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How IP phone understand the contact DHCP for IP address

Arjun Kamble
Level 1
Level 1

Hi All,

 

I hope you all are doing good, I have few Queries concern to IP phone

 

1) How IP phone understand the contact DHCP for IP address? If We have 3 DHCP server confirued in our Network, How IP phone will contact DHCP and which DHCP server for IP address?

 

2)  Why We give two Phone service URL in EM phone services feature? 2 URLs are as: HTTPS:// ; & HTTP://

 

3)  What is cause of Phone not getting registered with CUCM? Even there is no issue with Voice VLAN, Physical connectivity, hardware issue?

 

4)  How MTP or supplymentry service works on H323 and SIP network?

 

5) Steps of CUCM upgradation?

 

6) Steps of Firmware upgradation?

 

7) Steps of Unity intigration eith CUCM

 

 

 

Please send all above information to my email: arjun.kamble@rediffmail.com

 

 

Thank you,

Arjun Kamble

 

2 Accepted Solutions

Accepted Solutions

Dennis Fogler
Cisco Employee
Cisco Employee

In response to questions 1 & 3:

1) The Cisco IP Phone contacts the DHCP server accessible via the local LAN.  When the IP Phone boots, it will arp for an IP address and wait for a DHCP response.   If you have multiple DHCP servers, you can specify an IP Helper Address on the VLAN or switch sub-interface to direct the broadcast to the correct DHCP server.

2) Check to make sure option ip 150 points to the Communications Manager TFTP server.

Hope this helps.   -Dennis

View solution in original post

Deven Gandhi
Level 1
Level 1

During bootup process, phone will learn it's vlan via CDP and once it know which vlan it is part of, it will send out DHCP request.  Most of the time, you would add your voice DHCP scope on to local switch or voice-gateway.

Here is an example of what you would have on your local switch or gateway...

--- Exclude/Reserve first 10 IP from DHCP pool ---

ip dhcp excluded-address YYY.YYY.YYY.1 YYY.YYY.YYY.10

 

--- Configure voice DHCP device pool ---

ip dhcp pool phones

network YYY.YYY.YYY.0 255.255.255.0

domain-name YOURDOMAINNAME

dns-server XXX.XXX.XXX.XXX

default-router YYY.YYY.YYY.1

option 150 ip XXX.XXX.XXX.XXX

lease 3

Your switchport needs to include both access vlan and voice vlan as part of switchport config.

View solution in original post

3 Replies 3

Dennis Fogler
Cisco Employee
Cisco Employee

In response to questions 1 & 3:

1) The Cisco IP Phone contacts the DHCP server accessible via the local LAN.  When the IP Phone boots, it will arp for an IP address and wait for a DHCP response.   If you have multiple DHCP servers, you can specify an IP Helper Address on the VLAN or switch sub-interface to direct the broadcast to the correct DHCP server.

2) Check to make sure option ip 150 points to the Communications Manager TFTP server.

Hope this helps.   -Dennis

Jaime Valencia
Cisco Employee
Cisco Employee

http://docwiki.cisco.com/wiki/Unified_Communications_FAQ

A lot of what you're asking is simply a search away from you (CUCM upgrade for example on google, cisco.com or CSC), I cover a lot of CUCM upgrade questions, and plenty of it is within the product main documentation page

cisco.com -> Support -> All Products
Then either:
a) use the decision tree to look for the product
b) click the "Select a Product" drop down, scroll for the product, or type in the name of the product

5 and 7 you'll get the answer if you are a bit proactive and look at the CUCM and CUC documentation sites.

How to upgrade a FW, is explained in the FW release notes and README, you can get to all that by searching cisco.com or when you download it, the links are there.

About #3, it would be a matter of taking traces to confirm that indeed, there is no L2/L3 problem, and then see if the issue is actually on the phone, or CUCM, you can also look at the phone logs.

HTH

java

if this helps, please rate

Deven Gandhi
Level 1
Level 1

During bootup process, phone will learn it's vlan via CDP and once it know which vlan it is part of, it will send out DHCP request.  Most of the time, you would add your voice DHCP scope on to local switch or voice-gateway.

Here is an example of what you would have on your local switch or gateway...

--- Exclude/Reserve first 10 IP from DHCP pool ---

ip dhcp excluded-address YYY.YYY.YYY.1 YYY.YYY.YYY.10

 

--- Configure voice DHCP device pool ---

ip dhcp pool phones

network YYY.YYY.YYY.0 255.255.255.0

domain-name YOURDOMAINNAME

dns-server XXX.XXX.XXX.XXX

default-router YYY.YYY.YYY.1

option 150 ip XXX.XXX.XXX.XXX

lease 3

Your switchport needs to include both access vlan and voice vlan as part of switchport config.

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