Build a Voice and Data Lab

Build a Packet Tracer office network with VLANs, DHCP, and IP phone calling.

Introduction

30 Second Summary

Office computers often share network equipment with desk phones. When every desk depends on the same network, one unclear connection can make a simple fault hard to trace.

In this project, you will build a two-desk office network in Cisco Packet Tracer. The finished lab keeps PC traffic separate from phone traffic while completing a call from extension 1001 to extension 1002.

What You'll Build

Your finished two-desk lab ends with the second phone ringing when you call extension 1002 from extension 1001.

By the end of this project, you'll have:

  • A working data network where both PCs receive addresses from the data VLAN through DHCP. You can prove the connection with successful ping replies.
  • A separate voice VLAN that gives both phones their own 192.168.20.x addresses automatically.
  • Registered extensions 1001 and 1002 through Cisco Unified CME. Calling one extension makes the other desk ring.
  • Secret Mission: Add a third desk with extension 1003 while keeping the original two desks working.

Are there any prerequisites?

Cisco Packet Tracer must already be installed. You also need access to a signed-in session.

Basic familiarity with the Cisco IOS CLI is helpful. The walkthrough explains each command.

Before We Start

Before you begin working in Cisco Packet Tracer, lock in what you are building and why separate voice and data networks matter.

Assemble and Validate the Topology

A correct configuration cannot rescue a cable connected to the wrong port. An unpowered phone creates the same dead end.

You will assemble the office in Cisco Packet Tracer. You will then prove the phones receive power and the router supports Cisco Unified CME before adding any configuration.

In this step, get ready to:
  • Place the six office devices in the Logical workspace.
  • Cable the router, switch, phones, and PCs through the intended ports.
  • Confirm phone power and router support for telephony configuration.
Place the office devices

A logical topology shows how network devices connect without recreating their physical room. This workspace gives you a clear view of both office desks.

  • Press Cmd+Space on macOS or the Windows key on Windows to open system search.
  • Type Cisco Packet Tracer and press Enter to open it.
  • Complete the sign-in prompt using your Packet Tracer account.
  • Select Logical in the top-left view controls.

You should now see an empty Logical workspace. The device palette sits below the workspace.

  • Select Network Devices in the bottom-left device palette.
  • Select the router subcategory icon.
  • Drag one Cisco 2811 router into the upper-left area of the workspace.
  • Select the switch subcategory icon.
  • Drag one Cisco Catalyst 3560-24PS switch beside the router.
  • Select End Devices in the bottom-left device palette.
  • Drag two Cisco IP Phone 7960 devices below the switch.
  • Drag two Packet Tracer PCs beside their matching phones.

You should see one router beside one switch. Below them you should see two phone-and-PC desk pairs.

Cable the two desks

The switch supplies Power over Ethernet to each phone. Each phone also provides a PC-facing port so one switch connection can serve an entire desk.

  • Select Connections using the lightning-bolt icon in the bottom toolbar.
  • Select the Copper Straight-Through cable for each link.
  • Connect router FastEthernet0/0 to switch FastEthernet0/1.
  • Connect switch FastEthernet0/2 to the left phone's Switch port.
  • Connect switch FastEthernet0/3 to the right phone's Switch port.
  • Connect the left phone's PC port to the left PC's FastEthernet0 port.
  • Connect the right phone's PC port to the right PC's FastEthernet0 port.
  • Hover over each cable endpoint to confirm the intended port labels.

Phone startup can take about a minute after the PoE link comes up. A dark display during those first moments is normal.

Once startup completes you should see both phone displays powered. The router link can remain red because its interface has not been enabled.

Why Use This Switch?

The Cisco Catalyst 3560-24PS supplies power through its Ethernet ports. This removes the need for separate simulated power adapters.

Each phone passes the PC's data through its PC-facing port. This layout lets one switch port carry the traffic for a complete desk.

Phone Still Dark?

Confirm that the switch model is Cisco Catalyst 3560-24PS. Check that each switch cable reaches the phone's Switch port.

Make sure the PC cable uses the phone's separate PC port. Help me diagnose an unpowered Packet Tracer IP phone.

Confirm power and telephony support

The physical topology is ready once both phones have power. A quick Cisco IOS check also confirms that this simulated router supports the telephony mode used later.

Before you check, do you expect the phone display and router prompt to prove that this lab is ready?

