first discussion did I in your stead, because Giuseppe and Jon provided excellent expanations!

[vks.cisco]

Fischer

Fine all the above but I dont want to harass them more.

Secondly despite those explanations I am bit confused with output I am seeing.

See My Questions to Jon

Jon is asking me to get someone else's help

If you can then its my fortune, and really I know the theory but maybe I can't draw the network scenario to really understand.

May be you can help me

[devils_advocate]

Without being rude, this sort of information is available on hundreds of websites.

Perhaps it may be an idea to get hold of a CCNA book and have a read?

People on here are happy to help with genuine troubleshooting issues or even to help someone understand something they are struggling with but the question you posted seems to suggest you have done none of your own research beforehand.

[vks.cisco]

D A

I already mentioned I know all the theories but could not become comfortable with few confusing aspects, I am mentioning below.

If you can answer then its well and find.

I am confused with fact-

1. when router already have interface configured with a particular class of network with say /16 mask given 10.0.0.0 network, but will it accept other routers updates concerning 10.0.0.0/8 network.

I think no it will not since it already knows about 10.0.0.0 network which is directly connected,

But as per theory when it receives update it applies mask which is configured in its own interface (in our example /16)

And secondly my routers routing table output makes me more confused.

10.0.0.0/8 is variably subnetted, 5 subnets, 2 masks

R       10.1.0.0/16 [120/2] via 10.4.5.2, 00:00:04, Serial0/0

C       10.2.0.0/16 is directly connected, FastEthernet0/0

R       10.3.0.0/16 [120/1] via 10.4.5.2, 00:00:04, Serial0/0

C       10.4.0.0/16 is directly connected, Serial0/0

C       10.6.6.0/24 is directly connected, FastEthernet0/1

and worst even the 10.6.6.0 network is not shown elsewhere despite the fact other C routes are being shown.

Please explain

[Jon Marshall]

Vishal

Firstly i didn't actually ask you to get help from others i merely suggested in a thread that others may be able to provide outputs but it seems you are able to lab these things up anyway so i'm not sure what you are asking for in that regard. There is nothing wrong with asking questions as that is what CSC is all about but you have asked a question in this forum (LAN) about the difference between classful and classless routing and forwarding and this has already been answered in the WAN forum. If the answer didn't make sense then i apologise but i'm not sure how else it can be explained to be honest. It would have been better to simply add a link to back to that thread if you wanted a different explanation rather than start a whole new one in this forum.

In terms of your specific query above you didn't give me time to answer in the thread in WAN. For things like this Google is your friend. So as an example i typed in "rip routing updates" and the fourth link pointed me to this Cisco doc -

http://www.cisco.com/en/US/tech/tk364/technologies_tech_note09186a0080093fd8.shtml

If you look at the Send Updates section and work through the rules then you can see that the reason 10.6.6.0 255.255.255.0 is not being advertised is because it has a different subnet mask to the interface that sources the update ie.10.4.5.1 255.255.0.0.  When you changed the mask for 10.6.6.0 to 255.255.0.0 then it was advertised.

This is why it is important to use a consistent subnet mask for the same major network with a classful routing protocol.

No one is saying you should not post questions, please feel free to do so. But also you need to make a bit of effort yourself to find the answers and please don't post the same questions across multiple forums.

Jon

[vks.cisco]

Dear friend

I thank a lot to your for your kind support, its not that I didn't tried out, the many i read articles it makes me more hopeless and confused, so I took the direct approach to ask you people and as far I usually draw and shown you the output of all the questions I ask you (that's proof I am trying my best).

May be the time teaches me and would be my best answer.

I need help from you all experts since I have lot to do and proof myself

And I am sorry for not rating your answers as one of the Guy over here pointed, I was afraid that marking the Answer as correct would close the discussion. So I kept all those till I got the final answer.

Anyhow I would like to add you as friend. Please go ahead, Hope you won't mind adding me as friend too.

Thanks