eigrp and load balancing issue

JacobGates

I am doing a lesson here: 5-5 Configuring EIGRP « Free CCNA Study Guide Free CCNA Study Guide which as you can see sets up eigrp in a network with 5 routers. I have gotten all the way to the bottom of the page (where it says "EIGRP load balancing and maximum hops") with no problem until I check the ip route on RouterC and I don't get the same output. It shows on the lesson that there should be 2 paths listed to reach 192.168.4.0/24 (one through 192.168.6.5 and another through 192.168.2.2) but that is not what my router is saying. It's only showing the path through 192.168.2.2. What's going on? Do I need to post my configs of all my routers? If so I can. Also I am doing all this in GNS3 with 3660 Cisco router image.

fredrikjj

You first need to understand why and when two routes to the same destination are installed in the routing table. Do you know this?

JacobGates

fredrikjj wrote: »

You first need to understand why and when two routes to the same destination are installed in the routing table. Do you know this?

I believe so. You can have one for the successor and the other as a feasible successor. And the other reason would be to load balance... which is splitting the information and sending it over 2 (or more) paths. Right?

fredrikjj

If you look at the routes in the routing table they have certain properties that are used to decide what gets installed in the case that there are multiple routes to the same destination. Remember that the goal of the routing protocol is to be select the "best" path to a destination.

That suggests that if you want multiple routes to the same destination, they must have certain properties in common, right?

JacobGates

fredrikjj wrote: »

If you look at the routes in the routing table they have certain properties that are used to decide what gets installed in the case that there are multiple routes to the same destination. Remember that the goal of the routing protocol is to be select the "best" path to a destination.

That suggests that if you want multiple routes to the same destination, they must have certain properties in common, right?

yes and both routes to 192.168.4.0 have a FastEthernet network and a serial network to go through and all on the same router types so it should be common right?

Magic Johnson

Check the topology table out and look at the costs.

fredrikjj

Yes, it looks like they should have the same metric. You now need to verify that Router C actually receives 192.168.4.0/24 on both of its interfaces.

JacobGates

how do I check that RouterC is receiving 192.168.4.0/24 on both interfaces? Can you ping through a specific interface?

devils_haircut

You can use an extended ping to specify both the source and destination address that you would like to use. The easiest way to do that is to just type "ping" and hit enter, then choose "y" for extended options.

CORRECTION: you can also just type "ping 10.1.1.1 so 192.168.1.5" to specify the source without having to go through all those options. "so" specifies the source address.

JacobGates

devils_haircut wrote: »

You can use an extended ping to specify both the source and destination address that you would like to use. The easiest way to do that is to just type "ping" and hit enter, then choose "y" for extended options.

I typed "ping" then the output was "Protocol [ip]:" not sure if this is what you meant but I tried to type y anyways and it said Unknown protocol. did I misunderstand?

Magic Johnson

JacobGates wrote: »

how do I check that RouterC is receiving 192.168.4.0/24 on both interfaces? Can you ping through a specific interface?

The network command/s should cover all the interfaces connected to networks you want to advertise. Maybe you have missed one on Router E? Also check that any of your interfaces you want EIGRP enabled on aren't passive.

JacobGates

Oh my god.... I feel so stupid right now. When Magic Johnson said to check Router E I typed 'show running-config' and as I was just skimming it I realized I accidently put 192.168.6.3 on the serial interface of Router E which is supposed to be 192.168.6.5. So I fixed it and now it's working like it should. Thank you all for trying to help me. In the end it was me making a stupid mistake.

devils_haircut

JacobGates wrote: »

but I tried to type y anyways and it said Unknown protocol.

Sorry, I should have been more clear. You want your protocol to be IP. When it asks if you want to use Extended Options, then you would answer "y" for yes.

Or you could just use the method I posted above "ping x.x.x.x so x.x.x.x" where the first IP is your destination and the second IP is your source.

Magic Johnson

JacobGates wrote: »

Oh my god.... I feel so stupid right now. When Magic Johnson said to check Router E I typed 'show running-config' and as I was just skimming it I realized I accidently put 192.168.6.3 on the serial interface of Router E which is supposed to be 192.168.6.5. So I fixed it and now it's working like it should. Thank you all for trying to help me. In the end it was me making a stupid mistake.

Hey the only mistakes that are stupid are ones we don't learn from!

In fact, if you don't make mistakes you don't learn, honestly the amount of times I've missed something or misconfigured or even as you put in a number wrong, it GREATLY enhances your troubleshooting skills.

JacobGates

devils_haircut wrote: »

Sorry, I should have been more clear. You want your protocol to be IP. When it asks if you want to use Extended Options, then you would answer "y" for yes.

Or you could just use the method I posted above "ping x.x.x.x so x.x.x.x" where the first IP is your destination and the second IP is your source.

Oh okay, yes, that worked. Thank you! that's really cool. I didn't know that command was so expandable.

Magic Johnson wrote: »

Hey the only mistakes that are stupid are ones we don't learn from!

In fact, if you don't make mistakes you don't learn, honestly the amount of times I've missed something or misconfigured or even as you put in a number wrong, it GREATLY enhances your troubleshooting skills.

Some very wise words there. I have definitely learned from that! Still feel really silly. I guess that is how we motivate ourselves not to do that again.

fredrikjj

JacobGates wrote: »

Oh my god.... I feel so stupid right now. When Magic Johnson said to check Router E I typed 'show running-config' and as I was just skimming it I realized I accidently put 192.168.6.3 on the serial interface of Router E which is supposed to be 192.168.6.5. So I fixed it and now it's working like it should. Thank you all for trying to help me. In the end it was me making a stupid mistake.

I don't think that you should just be satisfied with that solution. Reading the running config is not a reliable troubleshooting method, and you should have detected the nature of the error directly on Router C. I would recreate the error and then approach it more systematically from the point where you don't have the two routes that you expect in the routing table. What show commands would be appropriate to use and what conclusions can be drawn from those, etc.

Magic Johnson

fredrikjj wrote: »

I don't think that you should just be satisfied with that solution. Reading the running config is not a reliable troubleshooting method, and you should have detected the nature of the error directly on Router C. I would recreate the error and then approach it more systematically from the point where you don't have the two routes that you expect in the routing table. What show commands would be appropriate to use and what conclusions can be drawn from those, etc.

This is true. 'show ip protocols' would have been a better command as it shows you almost the complete configuration of the routing protocol. Or show ip eigrp interfaces. Your serial interface on Router E wouldn't have been listed.

JacobGates

fredrikjj wrote: »

I don't think that you should just be satisfied with that solution. Reading the running config is not a reliable troubleshooting method, and you should have detected the nature of the error directly on Router C. I would recreate the error and then approach it more systematically from the point where you don't have the two routes that you expect in the routing table. What show commands would be appropriate to use and what conclusions can be drawn from those, etc.

Magic Johnson wrote: »

This is true. 'show ip protocols' would have been a better command as it shows you almost the complete configuration of the routing protocol. Or show ip eigrp interfaces. Your serial interface on Router E wouldn't have been listed.

Yeah I guess you are right, I can't spend to much time reading running configs to find problems. But also I know the problem now and can relate it so I will know in the future to look for something that specific. If I had suspected it I might have done show ip eigrp interfaces but sense I didn't know what could be causing it then it never crossed my mind to check. I just noticed that will skimming it by accident this time.