  • Click either phone in the Logical workspace.
  • Inspect its display for a powered screen.
  • Close the phone window.
  • Click the Cisco 2811 router.
  • Select the CLI tab.
  • Decline the initial setup dialog if the router presents one.
  • Press Enter to reveal the router prompt.
  • Enter telephony configuration mode by running these commands:
enable
configure terminal
telephony-service

What Does This Check Prove?

  • The enable command gives you access to privileged router commands.
  • The configure terminal command opens global configuration mode.
  • The telephony-service command tests whether the Cisco 2811 supports the required telephony configuration mode.

You should see Router(config-telephony)#. This confirms the router accepts telephony configuration mode.

You have entered only configuration mode. No telephony values have been added.

Prompt Did Not Change?

Confirm that the router model shown in the workspace is Cisco 2811. Enter each command on its own line so you can see the prompt change after every command.

If the CLI remains at the user prompt, enter enable before trying again. Help me reach telephony configuration mode.

  • Close the router window to return to the complete Logical workspace.

That is the physical foundation complete. Next up, you will bring the PC data network online.

Build the Data Network

Your two-desk topology is powered. Every link is in place.

In this step, you will build the data path in Cisco Packet Tracer with a data VLAN plus DHCP. Keeping phone services out of this configuration creates a focused test of what the data network can provide.

In this step, get ready to:
  • Build VLAN 10 from the switch access ports through the router gateway.
  • Serve automatic PC addresses from the DATA DHCP pool.
  • Prove PC connectivity before checking the phone displays.
Configure the switch data path

VLAN 10 separates PC traffic from the rest of the switch. An 802.1Q trunk carries that VLAN between the switch and router over one physical link.

  • Select the Cisco Catalyst 3560-24PS in the Logical workspace.
  • Select the CLI tab.
  • Create VLAN 10 with the DATA name by entering this command sequence:
enable
configure terminal
vlan 10
 name DATA
exit

What does this configuration do?

  • The first two commands enter privileged mode followed by global configuration mode.
  • The VLAN commands create VLAN 10 with the readable name DATA.
  • The final command returns the switch to global configuration mode.
  • Confirm the switch returns to global configuration mode without rejecting a command.

VLAN command rejected?

Check that you selected the switch CLI. Confirm that the prompt was in global configuration mode before entering the VLAN commands.

Help me correct my VLAN 10 switch configuration.

  • Configure FastEthernet0/1 as the router-facing trunk by entering:
interface FastEthernet0/1
 switchport mode trunk
exit

How does the trunk help?

FastEthernet0/1 connects to the router. Trunk mode allows tagged VLAN traffic to cross that connection.

  • Confirm the switch accepts the trunk command before returning to global configuration mode.

Trunk command rejected?

Confirm that the interface name is FastEthernet0/1. Check that you remained in global configuration mode after creating VLAN 10.

Help me troubleshoot the FastEthernet0/1 trunk.

  • Place the first phone-facing port in access VLAN 10 by entering:
interface FastEthernet0/2
 switchport mode access
 switchport access vlan 10
exit

What happens on FastEthernet0/2?

Access mode assigns untagged PC traffic from the first phone to VLAN 10. The phone passes that PC traffic through its PC-facing port.

  • Confirm the CLI returns to global configuration mode without rejecting the access-port commands.

First access port rejected?

Confirm that VLAN 10 exists. Check that the interface name matches FastEthernet0/2.

Help me fix the FastEthernet0/2 access configuration.

  • Place the second phone-facing port in access VLAN 10 by entering:
interface FastEthernet0/3
 switchport mode access
 switchport access vlan 10
exit
end

What completes the switch path?

FastEthernet0/3 gives the second PC the same VLAN 10 path. The final command leaves configuration mode after the switch data path is complete.

  • Confirm the CLI returns to privileged mode without rejecting a command.
  • Check that the links from FastEthernet0/2 and FastEthernet0/3 remain active in the Logical workspace.

Second access port rejected?

Confirm that you entered FastEthernet0/3. Compare its access commands with the accepted FastEthernet0/2 configuration.

Help me compare my two access-port configurations.

Configure the router gateway and DHCP scope

A router-on-a-stick design uses subinterfaces to route VLANs across one physical router port. The DATA subinterface becomes the PCs' gateway at 192.168.10.1/24.

Why router-on-a-stick?

