Some More Troubleshooting Fun With EIGRP

Recently I got this request from a friend working on CCNP. He was looking for some troubleshooting labs. So I thought to help him out with couple of labs and to other people who are preparing for CCNP TS exam.


So to add some fun I created this small troubleshooting lab last night. Below is the topology :

R1 should be able to reach R4's loopback and vice versa. For verification point of view the command -  R4#ping 1.1.1.1 so lo0 should have 100% success rate. Also R4 should be able to telnet R1 and get login prompt.


Here are the initial configuration files and GNS topology for you guys :


http://hotfile.com/dl/124210052/99638e1/EIGRP_ISSUE.rar.html


Also recently I saw a nice post from CCIE Anthony at blog.ipexpert.com which might help you along the way:


http://blog.ipexpert.com/2011/07/10/troubleshooting-eigrp-adjacencies


Again... Being a good network engineer, Avoid using "sh run" and instead try to find and fix the problem using other "show" commands.


HTH...
Deepak Arora

MPLS VPN Troubleshooting - Bob Calling For Help !!!

Finally after a long gap I am back with my tutorials and labs for learning and fun. Few weeks back I posted MPLS VPN Lab topology, So before explaining it step by step I thought to bring it as challenge for people who already know MPLS from R&S lab prospective and are looking for some troubleshooting stuff on it. So I am going to bring today a MPLS VPN TS challenge for them.

So our old friend BOB was sitting free on monday after noon and then he received an email containing the following topology and two fault tickets.

The topology has got two different MPLS VPNs. One is VPN blue and another is VPN red. VPN blue site 1 should be able to reach VPN blue site 2 and vice versa and same case with VPN RED. But both VPNs shouldn't be able to talk to each other.


Below is the link to download initials for lab along with GNS topology and IOS version details to run it. See if you can help BOB with this problem.


BTW.... Avoid removing configurations completely. Also being a excellent engineer, don't use "sh run" to show your skills.


http://hotfile.com/dl/123139611/4ae9ec6/MPLS_VPN_LAB_final_config.rar.html

HTH...
Deepak Arora

MPLS Layer 3 VPN Troubleshooting - My Personal Approach

While I am going for my Second CCIE R&S Lab attempt soon, I thought before leaving I must post my MPLS TS Strategy in general despite of fact I will get in my TS lab or not :

Ofcourse people who wanna know what went wrong with First attempt, here is the summary :  http://ieoc.com/forums/t/15436.aspx

Below are the summary steps:

Step 1

=======

CEF is running on MPLS enabled routers

sh ip cef


Step 2
======

loopback advertised into IGP on CE, Also Check IGP configuration like "no auto summary" and "redistribution seed metric, "autonomous system number in EIGRP VRF Configuration".

sh ip int b | e una

sh run | s r [eor]

Step 3
======

Check if VRF is created and applied to proper interface

sh run | s vrf

sh ip vrf detail

sh run int

Check if CE routes are coming to PE

sh ip route vrf


Step 4
======

Check for VRF route target import and export

sh run | s vrf

Step 5
======

Check if LDP is running all over, mpls ip is configured on MPLS facing interfaces.

sh mpls interface

sh mpls ldp neighbor

Step 6
======

Check for MP-BGP and IGP redistribution,

sh run | s r b

sh run | s r [reo]

Check for redistribute metric, For OSPF look for "match internal external 1 external 2" , For eigrp "redistribution metric" should be mentioned.

Step 7
======

Check for MPBGP Config on all routers, look for things like RR config, neighbor activate, send community extended or both, no synchronization, no auto summary, remote as, update source loopback 0

sh run | s r b

sh ip bgp vpnv4 all summ

sh ip bgp vpnv4 all

Step 8
======

Check for Control plane issues on all routers like:

1. ACL

sh access-list

2. CoPP

sh policy-map control-plane

3. Distribute List, Offset-List

sh run | i distribute offset

4. Route-map

sh route-map

5. Rate Limit

sh run | i rate

6. Next Hop and Route Recursion Issues

7. IGP Timers and Password mistmatch issues

8. PBR

sh run | i policy


HTH...
Deepak Arora

MPLS VPN Lab - All you need to know for CCIE R&S (Coming this weekend)

Back To Back Frame Relay - Old Days Stuff

So today I am gonna discuss some old school stuff called "Back To Back Frame-Relay". So the first thing coming in your mind would be "What Exactly is that ?" & Second thing will be "Why do we need this ?"

So coming to Idea of why do we need this. Actually in old days and galaxy far far away everyone was running P2P circuits. As you might be aware on those P2P links we use to run PPP. Though Cisco was cool enough and came up with HDLC.

But the problem was that there was no Native QOS Mechanism supported by PPP or HDLC by own. And of-course in those days we didn't have QOS based on MQC. 


So one day one evil engineer came up with idea "Alice - Hey Bob ! I know Frame-Relay supports a native QOS mechanism called FRTS(Frame-Relay Traffic Shaping) so why don't we use to apply QOS on our P2P links? "


But Frame-Relay on Point to Point Circuits ? How we gonna do that ? What we gonna name this thing ?

Hmmm... We call this Back To Back Frame Relay :-)


After this cool story now lets take a look at our simple topology and configuration we require.

 

 

 

We disabled Keep Alive in this implementation since there is no Frame-Relay Switch involved in topology(or in P2P links). Also on both sides we must use the same DLCI number.

So now you know that Back To Back FR was only method in existence in old days to implement QOS on P2P links for stuff like VoIP etc. All you gotta do is to create "map classes" to apply FRTS on these links.

HTH...

Deepak Arora