01-29-2018 12:29 PM - edited 03-17-2019 12:04 PM
I have a CP-8851 phone.
An ethernet cable goes from the wall jack to the Ethernet Port and a cable goes from the PC Port to my PC. The PC is configured to have its IP address assigned via DHCP. DHCP is enabled on the phone.
What I would like to do is to configure a second PC by adding an unmanaged switch. I'm not sure if this is feasible.
When I put the switch between the wall and phone, the phone would not power-up.
When I put the switch off the PC port and connected my two computers to the switch. The one obtaining the IP address automatically still worked. The newly added PC would not obtain an IP. If I configured it using a static IP both PCs work.
I'm wondering if I can use it the way I am and have both PCs obtain the address via DHCP, if the way it is currently working might be short-lived until a DHCP address renewal request is made, or if the only real way is to configure them both statically.
Thank you,
- Nick
01-29-2018 01:17 PM
Hi Nick,
I have two of my PCs and a Cisco phone connected to one port that same way you have done the cabling. So cabling is correct. You should see 4 mac address like this.
sh mac address-table int g3/0/40
Mac Address Table
-------------------------------------------
Vlan Mac Address Type Ports
---- ----------- -------- -----
200 00f8.2c06.8827 DYNAMIC Gi3/0/40
200 509a.4c5a.5079 DYNAMIC Gi3/0/40
200 6400.6a5f.479a DYNAMIC Gi3/0/40
3000 00f8.2c06.8828 DYNAMIC Gi3/0/40
Total Mac Addresses for this criterion: 4
Also in the port configuration need to look like:
switchport access vlan 200
switchport mode access
switchport voice vlan 3000
did you try unplugging network cable from the computer that works with dhcp and used that cable into other computer? If that works, there is no issue with DHCP.
01-29-2018 01:26 PM
Hello,
Thank you for the response. Where would I see the Mac Address table and port configuration? Also, what is it telling me?
I have not tried swapping the cables. That would indicate?
[wall] --- [phone]----[switch via uplink port 5]--[(C#1-dynamic IP assignment on Port 3) & (C#2 static IP assignment on Port 4)]
I would be switching the cables on Port 3 and Port 4 to different computers. Is that correct?
01-29-2018 01:36 PM
01-29-2018 01:40 PM
01-29-2018 01:48 PM
01-29-2018 02:06 PM
Nick,
Cisco phone has an un-managed workgroup switch inside it with two ports. One port plugs into the data jack and other one plugs in to the PC. When you connect another unmanaged switch to the PC port it is like cascading workgroup switches. So the real managed Cisco switch will see all the mac address connected to that port.
01-30-2018 07:22 AM
01-30-2018 08:03 AM
01-31-2018 11:04 AM
did you get this resolved?
01-31-2018 12:55 PM
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