A separate physical router interface for every VLAN would consume more ports. Subinterfaces let one trunk carry multiple VLAN gateways.

  • Select the Cisco 2811 router in the Logical workspace.
  • Select the CLI tab.
  • Enable FastEthernet0/0 without assigning a Layer 3 address by entering:
enable
configure terminal
interface FastEthernet0/0
 no ip address
 no shutdown
exit

What happens to the physical interface?

  • FastEthernet0/0 provides the physical connection to the switch.
  • The physical interface stays without an IP address because the subinterface holds the gateway address.
  • The interface is enabled so traffic can cross the link.
  • Watch the router-to-switch link in the Logical workspace.

You should see the link become active after the interface initializes.

Router link still inactive?

Confirm that the cable connects router FastEthernet0/0 to switch FastEthernet0/1. Check that the router accepted the interface enable command.

Help me diagnose my inactive router-to-switch link.

  • Create the VLAN 10 subinterface with its gateway address by entering:
interface FastEthernet0/0.10
 encapsulation dot1Q 10
 ip address 192.168.10.1 255.255.255.0
exit

What does the subinterface provide?

  • FastEthernet0/0.10 represents VLAN 10 on the router.
  • The encapsulation command associates tagged VLAN 10 traffic with this subinterface.
  • The address 192.168.10.1 becomes the default gateway for DATA clients.
  • Confirm the router accepts the subinterface commands before returning to global configuration mode.

Subinterface command rejected?

Confirm that you entered FastEthernet0/0.10. Check that VLAN 10 appears in the encapsulation command.

Help me correct my DATA subinterface.

  • Create the DATA DHCP scope by entering:
ip dhcp excluded-address 192.168.10.1 192.168.10.10
ip dhcp pool DATA
 network 192.168.10.0 255.255.255.0
 default-router 192.168.10.1
exit
end

How does the DATA scope work?

  • The excluded range reserves addresses 192.168.10.1 through 192.168.10.10.
  • The DATA pool serves addresses from the 192.168.10.0/24 network.
  • Each client receives 192.168.10.1 as its default gateway.
  • Confirm the router returns to privileged mode without rejecting the DHCP commands.

DHCP pool command rejected?

Confirm that the pool name is DATA. Check the network mask plus the default gateway against the subinterface configuration.

Help me troubleshoot my DATA DHCP pool.

✔️ Awesome, I've got everything!

Your switch now carries VLAN 10 to the router. Your router now supplies the DATA gateway plus DHCP service.

ⓧ I'd like to double check the full code

Compare your router configuration with this complete command sequence:

enable
configure terminal
interface FastEthernet0/0
 no ip address
 no shutdown
exit
interface FastEthernet0/0.10
 encapsulation dot1Q 10
 ip address 192.168.10.1 255.255.255.0
exit
ip dhcp excluded-address 192.168.10.1 192.168.10.10
ip dhcp pool DATA
 network 192.168.10.0 255.255.255.0
 default-router 192.168.10.1
exit
end

Router checkpoint

This configuration enables FastEthernet0/0. It creates the VLAN 10 gateway at 192.168.10.1. It also supplies the complete DATA DHCP scope.

Compare your switch configuration with this complete command sequence:

enable
configure terminal
vlan 10
 name DATA
exit
interface FastEthernet0/1
 switchport mode trunk
exit
interface FastEthernet0/2
 switchport mode access
 switchport access vlan 10
exit
interface FastEthernet0/3
 switchport mode access
 switchport access vlan 10
exit
end

Switch checkpoint

This configuration creates VLAN 10. It trunks FastEthernet0/1. It places both phone-facing access ports in the DATA VLAN.

Verify the data path

The network can now assign PC addresses automatically. A successful ping proves that the complete Layer 2 plus Layer 3 data path works.

  • Select the first PC in the Logical workspace.
  • Select the Desktop tab.
  • Open IP Configuration.
  • Select DHCP.

You should see DHCP request successful. The assigned IPv4 address should begin with 192.168.10..

  • Select the second PC in the Logical workspace.
  • Select the Desktop tab.
  • Open IP Configuration.
  • Select DHCP.

You should see another successful DHCP request. This PC should receive a different 192.168.10.x address.

  • Return to the first PC.
  • Select the Desktop tab.
  • Open Command Prompt.
  • Inspect the first PC's complete network settings by running:
ipconfig /all

What should you inspect?

