Scenario:
Jack and Joe both have important information to share with each other but they don’t have a direct connection between them. Tori agreed to help out and so they setup a Frame-Relay network to share information. EIGRP (Enhanced Interior Gateway Routing Protocol) is used as the routing protocol to dynamically learn new networks. Configuring EIGRP should be straight forward but Joe and Jack are complaining that they are unable to reach other’s networks…time for you to fix it!
Goal:
- All IP addresses have been preconfigured for you.
- Every router has a loopback0 interface:
Tori: 1.1.1.1 /24
Joe: 2.2.2.2 /24
Jack: 3.3.3.3 /24 - You are not allowed to make any changes to the frame-relay configurations.
- Configure EIGRP AS 123 on all routers, advertise all networks.
- Ensure router Joe and Jack can see each other’s loopback interfaces. Test this by sending a ping that is sourced from the loopback0 interfaces and destined for the other loopback0 interface.
It took me 1000s of hours reading books and doing labs, making mistakes over and over again until I mastered all the protocols for CCNA.
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IOS:
c3640-jk9s-mz.124-16.bin
Topology:
Video Solution:
Configuration Files
You need to register to download the GNS3 topology file. (Registration is free!)Once you are logged in you will find the configuration files right here.
The How to Master series helps you to understand complex topics like spanning-tree, VLANs, trunks, OSPF, EIGRP, BGP and more.
Written by René Molenaar - CCIE #41726
Tried disabling split horizon…. No Luck… 🙁
Any clues?
So what is working / not working? What does your config look like?
Got it solved… Needed to enter Frame Relay Maps on Joe & Jack… not sure if that was supposed to be present already or was it a part of the exercise???
You don’t have to enter frame relay maps.
You’re right Deep, you have to map the the spoke routers to each other!
Hi Guys,
I achieved the goal by just disabling the split horizon on Tori, is that correct or not. Because you said not make any changes in Frame Relay Configuration so that’s why I didn’t put any frame map command.
Regards
There is no need to modify or add any frame-relay statements.
You have to specify the AS# where you disable split horizon on.
(config-if)#no ip split-horizon eigrp 123
I believe just entering “no ip split-horizon” will only apply to RIP routing.
Split Horizon is the answer to this solution. We have multipoint frame-relay here and prefixes learned from the spokes are not advertised.
Disable split horizon on router Tori is what you need to do, make sure you pick the “no ip split-horizon eigrp 123” command otherwise you disable it for RIP.
Fixing the problem with frame-relay statements is possible but not the solution since the goal states “You are not allowed to make any changes to the frame-relay configurations.”.
Good luck!
Rene
Hi everyone,
I can ping Jack and Joe from Tori. but can’t ping from Jack to Joe or vise versa.
here is my configuration:
Tori:
” no ip spilt-horizon eigrp 123
router eigrp 123
network 192.168.123.0
network 1.0.0.0 ”
Joe:
router eigrp 123
network 192.168.123.0
network 2.0.0.0
Jack:
router eigrp 123
network 192.168.123.0
network 3.0.0.0
do I miss something and therefore can’t ping between Jack and Joe?
Thanks!!!
router eigrp 123
network 192.168.123.0
network .0.0.0
Did you disable split horizon on the physical or sub-interface?
Also, what is the next-hop IP address for the networks you are unable to reach?
Hello,
I can do this part:
Ensure router Joe and Jack can see each other’s loopback interfaces. Test this by sending a ping that is sourced from the loopback0 interfaces and destined for the other loopback0 interface.
But if a send a ping without specifying the source, then the ping fails. Any one can explain this for me?
—output–
JACK#ping 2.2.2.2 so 3.3.3.3
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
Packet sent with a source address of 3.3.3.3
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 24/40/52 ms
JACK#ping 2.2.2.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
…..
Success rate is 0 percent (0/5)
JACK#
[b]TOO easy ! made me feel good though[/b]
@william2
This stumped me too. I found out the following:
Standard ping uses the outside IP for sending IP. “Ping 2.2.2.2” will use 192.168.123.3 as source (Jack outside IP). The return packet from Joe will be sent to 192.168.123.0 network, which is local. The packet will be sent to Layer 2 for processing. Layer 2 (Frame Relay) does not have a mapping for 192.168.123.3 and inverse ARP is disabled.
Result: packet fails.
This is why adding frame relay maps between Joe and Jack allow the ping to succeed.
The explanation of strasser is the perfect answer to this lab. That’s why the ping from the loopback interface works and from the physical interface it doesn’t.
