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CX-3000 boots: what does it send exactly in DHCP Discover OPTION 60 as vendor-specific-information?

OlivierRime
Occasional Advisor

CX-3000 boots: what does it send exactly in DHCP Discover OPTION 60 as vendor-specific-information?

I have found various answers: "CPE-OCPHONE", "MS-UC-Client", "CX-3000" . But in order to properly configure the DHCP, I have to known exactly what to expect, test that value and be able to take a decision on it.

 

A wireshark trace done on a VVX-500 showed that the OPTION 60 in "DHCP Discover" was formatted as string containing exactly "Polycom-VVX500", but I don't have a trace for a CX-3000.

 

Thanks in advance!

Message 1 of 8
7 REPLIES 7
SteffenBaierUK
Polycom Employee & Community Manager

Re: CX-3000 boots: what does it send exactly in DHCP Discover OPTION 60 as vendor-specific-informati

Hello OlivierRime,

welcome back to the Polycom Community.

The community's VoIP FAQ contains this post here:

Jul 11, 2014 Question: Why can we not sign into LYNC via Pin & Extension?

Resolution: Please verify that the phone has the correct time and the Option 43 and Option 120 is setup in the DHCP scope as explained =>here <= or => here <= 

 

When the Phone boots to acquire the IP address is does not yet require to send the relevant string aka vendor class.

 

Only when the PIN & Extension is added and the phone attempts to authenticate then a new DHCP Discover is started and for all devices the Vendor Class is MS-UC-Client.

Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.

Best Regards

Steffen Baier

Polycom Global Services

----------------
The title Polycom Employee & Community Manager is a community setting and does not reflect my role. I am just a simple volunteer in the community like everybody else. All posts and words are my own & do not represent the views of Employer.

----------------

Notice: This community forum is not an official Poly support resource, thus responses from Poly employees, partners, and customers alike are best-effort in attempts to share learned knowledge. If you need immediate and/or official assistance please open a service ticket through your proper support channels.
Please also ensure you always check the VoIP , Video Endpoint , Skype for Business , PSTN or RPM FAQ's
Message 2 of 8
OlivierRime
Occasional Advisor

Re: CX-3000 boots: what does it send exactly in DHCP Discover OPTION 60 as vendor-specific-informati

Thanks for this answer. Looking through these posts, I did not find the level of detail which I needed, so I did the exercise in the lab and found this (but I don't have a CX-3000 so the question remains open for the CX-3000):

 

 

DHCP Discover in the default VLAN ( OPTION 60 for a CX-500: : length = 11 string contents:  CPE-OCPHONE   ----------->

                                                                    OPTION 60 for a VVX-500: length = 14 string contents:  Polycom-VVX500 ) 

                                                                 ( OPTION 55: Param request list, 1 byte per parameter requested )

                                                                 ( other OPTIONS...)

 

<------  DHCP Offer  ( gives an IP address to the phone in the default VLAN, may include OPTION 43 with

                                      suboption 10 to specify the voice VLAN to which the phone is expected to change)

 

If this DHCP Offer did not include OPTION 43 with sub-option 10, the phone remains in the default VLAN and confirms that IP address, then issues a DHCP Request with OPTION 55 to ask for the rest of the parameters it needs.

 

If this DHCP Offer did include OPTION 43 with sub-option 10, the phone releases the IP address in the default VLAN and places a new request in the voice VLAN. Sames contents as in the default VLAN:

 

DHCP Discover in the voice VLAN ( OPTION 60 for a CX-500: : length = 11 string contents:  CPE-OCPHONE   ----------->

                                                                    OPTION 60 for a VVX-500: length = 14 string contents:  Polycom-VVX500 ) 

                                                                 ( OPTION 55: Param request list, 1 byte per parameter requested )

                                                                 ( other OPTIONS...)

 

<------  DHCP Offer  ( gives an IP address to the phone in the voice VLAN, may include OPTION 43 with sub-options 1 to 5,
                                      OPTION 120, OPTION 160, etc. all that is required to register to Lync)

 

The phone may issue another DHCP Request with OPTION 55 to ask for the rest of the parameters it needs. 

 

From that point on it is quiet until someone actually wants to login to the phone with extension and PIN, for instance.

When the user logs in, the phone issues a DHCP Inform as follows:

 

DHCP Inform  ( OPTION 60 for both the CX-500 and VVX-500: string of length 12:  MS-UC-Client )    -----------> 

                          ( OPTION 55 requesting a repetition of the OPTIONS 43 and 120 in case these changed between the time

                             the phone booted and the user logs in)

The phone also issues a DNS query for the SRV record _sipinternaltls._tcp.<domain> , possibly for other SRV records.

 

<------ DHCP Ack  ( OPTION 120 with the registrar FQDN, OPTION 43 with sub-options 1, 2, 3, 4, 5 )

 

Now I only need the same for the CX-3000....

