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	GNS3 Makes it Easy to Set Up a Home Lab October 15th, 2008 Ken Jaffe As an Instructor I am asked consistently about the best place to find used Cisco Hardware to set up a home lab.  Over the years many people have made suggestions such as eBay or Craig's list but recently I discovered GNS3, a Graphical Network Simulator (GNS).  GNS3 is a Network Emulation environment that integrates:  Dynamips, the core program that allows Cisco IOS emulation. Dynagen, a text-based front-end for Dynamips. Pemu, a Cisco PIX firewall emulator based on Qemu.

What makes this product so unique is it's ability to integrate all three and create an environment with Routers, Switches, Firewalls, WANs, and many other products.  You can create literally dozens of devices with a simple drag and drop.  Although it is a complex tool, their website www.GNS3.net has many video tutorials and detailed explanations on how to create many of the environments one would hope to emulate.  The one drawback to the software is that you must provide your own version of IOS software.  But with many old versions floating around it shouldn't be too difficult to find one lying around.

As a voice instructor I was curious if I could create a simple Voice network so I designed a simple lab environment and set out to create a totally virtual voice lab.

Diagram:

Topology:

Hardware:

I used a Windows based PC with a 1.5 GHz processor and 1.25 MB of memory running Windows XP Professional just to prove it didn’t require a powerful system. This is not recommended for an actual lab configuration

Software:

Windows XP Professional
GNS (GNS3-0.5-win32-all-in-one.exe)
TFTP32
Cisco Router IOS (c3725-ipvoice_ivs-mz.124-15.T7.bin)
and a graphical interface for CME (cme-gui-4.1.0.2.tar)
Cisco IP communicator (cipc-Admin-fmr.2-1-4.zip)
VTGO-PC Lite (vtgo-pc-lite.zip)
X-Lite (X-Lite_Win32_1011s_41150.exe)
Express Talk (talksetup.exe)

Steps:

1. Install GNS3, TFTP server and  Softphones (I choose 4 just to try both SCCP and SIP)

2. Configure MS-Loopbacks in Windows XP.

3. Start GNS3
    a. Add IOS image (Edit, IOS images and hypervisors)
    b. Drag nodes to workspace.
    c. Configure clouds for each branch (nio_gen_eth will be added for each MS-Loopback).
    d. Configure routers (add a Wic for the serial connection).
    e. Run Idle PC (I pegged 100% utilization immediately until I ran Idle PC, not a big surprise!).
    f. Configure switches (create connections to tie the MS-Loopback interfaces to the routers.

4. Start the routers and console in (there’s a Telnet icon).
    a. Optionally, copy the gui to flash (archive tar /xtract tftp://ip_addr/cme-gui-4.1.0.2.tar flash).
    b. Configure the routers (the following is part of my configuration)

! For SIP softphone
voice service voip 
 sip
  registrar server expires max 36000 min 600
!
voice class codec 1
 codec preference 1 g729r8
 codec preference 2 g711ulaw
 codec preference 3 g711alaw
!
voice register global
 mode cme
 source-address 6.6.6.5 port 2000
 max-dn 5
 max-pool 5
 timezone 13
 time-format 24
 hold-alert
 tftp-path flash:
 create profile sync 0001312594045447
!
voice register dn  1
 number 2001
 call-forward b2bua noan 2002 timeout 10
 name Ken
 label Kens Phone - 2001
!
voice register pool  1
 id mac 0000.0000.0001
 number 1 dn 1
 dtmf-relay rtp-nte sip-notify
 voice-class codec 1
 username 2001 password cisco
! To branch switch
interface FastEthernet0/0
 ip address 6.6.6.5 255.255.255.0
 duplex auto
 speed auto
! To other branch thru WAN
interface Serial0/0
 ip address 4.4.4.1 255.255.255.252
 clock rate 2000000
!
ip http server
! Dial peer for other branch phones
dial-peer voice 3000 voip
 destination-pattern 3...
 session target ipv4:4.4.4.2
!
telephony-service
 max-ephones 5
 max-dn 10
 ip source-address 6.6.6.5 port 2000
 time-zone 13
 max-conferences 8 gain -6
 web admin system name ken password cisco
 dn-webedit 
 transfer-system full-consult
 create cnf-files version-stamp Jan 01 2002 00:00:00
! SCCP softphone
ephone-dn  1
 number 2002
 label Kens Phone - 2002
! IP Blue needed a hard MAC address, Cisco IPC used a soft MAC address
ephone  1
 mac-address 0200.4C4F.4F50
 type CIPC
 button  1:1

    c. Save the configuration (not only do a copy running-config startup-config, but also use the Extract all startup-configs button).
    d. Now right-click on the routers and select Startup-config. Type in the path you used in the previous step to save configurations. (This will allow you to have GNS3 startup with configured routers.

5. Save the project (File, Save As).

Testing:

I set up 2 softphones for each branch, one SCCP (Cisco IPC and VTGO-PC Lite) and one SIP (Express Talk and X-Lite).

Cisco IP communicator – In preferences, soft-configure a MAC address (matching my Ephone configuration) and specified the TFTP address as the CME router.

VTGO-PC Lite – In settings, on the Network tab, configure a TFTP and CallManager address as the CME router and chose the MAC address and MS-Loopback network interface for the branch.

Express Talk – In options, on the Line tab, configure a SIP proxy as the CME router, SIP number as the directory extension (example, 3001), and a password (this must match the voice register pool configuration).

X-Lite - In SIP Accounts, configure a Domain as the CME router, User name and Authorization user name as the directory extension (example, 3001), and a password (this must match the voice register pool configuration).

I placed calls between the SIP and SCCP phones in the branch, and between SCCP phones in each of the branches using the H.323 gateway over the WAN.

Conclusion:

Pretty slick! Time involved, a couple hours. Expense, none! Frustration, very minimal! Other configurations to test – bring up my VMWare version of Unified Communications Manager 6 and Unity (that might involve using my “real” PC). Cheers!