Just another Cisco blog
Posts tagged Lab
RIP Lab #1
Apr 27th
This is the first in a series of lab posts I’ll be doing to prepare for the CCIE.
Today’s lab is from Narbik’s Volume One workbook. It’s a RIPv2 lab with some tricks thrown in. Here’s the topology:
(Click image for fullsize)
Click here for the initial configs
Here is task one:
1. Configure RIPv2 on all routers and advertise their directly connected interfaces. Ensure that these routers have full NLRI to all the loopback interfaces advertised into RIP. Ensure that all routers can ping all loopbacks.
Let’s go through the config:
R1: R1(config)#router rip R1(config-router)#ver 2 R1(config-router)#no auto R1(config-router)#network 10.0.0.0 R1(config-router)#network 1.0.0.0 R2: R2(config)#router rip R2(config-router)#ver 2 R2(config-router)#no auto R2(config-router)#network 10.0.0.0 R2(config-router)#network 2.0.0.0 R3: R3(config)#router rip R3(config-router)#ver 2 R3(config-router)#no auto R3(config-router)#network 10.0.0.0 R3(config-router)#network 3.0.0.0 |
Looks pretty simple, but I’m sure you guys see that this won’t work correctly. Let’s look at R2 and R3′s routing tables:
R2#sh ip route
...
R 1.0.0.0/8 [120/1] via 10.1.1.1, 00:00:15, Serial0/0
C 2.0.0.0/8 is directly connected, Loopback0
10.0.0.0/24 is subnetted, 1 subnets
C 10.1.1.0 is directly connected, Serial0/0
R3#sh ip route
...
R 1.0.0.0/8 [120/1] via 10.1.1.1, 00:00:06, Serial0/0
C 3.0.0.0/8 is directly connected, Loopback0
10.0.0.0/24 is subnetted, 1 subnets
C 10.1.1.0 is directly connected, Serial0/0 |
New Troubleshooting Lab Topology
Apr 3rd
The old topology I’ve been using for the weekly labs is pretty limited. I created a new one today which should keep us going for awhile. It’s relatively complex, it consists of two customer MPLS VPNs and lots of routing. The two customer VPNs also have internet access through one of their sites. We are simulating the internet with Peer1 and Peer2. Here’s the diagram:
(click image for fullsize)
I should have the first lab up early next week after I work out some issues I’m having. So tell me what you guys think.
Here’s the .net file:
New Troubleshooting .net file
Troubleshooting Lab #4
Mar 18th
Today is probably going to be another easy one, but I threw it together pretty quick. We’re using the same topology as last time. Same issue, users cannot communicate, but different problem.
You can run the .net on your own Dynamips server or you can use mine. Run the topology and login with username “tshoot” and password “tshoot”. This user only has privilege level 1, so show commands will be available, but show run will not be. You can also login with username: “shrun” and password: “shrun”, this will print the running config and boot you out. I would like to grant full privilege 15 access, but I’m worried about people messing with the configs, this is after all a public post. Obviously you could get around this pretty easily, but that would defeat the purpose. 
Here’s our topology:
(Click for fullsize)
Troubleshooting Lab #1
Mar 5th
This will be the first in a series of troubleshooting labs. I will post a topology and the issue I’m seeing. Hopefully you guys will attempt to solve it and post your ideas, questions and solutions in the comments.
We’ll start with a relatively easy one. Today we are having an issue with BGP neighbor relationships not forming.
Here’s our Topology:
Here’s R1′s config:
hostname R1 ! ip cef ! interface Loopback0 ip address 1.1.1.1 255.255.255.255 ! interface Serial0/0 description To R2 ip address 10.1.1.2 255.255.255.254 ! router bgp 5000 no synchronization bgp log-neighbor-changes neighbor 2.2.2.2 remote-as 6000 neighbor 2.2.2.2 ebgp-multihop 2 neighbor 2.2.2.2 update-source Loopback0 no auto-summary ! ip route 0.0.0.0 0.0.0.0 10.1.1.3 |
And R2:
hostname R2 ! ip cef ! interface Loopback0 ip address 2.2.2.2 255.255.255.255 ! interface Serial0/0 description To R1 ip address 10.1.1.3 255.255.255.254 ! router bgp 6000 no synchronization bgp log-neighbor-changes neighbor 1.1.1.1 remote-as 5000 neighbor 1.1.1.1 ebgp-multihop 2 neighbor 1.1.1.1 update-source Loopback0 no auto-summary ! ip route 0.0.0.0 0.0.0.0 10.1.1.2 |
Now some show commands:
R2#sh ip bgp summ BGP router identifier 2.2.2.2, local AS number 6000 BGP table version is 1, main routing table version 1 Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd 1.1.1.1 4 5000 0 0 0 0 0 never Active R1#sh ip bgp summ BGP router identifier 1.1.1.1, local AS number 5000 BGP table version is 1, main routing table version 1 Neighbor V AS MsgRcvd MsgSent TblVer InQ OutQ Up/Down State/PfxRcd 2.2.2.2 4 6000 0 0 0 0 0 never Active |
We see that the relationship will not form. You guys tell me why.
I’m attaching the .net file, with it and the configs above you should be able to replicate this easily.
The Troubleshooting Lab #1 .net file
(Don’t forget to change your paths)
BGP Communities
Feb 4th
Today’s post is about BGP Communities. Here is an explanation of them from Cisco:
“A community is a group of prefixes that share some common property and can be configured with the BGP community attribute. The BGP Community attribute is an optional transitive attribute of variable length. The attribute consists of a set of four octet values that specify a community. The community attribute values are encoded with an Autonomous System (AS) number in the first two octets, with the remaining two octets defined by the AS. A prefix can have more than one community attribute. A BGP speaker that sees multiple community attributes in a prefix can act based on one, some or all the attributes. A router has the option to add or modify a community attribute before the router passes the attribute on to other peers.”
Here is a table listing the Well Known Communities from Cisco:
Recent Comments