Dynamips, Công cụ mô phỏng đồ Cisco thật nhất

[telecom1988]

1. Introduction
First of all, I want to say thank you to Opensource’s world and guys who are developing this great tool. A special thank is also sent to Mr.Tuyen, a counterpart of mine, who introduce me this interesting software.

For a long time, I didn’t write any tutorial related to techniques, but today I would like to introduce one thing that must be very interesting for students as well as new graduated engineers. That’s new tool for simulating Cisco products. This tool will helps students and engineers who want to practice or take Cisco certificates such as CCNA, CCNP, CCIP... easier by supporting real command sets.

I want to introduce you Dynamips Cisco Simulator , a new generation of simulation, which is being developed by OpenSource community. This is very far different from what ever you know from RouterSim, Boson or any exited simulators. The principle of old generation simulator, like RouterSim, is that it tries to simulate some of the commands or feature sets in router. In another works, these old tools use the software to simulate the software. But Dynamips is quite different. Instead of using software to simulate software, Dynamips is a software program which simulates hardware. That’s quite strange with us, right?. In fact, it’s not. If you know how VMware works, I think you will understand how Dynamips works. VMWare simulates the hardware infrastructure including CPU, RAM, I/O ports, NIC, etc...then we can install any software in that virtual machine. And Dynamips is the same. After establishing Cisco devices (in the newest version, Dynamips supports Cisco7200, Cisco 3600) we can load any router OS (IOS) into this virtual machine and.....run.
Obviously, with this kind of virtualization, there is no limit in feature sets. We can practice with any commands and feature sets that IOS have. It ranges from basic configuration, routing&switching to MPLS. Everything is in one simulators, that’s imaging. Remember, with old simulators we are supported a limited commands and feature sets. So thanks for the Opensource’s world. God helps you.

2. What’s Dynamips
Dynamips is a free program which aims to simulate some of Cisco devices such as Cisco 7200, Cisco 3600. In future, this simulator will virtualize Cisco Switches. Dynamips can run in different systems such as Linux, Windows with simple configuration. Ordinarily, Dynamips only support text command only, but recently some guys have coordinated in a SourceForce program to issue a GUI version in here.

Because it simulates real device so that it will take a lot of resource in your computer, especially memory and CPU. For example, I use my laptop with dual core 1,66Ghz; 512Mb to simulates maximum six (06) Cisco 7200. It’s recommend you use powerful PC (like me ) to run the simulator or you can use more than one PC to simulate multi routers and connect them by NIC card. I will show you how to connect multi PC to form a complex topology later.

As I mention above, in the newest version, Dynamips supports two main Cisco series: Cisco 7200 and Cisco 3600. It requires you little understand about these router’s infrastructure before setting up a virtual router. This information is not supported by the primary instruction of Dynamips (as you know, it not fully support because it’s free ), but I will give it to you in this tutorial.

3. A brief introduction about Cisco 7200
Cisco 7200 is a mid-range router platform, which is often used in core or distribution layer. The heart of Cisco7200 is CPU. You can freely choose a suitable CPU for this chassis, there are many CPU types that can be integrated in Cisco7200 chassis ranging from: NPE-100; NPE-175; NPE-200; NPE-400; G1; G2. But this simulator only supports the first four CPU.

Cisco 7200 chassis has 7 slots. The interface cards will be inserted into these slots. In the newest version Dynamips supports the following interface cards:
C7200-IO-FE (FastEthernet, slot 0 only)
PA-FE-TX (FastEthernet, slots 1 to 6)
PA-4T+ (Serial, 4 ports)
PA-8T (Serial, 8 ports)
PA-A1 (ATM)
POS (Packet over Sonet) card "PA-POS-OC3" (experimental, only works with recent IOS images)
In the real world, you have to compile those interface cards into Cisco 7200 chassis to have a complete router. For example: if you desire a Cisco7200 with 2 Ethernet and 3 serial you could configure as the sample below in a Cisco7200 chassis:
- use slot0 for C7200-IO-FE card
- use slot1 for PA-FE-TX card
- and slot2 for PA-4T+ card.
4. How to configure a virtual Cisco7200
OK, it’s time for us to focus on the main point of this tutorial. The following steps will help you to build a network with Dynamips.
Step 1: identify needed network topology.



Step 2: identify each router’s configuration (How many interfaces? What kind of interface (Ethernet, Serial, PoS)?
Step 3: choose appropriate cards
Step 4: read Dynamips Howto
Step 5: add all commands in one BAT file like this (this is the configuration file which relate to this topology above)



<run.bat>

start /BELOWNORMAL dynamips -i 1 -r 64 -t npe-100 -M std -X -p 0:C7200-IO-FE -p 1:pA-4T+ -s 1:0:udp:10001:127.0.0.1:10002 -s 1:1:udp:10005:127.0.0.1:10006 -s 0:0:udp:10062:127.0.0.1:10061 image\c7200-p-mz.121-27b.bin
start /BELOWNORMAL dynamips -i 2 -r 64 -t npe-175 -M std -X -p 0:C7200-IO-FE -p 1:pA-4T+ -s 1:0:udp:10010:127.0.0.1:10009 -s 1:1:udp:10002:127.0.0.1:10001 -s 0:0:udp:10126:127.0.0.1:10125 image\c7200-p-mz.121-27b.bin
start /BELOWNORMAL dynamips -i 3 -r 64 -t npe-100 -M std -X -p 0:C7200-IO-FE -p 1:pA-4T+ -s 1:0:udp:10006:127.0.0.1:10005 -s 1:1:udp:10009:127.0.0.1:10010 image\c7200-p-mz.121-27b.bin
start /BELOWNORMAL dynamips -i 4 -r 64 -t npe-100 -M std -X -p 0:C7200-IO-FE -p 1:pA-4T+ -s 0:0:udp:10061:127.0.0.1:10062 image\c7200-p-mz.121-27b.bin
start /BELOWNORMAL dynamips -i 5 -r 64 -t npe-100 -M std -X -p 0:C7200-IO-FE -p 1:pA-4T+ -s 0:0:udp:10125:127.0.0.1:10126 image\c7200-p-mz.121-27b.bin