The output lists the address supplied by DHCP. It also lists the PC's subnet mask plus default gateway.

  • Record the first PC's IPv4 address as first PC IPv4 address.
  • Return to the second PC.
  • Select the Desktop tab.
  • Open Command Prompt.
  • Inspect the second PC's complete network settings by running:
ipconfig /all

What confirms the second lease?

The second PC should have its own 192.168.10.x address. Its default gateway should be 192.168.10.1.

  • Record the second PC's IPv4 address as second PC IPv4 address.

Before you run the connectivity test, do you expect the two DHCP clients to reach each other through VLAN 10?

  • Return to the first PC's Command Prompt.
  • Test the path to the second PC by running:
ping [[SECOND_PC_IP="second PC IPv4 address"]]

What does this ping prove?

Successful replies prove that the first PC can reach the second PC through VLAN 10. They also prove that both phone-facing switch ports carry PC traffic.

You should see successful reply lines with no packet loss.

  • Return to the second PC's Command Prompt.
  • Test the reverse path to the first PC by running:
ping [[FIRST_PC_IP="first PC IPv4 address"]]

What does the reverse test add?

The reverse ping confirms two-way PC connectivity. Both desks now have a working DATA path.

You should see successful replies from the first PC.

Ping replies missing?

Confirm that both PCs received different 192.168.10.x addresses. Check that each PC lists 192.168.10.1 as its default gateway.

Help me trace my failed PC-to-PC ping.

  • Select either powered Cisco IP Phone 7960 in the Logical workspace.
  • Inspect the phone display for a usable extension.

The phone remains powered without a usable extension. Data connectivity alone has left the phone without a call-control identity.

Strong result. Your PCs now receive DATA addresses automatically and exchange traffic across the office network.

Your data path is working while the phone limitation is now visible. Next up, you will separate voice traffic and give the phones their own network services.

Separate Voice from Data

Your PCs already receive addresses from the data network. Their successful pings prove that the original side of your office network works.

The powered phones need their own voice VLAN instead of sharing the PC subnet. The existing 802.1Q trunk carries that voice traffic to the router, where a separate DHCP scope provides addressing plus TFTP discovery.

In this step, get ready to:
  • Prepare the phone-facing switch ports for voice traffic.
  • Provide a separate gateway and DHCP scope for the phones.
  • Compare the phone state with its new network lease.
Create the voice VLAN and prepare the phone ports

Each phone-facing port already carries PC traffic through access VLAN 10. You will add voice VLAN 20 plus QoS trust so the same physical port can identify phone traffic separately.

  • Switch back to the switch CLI from the previous step.
  • Apply only the new voice-specific settings by entering this configuration:
enable
configure terminal
vlan 20
 name VOICE
exit
mls qos
interface FastEthernet0/2
 switchport voice vlan 20
 mls qos trust cos
exit
interface FastEthernet0/3
 switchport voice vlan 20
 mls qos trust cos
exit
end

What does this switch configuration do?

  • The vlan 20 section creates the voice network named VOICE.
  • The mls qos command enables global quality-of-service processing on the switch.
  • The switchport voice vlan 20 command identifies tagged phone traffic as part of voice VLAN 20.
  • The mls qos trust cos command lets each port trust the phone's Layer 2 priority marking.

Before you check the first phone port, which VLAN numbers do you expect it to report for data traffic and voice traffic?

  • Check the first phone-facing port from the privileged prompt by running this command:
show interface fastethernet 0/2 switchport

What does this check prove?

The switchport output reports the access VLAN used by the attached PC. It also reports Voice VLAN: 20 for tagged phone traffic.

Good progress. FastEthernet0/2 now carries PC traffic in VLAN 10 plus phone traffic in VLAN 20 over one cable.

Voice VLAN 20 missing from the output?

Confirm that you configured FastEthernet0/2 on the switch. A setting applied to another interface will not change this port's output.

Check that the voice VLAN command uses VLAN 20. Also confirm that VLAN 20 is named VOICE.

Help me troubleshoot the voice VLAN settings on FastEthernet0/2 in Cisco Packet Tracer.

Provide voice addressing from the router

The router needs a gateway interface for voice VLAN 20. Its voice DHCP scope also supplies option 150, which points the phones to the router for TFTP discovery.