If you want proof you can debug your frame-relay packets and you’ll see it has encapsulation errors because there’s no mapping for the physical interface IP address.
Thanks strasser for the explanation.
I thought enabling inverse-arp without frame-relay map would solve it; but it didn’t seem to work. What am I missing here?
thanks!
Frame relay has two methods of doing the Layer 2 (DLCI) to Layer 3 (IP) mapping:
– Inverse ARP
– The Frame-relay MAP command.
Inverse ARP will work if you have your IP addresses on the physical interface. You can check the mapping by using the ‘show frame-relay map’ command. Check your router to see if it has a mapping…
If you are using sub-interfaces you need to do the mapping yourself…there is no way for your router to tell to which sub-interface the DLCI belongs.
[color=red][/color]I did a [color=purple]no ip split-horizon eigrp 123[/color], why is it still showing [color=red][color=blue]Split horizon is enabled[/color][/color]?
interface Serial0/0.123 multipoint
ip address 192.168.123.1 255.255.255.0
no ip split-horizon eigrp 123
TORI#show ip int Serial0/0.123
Serial0/0.123 is up, line protocol is up
Internet address is 192.168.123.1/24
Broadcast address is 255.255.255.255
Address determined by non-volatile memory
MTU is 1500 bytes
Helper address is not set
Directed broadcast forwarding is disabled
Multicast reserved groups joined: 224.0.0.10
Outgoing access list is not set
Inbound access list is not set
Proxy ARP is enabled
Local Proxy ARP is disabled
Security level is default
[color=red]Split horizon is enabled[/color]
You disabled split horizon for EIGRP but the show command shows you split horizon for RIP.
Hi Rene,
Is there any show command to show that split horizon is disable for EIGRP? Sorry correct if I am wrong, from your video demonstration you did a
TORI#show ip int Serial0/0.123
and it shows that Split horizon is enabled before you proceed with ‘[color=red]no ip split-horizon eigrp 123[/color]’ input
interface Serial0/0.123 multipoint
ip address 192.168.123.1 255.255.255.0
no ip split-horizon eigrp 123
But why do we do a show ip int Serial0/0.123 when this (Split horizon is enabled) apply to RIP?
Thanks,
You are right, this is a mistake I made…if you look at the interface we are looking at RIP split horizon, not for EIGRP. I’m not sure which show command we can use to check if EIGRP split horizon is enabled or disabled…hmm…
Starting with IOS 15.0, you should have the requested information (EIGRP split-horizon enabled or not) with this command:
#show ip eigrp interfaces detail
from
[code]https://learningnetwork.cisco.com/thread/24641?start=30&tstart=0[/code]
Thanks Rene,
Thanks guys… I thought I suck, explanation here make things clearer and brighter 🙂
I had to add maps because without it the Jack and Joe routers would not even be able to ping each other, let alone ping the loopbacks.
@rene
just one question
when i start eigrp on router TORI and JOE. it automatically forming neighbor with each other .by sending hello on 224.0.0.10 address which is multicast address
how can a frame-relay network allow passing multicast packets through it . it should be sudo broadcast right!! or typing manual neighbor will sent unicast messages to each neighbor.
please can some one explain it..
@rene
just one question
when i start eigrp on router TORI and JOE. it automatically forming neighbor with each other .by sending hello on 224.0.0.10 address which is multicast address
how can a frame-relay network allow passing multicast packets through it . it should be sudo broadcast right!! or typing manual neighbor will sent unicast messages to each neighbor.
please can some one explain it..
hello mayank…
if you type show frame-relay map you will see the broadcast keyword (in the background you are right, it sends unicast to all neighbors)
Question. Why is each interface configured for multipoint? vs. the EIGRP over frame-relay lab with multipoint where only the hub is multipoint? I don’t see this configuration in your mastering CCNP route book or any lab. Please explain. The only answer I come up with is that the Curly/Larry have configs on subinterfaces.
why i disable Split horizon ??
If updates need to be sent out the same interface on which they arrived, you’d generally need to do that.
Hi Rene,
I have having issues in running your labs, when even I open in GNS3 , I get a message on all the console screen
Connected to Dynamips VM “R1” (ID 2, type c3600) – Console port
Press ENTER to get the prompt.
ROMMON emulation microcode.
This affects me to practice any of your lab, your quick suggestion would be highly appreciated.
I have an IOS c3640-js-mz.124-10.bin and have also updated with new version
Thanks
Vikash