188 Appendix B Troubleshooting WLAN IP Telephony installationsFormat of the IP Phone 2004 Terminal DHCP Encapsulated VendorSpecific optionThe following definition describes the Nortel IP Phone 2004 specific,Encapsulated Vendor Specific option. This option must be encapsulatedin a DHCP Vendor Specific option (Refer to RFC 1541 and RFC 1533)and returned by the DHCP server as part of each DHCP OFFER and ACKmessage for the IP Phone 2004 to accept these messages as valid. TheIP Phone 2004 pulls the relevant information out of this option and usesit to configure the primary and (optionally) secondary TPSs. Either thisencapsulated option or a similarly encoded site-specific option must bepresent. Configure the DHCP server to send one or the other—but notboth. WinNT implementations must use the Site Specific option. For moreinformation, see "DHCP support for handsets that emulate the IP Phone2004" (page 187).The format of the Encapsulated Vendor Specific option field is: Type,Length, Data.• Type (1 octet): 5 choices: 0x80, 0x90, 0x9d, 0xbf, 0xfb (128, 144, 157,191, 251)With the choice of five types, the IP Phone 2004 can operate inenvironments where the initial choice is already in use by a differentvendor. Select only one Type byte.• Length (1 octet): variable—depends on message content• Data (Length octets): ASCII-based—format Nortel-i2004-A,iii.jjj.kkk.lll:ppppp,aaa,rrr;iii.jjj.kkk.lll:pppp,aaa,rrr— Nortel-i2004-A uniquely identifies this as the Nortel option.Additionally, the -A signifies this version of this specification. Forexample, future enhancements could use -B.— ASCII (,)—separates the fields— ASCII (;)—separates the primary from secondary server info— ASCII (.)—signals the end of the structure— iii.jjj.kkk.lll:ppppp—identifies the IP:port for the server(ASCII-encoded decimal)— aaa—identifies the action for the server (ASCII-encoded decimal,range 0 to 255)— rrr—identifies the retry count for the server (ASCII-encoded decimal,range 0 to 255)Nortel Communication Server 1000WLAN IP Telephony Installation and CommissioningNN43001-504 01.02 StandardRelease 5.0 15 June 2007Copyright © 2004-2007, Nortel Networks.