  • Switch back to the router CLI from the previous step.
  • Add the voice gateway plus its DHCP scope by entering this configuration:
enable
configure terminal
interface FastEthernet0/0.20
 encapsulation dot1Q 20
 ip address 192.168.20.1 255.255.255.0
exit
ip dhcp excluded-address 192.168.20.1 192.168.20.10
ip dhcp pool VOICE
 network 192.168.20.0 255.255.255.0
 default-router 192.168.20.1
 option 150 ip 192.168.20.1
exit
end

What does this router configuration do?

  • The FastEthernet0/0.20 subinterface terminates traffic tagged for VLAN 20.
  • The address 192.168.20.1 becomes the default gateway for the phones.
  • The exclusion reserves addresses 192.168.20.1 through 192.168.20.10.
  • The VOICE pool leases addresses from the 192.168.20.0/24 network.
  • The option 150 ip 192.168.20.1 line gives each phone the TFTP server address.

Phone renewal in Cisco Packet Tracer can take a short moment while each device requests fresh settings.

  • Wait for both phone displays to finish their network initialization.

Before you inspect the DHCP table, which address range do you expect the phones to use?

  • Display every active DHCP lease from the router's privileged prompt by running this command:
show ip dhcp binding

How do the bindings prove separation?

The table should contain the existing PC leases in the 192.168.10.x range. It should also contain phone leases in the 192.168.20.x range.

Those two ranges prove that one physical access switch is serving separate logical networks.

That is the voice addressing layer in place. Your PCs keep their original leases while the phones receive addresses from their own scope.

Still seeing only data leases?

Confirm that the router subinterface uses VLAN 20. Also check that the VOICE pool uses the 192.168.20.0 network.

Check both switch phone ports for the voice VLAN setting. A phone remains outside the voice scope when its switch port lacks that setting.

Help me find why my phones are not receiving 192.168.20.x DHCP leases.

Prove the separation and find the missing layer

The final comparison confirms that the PCs remain on the data network. It also reveals what network addressing provides for the phones.

  • Select the first PC in the Logical workspace.
  • Select the Desktop tab.
  • Open IP Configuration.
  • Confirm that the assigned address starts with 192.168.10.
  • Repeat the address check on the second PC.

Both PCs retain their data-VLAN addresses. The new voice configuration has preserved the working PC network.

Before you inspect a phone, do you think a voice address plus TFTP discovery is enough to create a dialable extension?

  • Select either phone in the Logical workspace.
  • Inspect its display for a usable extension.

The phone has network addressing, but its display still has no assigned extension. This shortfall is intentional.

What is still missing?

DHCP gives the phone an IP address plus a gateway. Option 150 gives it a TFTP destination.

Call control supplies the phone's dialable identity. The next layer must define extensions before the phones can place calls.

Your cumulative switch and router configurations should now match the voice-and-data checkpoint below.

✔️ Awesome, I've got everything!

The PCs use VLAN 10 while the phones use VLAN 20. Both DHCP address ranges now appear on the router.

ⓧ I'd like to double check the full code

These are the complete cumulative configurations for this checkpoint.

enable
configure terminal
vlan 10
 name DATA
exit
vlan 20
 name VOICE
exit
mls qos
interface FastEthernet0/1
 switchport mode trunk
exit
interface FastEthernet0/2
 switchport mode access
 switchport access vlan 10
 switchport voice vlan 20
 mls qos trust cos
exit
interface FastEthernet0/3
 switchport mode access
 switchport access vlan 10
 switchport voice vlan 20
 mls qos trust cos
exit
end
enable
configure terminal
interface FastEthernet0/0
 no ip address
 no shutdown
exit
interface FastEthernet0/0.10
 encapsulation dot1Q 10
 ip address 192.168.10.1 255.255.255.0
exit
interface FastEthernet0/0.20
 encapsulation dot1Q 20
 ip address 192.168.20.1 255.255.255.0
exit
ip dhcp excluded-address 192.168.10.1 192.168.10.10
ip dhcp excluded-address 192.168.20.1 192.168.20.10
ip dhcp pool DATA
 network 192.168.10.0 255.255.255.0
 default-router 192.168.10.1
exit
ip dhcp pool VOICE
 network 192.168.20.0 255.255.255.0
 default-router 192.168.20.1
 option 150 ip 192.168.20.1
exit
end

Your network now keeps phone traffic separate without disrupting either PC. Next, Cisco Unified CME gives each phone an extension so the two desks can finally call each other.

