User talk:ErikPeeters

Optipoint Automatic vlan Discovery as described on http://wiki.siemens-enterprise.com/index.php/VLAN_ID_Discovery_over_DHCP

Reading the article on automatic vlan discovery for Optipoint VoIP phones I see 2 things on which I question the necessity.

I'm using an ISC based DHCP server (on Infoblox appliance) that uses a configuration for vendor encapsulated options via an option space.

I configure option code 1 (tag 1) as type string and fill out the string Siemens. ISC translates this to 01 07 53 69 65 6D 65 6E 73 in staid of 01 0A 53 69 65 6D 65 6E 73 00 00 00

I do not understand why the 3 fill bytes are needed and why the length needs to be always 10. I could workaround the issue and fill out 53:69:65:6d:65:6e:73:00:00:00 as my value for tag 1 (which Infoblox will recognize as hex string and in the packet it will translate to what is expected according to the article.)

Although, it would be nicer and more readable if I could enter the word "Siemens". I believe to remember that this used to work (but given the article and the fact I can not get it to work with current Siemens customer, I start wondering and would like some confirmation.

Second thing which actually is of bigger concern is the 5 padding bytes in the end of the option: 00 00 00 00 00 FF

ISC does not add those, nor can I add them via an option code of option 43. ISC does start option 43 with the hex code for (2B) and the length of the complete option, therefore client can know the end. If the 5 padding options and closing with FF is really needed to make it work, it means I can not use an option space where I can put Siemens on a global config level for the vendor code filter and set vlan on range level. But I would need to calculate the full option 43 Hex string wherever I need to put a vlan and fill out option 43 in staid of using a "suboption 2".

A third thing is that I believe to have seen Optipoint config work with option code 2 configured with a length 2: 02 02 00 04 option 2 length 2 vlan 4

in staid of 02 04 00 00 00 04 option 2 length 4 vlan 4

I believe this has worked without both of these in earlier versions, but given that it does not work with this config at customer site, I start to doubt.

Unfortunately I do not have a Siemens phone to test this out myself.

Can anyone confirm that an option for Optipoint would work - without the 3 paddings behind Siemens - without the 5 paddings and FF at the end of option 43 - with a vlan of length 2