User manual

178 Troubleshooting WLAN IP Telephony installations
DHCP options
This section provides the IEEE definitions of the DHCP options. The term
SHOULD, as used in this section, is to be interpreted as described in
[RFC2119].
DHCP option 1: Subnet Mask. Length: 6 bytes
This option specifies the client’s subnet mask. If both the Subnet Mask and the router option are
specified in a DHCP reply, this option MUST be first.
00 01 02 03 04 05 06 07
Code
08 09 10 11 12 13 14 15
Length
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Mask
Code. 8 bits. Always set to 1.
Length. 8 bits. Always set to 4.
Mask. 32 bits. Subnet mask of the client.
RFCs: [RFC 2132] DHCP Options.
Updated by: RFC 3942.
DHCP option 3: Length: 6+ bytes This option specifies a list of 32 bit IP addresses for routers on
the client’s subnet. The routers SHOULD be listed in order of preference.
00 01 02 03 04 05 06 07
Code
08 09 10 11 12 13 14 15
Length
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
IP address
Code. 8 bits. Always set to 3.
Length. 8 bits. 4+ in multiples of 4.
IP address. 32 bits. One or more IPv4 addresses.
RFCs: [RFC 2132] DHCP Options.
Updated by: RFC 3942.
DHCP option 6: 6+ bytes This option specifies a list of DNS servers available to the client. The
servers SHOULD be listed in order of preference.
00 01 02 03 04 05 06 07
Code
08 09 10 11 12 13 14 15
Length
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
IP address
Code. 8 bits. Always set to 6.
Length. 8 bits. 4+ in multiples of 4.
IP address. 32 bits. One or more IPv4 addresses.
RFCs: [RFC 2132] DHCP Options.
DHCP option 7: 6+ bytes This option specifies a list of MIT-LCS UDP servers available to the
client. The servers SHOULD be listed in order of preference.
00 01 02 03 04 05 06 07
Code
08 09 10 11 12 13 14 15
Length
Nortel Communication Server 1000
WLAN IP Telephony Installation and Commissioning
NN43001-504 03.04 Standard
23 September 2008
Copyright © 2004–2008 Nortel Networks
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