Register the Phones and Complete a Call

Your Cisco Packet Tracer office now separates PC traffic from phone traffic with a voice VLAN. Both phones can reach their TFTP address. Their empty extension displays show that addressing alone does not provide call control.

In this step, Cisco Unified CME gives each phone a directory number. The phones register as 1001 plus 1002 before you complete an internal call.

In this step, get ready to:
  • Create two CME directory numbers within a two-phone capacity.
  • Generate phone configuration files for automatic registration.
  • Prove that voice calls work alongside PC data traffic.
Define CME capacity plus extensions

A directory number gives a phone its callable extension. CME also needs limits that match the two phones plus the two directory numbers in this office.

  • Switch back to the router IOS CLI from earlier.
  • Enter privileged EXEC mode plus global configuration mode by running these commands:
enable
configure terminal

What do these commands do?

  • The enable command provides privileged access to the router.
  • The configure terminal command enters global configuration mode.
  • Add the two-phone CME limits plus both directory numbers by entering this configuration:
telephony-service
 max-ephones 2
 max-dn 2
exit
ephone-dn 1
 number 1001
exit
ephone-dn 2
 number 1002
exit

What does this configuration do?

  • The max-ephones 2 setting allows two phones to register with CME.
  • The max-dn 2 setting allows two directory numbers.
  • The first ephone-dn configuration creates extension 1001.
  • The second ephone-dn configuration creates extension 1002.
  • Confirm the router accepts each line without reporting a rejected command.
  • Confirm the final exit returns you to global configuration mode.

Did the router reject a command?

  • Confirm you are entering the commands on the Cisco 2811 router.
  • Confirm the router is in global configuration mode before entering telephony-service.
  • Recheck the spacing plus spelling of each command against the block above.

Help me diagnose a rejected Cisco Unified CME configuration command in Packet Tracer.

Generate phone registration files

The extensions now exist inside CME. Automatic assignment links those extensions to registering phones. The source address tells the phones where to establish their SCCP sessions.

  • Add automatic directory-number assignment plus the SCCP source address by entering this configuration:
telephony-service
 auto assign 1 to 2
 ip source-address 192.168.20.1 port 2000
 create cnf-files
end

How does registration work?

  • The auto assign 1 to 2 setting maps the two existing directory numbers to registering phones.
  • The ip source-address 192.168.20.1 port 2000 setting gives SCCP a reachable source address on the voice network.
  • The create cnf-files command generates the configuration files required by the phones.
  • The end command returns the router to privileged EXEC mode for verification.
  • Confirm the router accepts create cnf-files before returning to privileged EXEC mode.
  • Wait for both phone displays to refresh their registration state.

✔️ Awesome, I've got everything!

Great. Your router now contains the complete data, voice, DHCP, plus CME configuration. The switch configuration remains unchanged from the previous step.

ⓧ I'd like to double check the full code

Compare your cumulative router configuration with this reference:

enable
configure terminal
interface FastEthernet0/0
 no ip address
 no shutdown
exit
interface FastEthernet0/0.10
 encapsulation dot1Q 10
 ip address 192.168.10.1 255.255.255.0
exit
interface FastEthernet0/0.20
 encapsulation dot1Q 20
 ip address 192.168.20.1 255.255.255.0
exit
ip dhcp excluded-address 192.168.10.1 192.168.10.10
ip dhcp excluded-address 192.168.20.1 192.168.20.10
ip dhcp pool DATA
 network 192.168.10.0 255.255.255.0
 default-router 192.168.10.1
exit
ip dhcp pool VOICE
 network 192.168.20.0 255.255.255.0
 default-router 192.168.20.1
 option 150 ip 192.168.20.1
exit
telephony-service
 max-ephones 2
 max-dn 2
exit
ephone-dn 1
 number 1001
exit
ephone-dn 2
 number 1002
exit
telephony-service
 auto assign 1 to 2
 ip source-address 192.168.20.1 port 2000
 create cnf-files
end

Compare your unchanged switch configuration with this reference:

enable
configure terminal
vlan 10
 name DATA
exit
vlan 20
 name VOICE
exit
mls qos
interface FastEthernet0/1
 switchport mode trunk
exit
interface FastEthernet0/2
 switchport mode access
 switchport access vlan 10
 switchport voice vlan 20
 mls qos trust cos
exit
interface FastEthernet0/3
 switchport mode access
 switchport access vlan 10
 switchport voice vlan 20
 mls qos trust cos
exit
end

Before you check, how many registered phones do you expect the router to report?

