A P P E N D I X C - Sun Ray and Network Parameter Delivery (DHCP)

A P P E N D I X C

Sun Ray and Network Parameter Delivery (DHCP)

Sun Ray relies on DHCP to obtain network parameters and Sun Ray parameters. Network parameters include IP address, subnet mask, and router.

Sun Ray parameters enable Sun Ray devices to function normally in a Sun Ray environment.For Sun Ray DTUs to be able to discover the Sun Ray server on the network, they need to have at least the AuthSrvr parameter delivered through DHCP.

For a more comprehensive treatment of DHCP, see the Dynamic Host Configuration Protocol RFC at http://www.ietf.org/rfc/rfc2131.txt?number=2131.

For details on DHCP Options and BOOTP Vendor Extensions, see http://www.ietf.org/rfc/rfc2132.txt?number=2132

TABLE C-1 lists the Sun Ray parameter symbol values defined in the DHCP table. The remainder of this appendix describes the encapsulated options.

TABLE C-1 Sun Ray Parameter Symbol Values (as defined in the DHCP table)
Parameter Name	Vendor ID Code Type	Mandatory/ Optional	Comments
NewTFlags	Vendor=SUNW.NewT.SUNW, 34, NUMBER, 4,1	Optional
Intf	Vendor=SUNW.NewT.SUNW, 33, ASCII, 1,0	Optional	Interface used for Sun Ray service
NewTDispIndx	Vendor=SUNW.NewT.SUNW, 32, NUMBER, 4,1	Optional
FWSrvr	Vendor=SUNW.NewT.SUNW, 31, IP, 1,1	Optional	Firmware server IP address (needed for firmware upgrade)
LogAppl	Vendor=SUNW.NewT.SUNW, 29, NUMBER, 1,1	Optional	Log level for application
LogVid	Vendor=SUNW.NewT.SUNW, 28, NUMBER, 1,1	Optional	Log level for video
LogUSB	Vendor=SUNW.NewT.SUNW, 27, NUMBER, 1,1	Optional	Log level for USB
LogNet	Vendor=SUNW.NewT.SUNW, 26, NUMBER, 1,1	Optional	Log level for network
LogKern	Vendor=SUNW.NewT.SUNW, 25, NUMBER, 1,1	Optional	Log level for kernel
LogHost	Vendor=SUNW.NewT.SUNW, 24, IP, 1,1	Optional	Log level for host
NewTBW	Vendor=SUNW.NewT.SUNW, 30, NUMBER, 4,1	Optional	Limits bandwidth available for the Sun Ray
NewTVer	Vendor=SUNW.NewT.SUNW, 23, ASCII, 1,0	Optional	Specifies which firmware version to upgrade to.
AuthPort	Vendor=SUNW.NewT.SUNW, 22, NUMBER, 2,1	Optional	Sun Ray server port to connect to
AltAuth	Vendor=SUNW.NewT.SUNW, 35, IP, 1,0	Optional	Alternate set of Sun Ray server IP addresses
AuthSrvr	Vendor=SUNW.NewT.SUNW, 21, IP, 1,1	Mandatory	Sun Ray server IP address to connect to
BarrierLevel	Vendor=SUNW.NewT.SUNW, 36, NUMBER, 4,1	Optional	Barrier level for firmware download

Sun Ray parameters are encapsulated vendor-specific options; that is, the value for the standard DHCP vendor-specific information is an encapsulated set of options that only the vendor equipment--the Sun Ray server, in this case--knows how to interpret.

Encapsulated Options

For each parameter name, there is a vendor ID, an option code, an option type, and an indication as to whether the parameter is mandatory.

Encapsulated options are somewhat more complicated, as illustrated in the following DHCPINFORM response, or DHCPACK, which shows the taxonomy of the bytes in the vendor-specific information portion.

					2b 4a 17 1d 32 2e 30   .......: .+J..2.0

0140  5f 31 39 2e 63 2c 52 45  56 3d 32 30 30 32 2e 30   _19.c,RE V=2002.0

0150  39 2e 30 36 2e 31 35 2e  35 34 21 04 68 6d 65 30   9.06.15. 54!.hme0

0160  1f 04 81 92 3a 88 15 04  81 92 3a 88 1d 01 06 1c   ....:... ..:.....

0170  01 06 1b 01 06 1a 01 06  19 01 06 18 04 81 92 3a   ........ .......:

0180  88 16 02 1b 61

Note - In this description, hexadecimal values are preceded by 0x and followed by their decimal value, after an = sign, as in 0x2b=43.

The first byte is the option code.

The next byte represents the encapsulated option length, that is, the number of bytes that make up the option value.

The next one or more bytes make up the multi-byte option value.
The option value is followed by another encapsulated option code, and so on.

The example begins with 0x2b=43, the DHCP option for vendor-specific information. It has a length of 0x4a=74 bytes, which is the total number of bytes that follow. These bytes contain the encapsulated vendor options.

The remainder of the example represents the value of the vendor-specific information options. The first byte contains the first encapsulated option, whose value is 0x17=23, and the NewTVer option, whose value type is ASCII. The next byte is 0x1d=29, which is the length of the NewTVer string. These options are followed by 29 bytes that represent the string itself.

The ASCII interpretation at the right of the DHCPACK, is
2.0_19.c,REV=2002.09.06.15.54. This is the end of the first encapsulated option. The next byte is the beginning of the next option, Intf, represented by 0x21=33. The next byte, the length, is 0x04=4, and the next four bytes are the ASCII value hme0. That's the end of the second encapsulated option.

The next byte is 0x1f=31, which represents the FWSrvr parameter, whose function is to indicate the IP address of the firmware TFTP server. The next byte is the length, 4, which is always be true for an IP address. The hexadecimal value is
0x81 0x92 0x3a 0x88, which corresponds to the IP address 129.146.58.136.