Re: [dhcwg] DHCP and DHCPv6 options for LWM2M services

"Bernie Volz (volz)" <> Thu, 12 January 2017 14:08 UTC

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From: "Bernie Volz (volz)" <>
To: Srinivasa Rao Nalluri <>, "" <>
Thread-Topic: DHCP and DHCPv6 options for LWM2M services
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Date: Thu, 12 Jan 2017 14:08:10 +0000
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Cc: Amit Gupta X <>, Jan Melen <>, =?iso-8859-1?Q?Ari_Ker=E4nen?= <>, =?iso-8859-1?Q?Jaime_Jim=E9nez?= <>
Subject: Re: [dhcwg] DHCP and DHCPv6 options for LWM2M services
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A couple of (I think) additional comments on this draft:

1.       It be best to use DHCPv4 and DHCPv6 (and use DHCP for when you are specifically referring to both)? For example, it helps to be clear that an option is a v4 vs v6 option.

2.       For the DHCPv4 , you don't need the sequence number in the OPTION_LWM2M_SERVER_CERTIFICATE option and much of the text below. DHCPv4 already supports LONG options (more than 255 bytes of data) - see RFC 3396 - Encoding Long Options in the Dynamic Host Configuration Protocol (DHCPv4). You just need to say that this option uses this encoding.

   Maximum possible value of DHCP "option-len" is 255.  LWM2M-server-
   certificate MAY be of length more than 255.  To accommodate larger
   certificate, it SHOULD be possible to include multiple
   OPTION_LWM2M_SERVER_CERTIFICATE options in same DHCP message.  DHCP
   server SHOULD be capable of including multiple
   OPTION_LWM2M_SERVER_CERTIFICATE options in same message.
   Certificates larger than 255 byte SHOULD be fragmented and adjusted
   in minimum possible number of OPTION_LWM2M_SERVER_CERTIFICATE
   options.  Each OPTION_LWM2M_SERVER_CERTIFICATE option is tagged with
   a sequence number which can be used by DHCP client to reassemble
   received certificate

-          Bernie