  • Check registration from the router CLI by running this command:
show ephone registered

What should you see?

You should see two registered SCCP phones. Their assigned numbers should be 1001 plus 1002.

This output proves that both phones downloaded their generated configuration. It also proves that CME assigned both directory numbers.

  • Select the first phone in the Logical workspace.
  • Confirm its display shows either 1001 or 1002.
  • Select the second phone in the Logical workspace.
  • Confirm its display shows the remaining extension.

That is the registration gap closed. Each phone now has a callable identity.

Only one phone registered?

  • Confirm both phones still have DHCP addresses in the 192.168.20.x range.
  • Compare auto assign 1 to 2 with your router configuration.
  • Compare ip source-address 192.168.20.1 port 2000 with your router configuration.
  • Repeat the registration check after both phone displays finish refreshing.

Help me troubleshoot a Cisco IP phone that has a voice VLAN address but does not register with CME.

Prove converged connectivity

Registration proves that each phone can join CME. A completed call proves that the extensions can signal each other through the voice network.

Before you place the call, what should the receiving phone do after you enter its extension?

  • Select the phone displaying 1001.
  • Lift its handset.
  • Enter 1002.
  • Select the phone displaying 1002.
  • Lift its handset to answer the call.
  • Confirm both phone displays show the connected call.

You should see phone 1002 ring. After you answer, both displays show an active connection.

The call shares the same physical access links as the PCs. The final check confirms that adding call control preserved the data service.

  • Return to the first PC's Desktop tab from earlier.
  • Select Command Prompt.
  • Repeat the PC-to-PC ping test from Step 2 against the other PC's current 192.168.10.x address.
  • Confirm the replies are successful.

You should see successful replies from the other PC. Your office now carries a working phone call without sacrificing PC data traffic.

Call or data test failing?

  • Confirm both phones display their assigned extensions before placing the call.
  • Repeat the router registration check if the receiving phone does not ring.
  • Confirm both PCs still have addresses in the 192.168.10.x range if the data test fails.

Help me diagnose why my registered Packet Tracer phones cannot complete a call or why the PCs lost connectivity.

Secret mission

Add a Third Desk

Your two-desk office already handles data traffic and internal calls. Extend the same design to a third desk with extension 1003 without rebuilding the network.

Clean Up Your Resources

Clean Up Your Resources

Your entire lab runs inside Cisco Packet Tracer. It creates no cloud resources or ongoing costs.

Resources you used:

  • Your local three-desk Cisco Packet Tracer voice-and-data lab.

Keep everything running

Keep the lab if you want to demonstrate the three-phone call flow or extend it later. Saving preserves the complete topology plus its IOS configuration.

  • Select Save in Cisco Packet Tracer.
  • Use the save dialog to store the lab in a local folder you can find again.

Your Logical workspace should still show three connected desks after the save completes.

Pause - I'll come back to this later

Pausing closes the simulator session while preserving your work. The saved lab remains ready for another practice run.

  • Select Save in Cisco Packet Tracer.
  • Use the save dialog to store the lab in a local folder you can find again.
  • Close Cisco Packet Tracer after the save completes.

Cisco Packet Tracer is now closed. Your saved lab remains available locally at no ongoing cost.

Delete - I don't want to use this again

Deleting removes the saved lab from your computer. Cisco Packet Tracer itself remains installed.

  • Close Cisco Packet Tracer.
  • Open the local folder you selected when saving the lab.
  • Select the saved lab file for this project.
  • Delete the selected lab file using your operating system's file removal control.
  • Return to the same folder to confirm the lab file no longer appears.

Nice Work!

Nice Work!

You did it! You built a working three-desk converged network lab in Cisco Packet Tracer.

You've learned how to:

  • Build a powered office topology where each PC connects through an IP phone to a PoE switch. Separate PC traffic from phone traffic with DATA and VOICE VLANs. Carry both VLANs over 802.1Q trunking to router subinterfaces.
  • Supply each network from an independent DHCP scope. Guide the phones to the TFTP service with option 150.
  • Register extensions 1001 and 1002 with Cisco Unified CME. Complete an internal phone call while both PCs retain data connectivity.
  • Extend the office with a third desk in the Secret Mission. Register extension 1003 without rebuilding the original network.

Ready to quiz yourself?