Message 3 of 8
OlivierRime
Occasional Advisor

Re: CX-3000 boots: what does it send exactly in DHCP Discover OPTION 60 as vendor-specific-informati

I should have mentionned that this case assumes that neither CDP nor LLDP are configured to put the phone in the voice VLAN.

Message 4 of 8
SteffenBaierUK
Polycom Employee & Community Manager

Re: CX-3000 boots: what does it send exactly in DHCP Discover OPTION 60 as vendor-specific-informati


@SteffenBaierUK wrote:

 

When the Phone boots to acquire the IP address is does not yet require to send the relevant string aka vendor class.

 

Only when the PIN & Extension is added and the phone attempts to authenticate then a new DHCP Discover is started and for all devices the Vendor Class is MS-UC-Client.


Hello OlivierRime,

my above original reply already contained the Vendor Class information you requested. The linke troubleshooting FAQ post also outlines this and shows Wireshark examples.

The community's VoIP FAQ contains this post here:

 

Jul 10, 2013 Question: How can I use VLAN's with Polycom phones?

Resolution: Please check => here <=

 

The above contains all details in regards of the VLAN


Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.

Best Regards

Steffen Baier

Polycom Global Services

----------------
The title Polycom Employee & Community Manager is a community setting and does not reflect my role. I am just a simple volunteer in the community like everybody else. All posts and words are my own & do not represent the views of Employer.

----------------

Notice: This community forum is not an official Poly support resource, thus responses from Poly employees, partners, and customers alike are best-effort in attempts to share learned knowledge. If you need immediate and/or official assistance please open a service ticket through your proper support channels.
Please also ensure you always check the VoIP , Video Endpoint , Skype for Business , PSTN or RPM FAQ's
Message 5 of 8
OlivierRime
Occasional Advisor

Re: CX-3000 boots: what does it send exactly in DHCP Discover OPTION 60 as vendor-specific-informati

There was an imprecision in my post of yesterday: in case of VVX phone (and if neither CDP nor LLDP are working):

 

The DHCP server must answer differently based on vendor specific options received in DHCP Discover:

 

- if in DHCP Discover OPTION 60 there is "CPE-OCPHONE", the DHCP Offer will indicate the voice VLAN in DHCP OPTION 43 suboption 10 with the VLAN coded as a 2 bytes number.

 

- if in DHCP Discover OPTION 60 there is "Polycom-VVX..." where ... is the last 3 digits of the VVX phone type, the DHCP Offer must pass the voice VLAN in DHCP OPTION 128 with the voice VLAN coded as string as follows: "VLAN-A=<value>;"

 

Which makes very interesting what OPTION 60 contains for the CX-3000...

 

Note that it remains possible that I entirely misunderstand the process, but up to now I have not found the definitive description valid for all types of Polycom phones which may connect to Lync.

Message 6 of 8
SteffenBaierUK
Polycom Employee & Community Manager

Re: CX-3000 boots: what does it send exactly in DHCP Discover OPTION 60 as vendor-specific-informati

Hello OlivierRime,

Polycom and other manufacturers produce these optimized for Microsoft® Lync® CX Phone devices after a reference design and the embedded OS running on the phones is provided, supported and maintained by our partner Microsoft®.

You therefore may want to reach out to the Microsoft® community and / or Microsoft® support directly instead as this is the most direct and efficient path.

Please try here as a support forum or the publicly available Microsoft Lync Phone Edition instructions.

 

All other Polycom VVX, SPIP and SSIP Phones utilize a different method which is well documented in the Admin Guide and within the community.

 

If you require more details you should consider contacting a Polycom Sales engineer.

 

Best Regards

Steffen Baier

----------------
The title Polycom Employee & Community Manager is a community setting and does not reflect my role. I am just a simple volunteer in the community like everybody else. All posts and words are my own & do not represent the views of Employer.

----------------

Notice: This community forum is not an official Poly support resource, thus responses from Poly employees, partners, and customers alike are best-effort in attempts to share learned knowledge. If you need immediate and/or official assistance please open a service ticket through your proper support channels.
Please also ensure you always check the VoIP , Video Endpoint , Skype for Business , PSTN or RPM FAQ's
Message 7 of 8
OlivierRime
Occasional Advisor

Re: CX-3000 boots: what does it send in DHCP Discover OPTION 60 as vendor-specific-information

Thank you Steffen, as I now had the chance to check this DHCP process in depth, I think it will benefit the community to list the outcome here. So whatever I previously wrote is superseded by the following. I now separate the CX phones DHCP boot process from the VX phones DCHP boot process. I also could test that the CX-3000 behaves like the CX-500, so this doubt is lifted.

