My Cisco Virtual Lab Topology I

I have real Cisco routers and switches but most of the time I rather use virtual devices based on Dynamips. They are portable with my laptop, don't consume additional electricity and provide me with and environment to test features anywhere I go with my laptop. I use it to test QoS, MPLS, IP routing (with OSPF, EIGRP, BGP), gatekeepers configurations, load-balancing, etc. It is just as having the real thing with you.

For example, during my last trip I found myself running 15 routers on my laptop, doing a BGP load balancing configuration validation for a service provider. (Well, I managed to do the job but my laptop's battery was totally drained in little bit more than an hour). But the idea is that, it is a really flexible solution. (BTW, I run Linux so I don't have the memory limitations that the Windows instances have.)



In my case, I have various network files for various topologies. This "Topology 1" is the one the I most commonly use for testing of features, etc. Most of the examples and tips on this site will be tested using this topology as well.

When designing a "physical" virtual topology I try to make them flexible so that I can reuse them on different scenarios without the need to recreate them.

I use the following as my basic Cisco Virtual Lab Topology I

This topology, while simple, is very powerful. With it I can simulate a huge variety of topologies and arrangements. If you look closely you may find hope-and-spoke, star topologies, linear topologies, mixed topologies, etc.

This is the "topology1.net" file.

#
# START OF FILE
#
autostart = False
[localhost:7200]

workingdir = /path/to/my/workingdir/topology1

[[3640]]
image = /path/to/my/image/image_name-extracted.bin
idlepc =
ram = 128
rom = 4
iomem = 5
mmap = False #Force to run in real memory
ghostios = True
exec_area = 64
nvram = 128

[[ROUTER R1]]
model = 3640
console = 2000

slot0 = NM-4E
slot1 = NM-4T

s1/0 = FR 1
s1/1 = R2 s1/1
s1/2 = R2 s1/2
s1/3 = R3 s1/3

e0/0 = SW 11 # Or E0/0 = NIO_linux_eth:eth0
e0/1 = SW 12
e0/2 = SW 13
e0/3 = SW 14

[[ROUTER R2]]
model = 3640
console = 2001

slot0 = NM-4E
slot1 = NM-4T

s1/0 = FR 2
e0/0 = SW 21
e0/1 = SW 22
e0/2 = SW 23
e0/3 = SW 24

[[ROUTER R3]]
model = 3640
console = 2002

slot0 = NM-4E
slot1 = NM-4T

s1/0 = FR 3
s1/1 = R4 s1/1
s1/2 = R4 s1/2

e0/0 = SW 31
e0/1 = SW 32
e0/2 = SW 33
e0/3 = SW 34

[[ROUTER R4]]
model = 3640
console = 2003

slot0 = NM-4E
slot1 = NM-4T

s1/0 = FR 4

e0/0 = SW 41
e0/1 = SW 42
e0/2 = SW 43
e0/3 = SW 44

[[FRSW FR]]
3:304 = 4:403
2:204 = 4:402
2:203 = 3:302
1:104 = 4:401
1:103 = 3:301
1:102 = 2:201

[[ETHSW SW]]
11 = access 100
12 = access 200
13 = access 300
14 = access 400

21 = access 100
22 = access 200
23 = access 300
24 = access 400

31 = access 100
32 = access 200
33 = access 300
34 = access 400

41 = access 100
42 = access 200
43 = access 300
44 = access 400

#
# END OF FILE
#
For more information visit:

Dynamips:
http://www.ipflow.utc.fr/index.php/Cisco_7200_Simulator

Dynagen:
http://dynagen.org

GUI for Dynagen and Dynamips. (Recommended for Windows users):
http://www.gns3.net

Dynamips Support Forum:
http://7200emu.hacki.at/index.php