Time Protocol Servers and Time Offset options for DHCPv6 Ralph - - PowerPoint PPT Presentation

Time Protocol Servers and Time Offset options for DHCPv6

Ralph Droms

2005/11/08 dhc WG, IETF 64 2

Background

• Both options based on DHCPv4 options

(RFC 2132):

– Time Server Option (option code 4): “a list of RFC 868 time servers” – Time Offset (option code 2): “offset of the client's subnet in seconds from Coordinated Universal Time (UTC)”

• Both requested by CableLabs for DOCSIS

3.0 specification

2005/11/08 dhc WG, IETF 64 3

Time Servers option

• Returns list of available RFC 868 Time

Protocol servers to client

– Listed in preference order – Must be unicast or anycast

• Format:

1 2 2 3 0 1 2 2 3 3 4 5 5 6 6 7 8 8 9 9 0 1 1 2 2 3 4 4 5 5 6 7 7 8 8 9 0 0 1 1 2 3 3 4 4 5 6 6 7 7 8 9 9 0 0 1 +- +-+-+

• +-+-

+-+-+

• +-+-

+-+-+

• +-+-

+-+-+

• +-+-

+-+-+

• +-+-

+-+-+

• +-+-

+-+-+

• +-+-

+-+-+

• +-+-

+-+-+

• +-+-

+-+-+

• +-+-

+-+-+

• +

| | O OPTI TION_ N_RFC FC868 68_SE SERVE VER | 1 16 * * nu numbe ber-o

• of-s
• serv

rvers rs | | +- +-+-+

• +-+-

+-+-+

• +-+-

+-+-+

• +-+-

+-+-+

• +-+-

+-+-+

• +-+-

+-+-+

• +-+-

+-+-+

• +-+-

+-+-+

• +-+-

+-+-+

• +-+-

+-+-+

• +-+-

+-+-+

• +

| | se serve ver-a

• addr

dress ss1 | | . . .

Time Offset option

• Specifies the offset in seconds from

Coordinated Universal Time (UTC) that the client should use to determine its local time

– 32 bit signed integer for positive and negative

• ffset

– assumes DHCP server has knowledge of client

• ffset or location

Time Offset option Format

• Format:

0 1 2 3

0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | OPTION_TIME_OFFSET | 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | time_offset | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+