 

CX phones DHCP process when LLDP is not configured on the LAN

 

  applies to CX-500, CX-600, CX-3000:

 

DHCP Discover in the default VLAN ----------->
                                  ( OPTION 60 for a CX-500, CX-600 or CX-3000: length = 11 string contents:  CPE-OCPHONE

                                  ( OPTION 55: Param request list, 1 byte per parameter requested )

                                  ( other OPTIONS...)

 

<------  DHCP Offer  ( gives an IP address to the phone in the default VLAN and if there is a voice VLAN,

                                      also includes OPTION 43 with suboption 10 to specify the voice VLAN to which the

                                      phone is expected to change: format  2B 04 0A 02 hh ll . 2B is header for OPTION 43, 04 is the

                                      length, 0A is sub-option 10 header, 02 is the length, hh ll is the VLAN

                                      number coded as high order byte first, low order byte second)

 

If this DHCP Offer did not include OPTION 43 with sub-option 10, the phone remains in the default VLAN and confirms that IP address, then issues a DHCP Request with OPTION 55 to ask for the rest of the parameters it needs.

 

If this DHCP Offer did include OPTION 43 with sub-option 10, the phone releases the IP address in the default VLAN and sends a new DHCP Discover in the voice VLAN. This DHCP Discover has the same contents as in the default VLAN:

 

DHCP Discover in the voice VLAN ----------->
                                 ( OPTION 60 for a CX-500, CX-600 or CX-3000: : length = 11 string contents:  CPE-OCPHONE

                                 ( OPTION 55: Param request list, 1 byte per parameter requested )

                                 ( other OPTIONS...)

 

<------  DHCP Offer  ( gives an IP address to the phone in the voice VLAN, may include OPTION 43 with sub-options 1 to 5,
                       OPTION 160, etc. but not yet OPTION 120)

 

The phone may issue another DHCP Request with OPTION 55 to ask for more parameters. 

 

From that point on it is quiet until someone actually wants to login to the phone with credentials or extension and PIN.

When the user logs in, the phone issues a DHCP Inform as follows:

 

DHCP Inform  ( OPTION 60: string of length 12:  MS-UC-Client )    -----------> 

             ( OPTION 55 requesting again OPTION 43 –in case something changed- and 120 –because now it needs

                somewhere to register to)

The phone also issues a DNS query for the SRV record _sipinternaltls._tcp.<domain> , possibly for other SRV records.

 

<------ DHCP Ack  ( OPTION 120 with the registrar FQDN, OPTION 43 with sub-options 1, 2, 3, 4, 5 )

 

---------------------------------------------------------------------------------------------------------------------------------------------------------------

 

VVX phones DHCP process when neither CDP nor LLDP is not configured on the LAN

 

DHCP Discover in the default VLAN ( OPTION 60 for a VVX-500: length = 14 string contents:  Polycom-VVX500  ----------->

                                  ( OPTION 55: Param request list, 1 byte per parameter requested )

                                  ( other OPTIONS...)

 

<------  DHCP Offer  ( gives an IP address to the phone in the default VLAN, may include OPTION 128 with

                       string contents “VLAN-A=<number>;” to specify the voice VLAN to which the phone is expected to change )

 

If this DHCP Offer did not include OPTION 128 with a voice VLAN, the phone remains in the default VLAN and confirms that IP address, then issues a DHCP Request with OPTION 55 to ask for the rest of the parameters it needs.

 

If this DHCP Offer did include OPTION 128, the phone releases the IP address in the default VLAN and places a new request in the voice VLAN. Sames contents as in the default VLAN:

 

DHCP Discover in the default VLAN ( OPTION 60 for a VVX-500: length = 14 string contents:  Polycom-VVX500  ----------->

                                  ( OPTION 55: Param request list, 1 byte per parameter requested )

                                  ( other OPTIONS...)

 

<------  DHCP Offer  ( gives an IP address to the phone in the voice VLAN, may include OPTION 43 with sub-options 1 to 5,
                       OPTION 160, etc. but not yet OPTION 120)

 

The phone may issue another DHCP Request with OPTION 55 to ask for the rest of the parameters it needs. 

 

From that point on it is quiet until someone actually wants to login to the phone with credentials or extension and PIN.

When the user logs in, the phone issues a DHCP Inform as follows:

 

DHCP Inform  ( OPTION 60 for both the CX-500 and VVX-500: string of length 12:  MS-UC-Client )    -----------> 

             ( OPTION 55 requesting again OPTION 43 –in case something changed- and 120 –because now it needs somewhere to register to)

The phone also issues a DNS query for the SRV record _sipinternaltls._tcp.<domain> , possibly for other SRV records.

 

<------ DHCP Ack  ( OPTION 120 with the registrar FQDN, OPTION 43 with sub-options 1, 2, 3, 4, 5 )

 

Message 8 of 8