dhcp ip settings 2

[edex]

The main problem I got at the min is trying to pass the correct VLAN id to the phone via DHCP

I currently have a mini testing environment setup with one of the phones and a laptop. I have them both running through a Cisco switch on a trunked port


Both do get IP addresses from the DHCP server, but both on the same VLAN. If I manually set the VLAN id on the phone it does get the correct IP address and all is well. However if I try to set it through the DHCP server using Option 43 the phone seems to completely ignore it. Even if I follow the example in the documentation on setting the SW server, this does not work either


I’m thinking that either I’m not setting it correctly or there is something else wrong and was wondering if you could help

 

[ADB100]

VLAN discovery via DHCP option 43 is only available in the latest (or at least the last couple of versions). In vendor option 43 you need to specify Tag 05, followed by the length of the VLAN ID, followed by the VLAN in HEX. This is in addition to the Vendor String (Ericsson IP-Phone) and the 01 Tag to define the Webserver.
For example say the Voice VLAN is 100 you would add to the end of your DHCP Option 43:

05 03 31 30 30

05 being the Tag to indicate that a VLAN ID will follow, 03 indicating the length, then 31 for 01, 30 for 0 and 30 for 0.

Lets say your Webserver is 172.20.165.1 and your Voice VLAN is 100, then the Option 43 HEX entry in the data VLAN (access vlan or untagged VLAN depending on your switch vendor) would look like:

11 45 72 69 63 73 73 6F 6E 20 49 50 2D 50 68 6F 6E 65 01 0C 31 37 32 2E 32 30 2E 31 36 35 2E 31 05 03 31 30 30

HTH

Andy

 

[ADB100]

I meant to say the latest firmware......

Andy

 

[aastratech]

On the phone configuration file modify to suit the network above use these settings:

[ L2QS]
MIIport=6,100 ---prio =6 ,VID(100) This does not matter as you will take the VID from DHCP Offer [option43]
PCport=4,30 --- prio =4 ,VID(30) or whatever has been assigned for DATA VLAN for the PC traffic,
LANport=1,1 --- MAC based VLAN/802.1Q based VLAN , untagged/unmodified PC originating traffic

both vid 100 and 30 to be visible towards the network.

in alex look up
INSTALLATION INSTRUCTIONS 1531-DBC 425 01 Uen F
explains all you need.

 

[ADB100]

The better option is to use DHCP Option 43 since the phone requires a soft reset after it has read the config file. This is due to a'bug' whereby the phone doesn't release and renew the DHCP IP address from the access VLAN before starting to 'speak' with 802.1q tags (Voice VLAN).

If you have older firmware then the VLAN discovery via DHCP might not be available and the only option is via the config file.

This is all documented in ALEX.

Andy

 

[edex]

I have gone through the bits and pieces of setting up IIS and the DNS records

However, I’ve noticed now that both phones (IP 4422 and 4425 phones) have issues with getting addresses from the DHCP server. If I try to set the IP address manually, it displays “Error! Network interface not started, rebooting” and then….reboots and goes round in this loop



Have I broken them?

 

[VinceWhirlwind]

Having the same problem - Cisco PoE switches, Ericsson 4422 IP phones.

Nobody seems too sure about the precise VLAN and/or DHCP configuration which Ericsson provides for inter-operability with Cisco switches.

Configured manually, the phones operate perfectly, but left to DHCP they behave unpredictably and almost never succeed in getting a usable DHCP response.

At times they ignore DHCP offers; other times they seem to request an IP address in a completely irrelevant VLAN - mostly they allow the PC to work fine through them on the native VLAN, though.
At all times, plugging my laptop into the same wall port gets a successful DHCP negotiation.

Any ideas?

 

[LeeMason]

ADB100 is broadly correct with the option 43 string. However you need to add a couple of other tags on the end.

Quote: "Lets say your Webserver is 172.20.165.1 and your Voice VLAN is 100, then the Option 43 HEX entry in the data VLAN (access vlan or untagged VLAN depending on your switch vendor) would look like:

11 45 72 69 63 73 73 6F 6E 20 49 50 2D 50 68 6F 6E 65 01 0C 31 37 32 2E 32 30 2E 31 36 35 2E 31 05 03 31 30 30"

To the end of this add "06 03 31 30 30 07 03 31 30 30". This is because tag ID 5, 6, & 7 are all used for the voice VLAN ID. In addition this must be provided by DHCP servers in your default data VLAN as well as your voice VLAN.


Lee Mason
Optimal Projects Ltd

 

[ADB100]

Lee

From what you have stated the IP Phone will do this:

At Hard-boot it will not use any 802.1q Tags and lease an IP address from the DHCP server in the Access or Native VLAN. It will receive the DHCP offer along with the Option 43 information. It will then request the Configuration File from the Software Server. After the Configuration file has been received or it has timed out it will release the IP address and soft-reset. It will then attempt to lease an IP address using the 1st VLAN tag it received via Tag 05 (100), if that fails it will attempt the 2nd VLAN (Tag 06) and if that fails it will try the 3rd Tag. If that all fails it starts again.
However you have simply repeated the same VLAN tag in each Tag - 05 is 100, 06 is 100 and 07 is 100. This is not the way Ericsson intended this to work. The idea is it has a list of different VLAN tags to use - i.e. the 1st VLAN will be 100, the 2nd 101 and the 3rd 102. The end of the Hex string will look like this:

05 03 31 30 30 06 03 31 30 31 07 03 31 30 32

This does represent a bad design however since it is better to restrict each access switch to having a Single Data VLAN and a Single Voice VLAN. There should be no reason for the IP Phone to need to try multiple Voice VLANs.

Another thing that throws a new twist on this is DNS SVR record support and Vendor Class Identifiers that the latest firmware for the Version 2 handsets can use..... Much better and cleaner in my opinion and results in a much less complicated Option 43 string ;o)


Andy

 

[ADB100]

Another thing......... If you are using IIS (2000, XP or 2003) as the webserver be aware that by default they don't allow files with a '.dat' extension to be accessed and this is what Ericsson IP Phone firmware files use by default....

There are solutions to this though but these involve changing the configuration of IIS. Google it or look on MS's website.

In my experience DHCP works EVERY TIME as long as you configure it correctly. The ALEX documentation details all this really really well.

HTH

Andy