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Bharat Joshi ( bharat_joshi@infosys ) Pavan Kurapati ( pavan_kurapati@infosys )

Bharat Joshi ( bharat_joshi@infosys.com ) Pavan Kurapati ( pavan_kurapati@infosys.com ) Infosys Technologies Ltd. Extension of DHCP LEASEQUERY in Bridging/Switching networks draft-joshi-dhc-lease-query-ext-02.txt DHC Working Group. STB. RG. STB. RG. RFC 4388 for Layer 3 Access Network.

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Bharat Joshi ( bharat_joshi@infosys ) Pavan Kurapati ( pavan_kurapati@infosys )

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  1. Bharat Joshi ( bharat_joshi@infosys.com ) Pavan Kurapati ( pavan_kurapati@infosys.com ) Infosys Technologies Ltd. Extension of DHCP LEASEQUERY in Bridging/Switching networks draft-joshi-dhc-lease-query-ext-02.txtDHC Working Group

  2. STB RG STB RG RFC 4388 for Layer 3 Access Network ACCESS CONCENTRATOR IP DSLAM /BRAS Local Loop DHCP Server Service Provider’s IP Network PC • Layer 3 Relay Agent • Add option 82 and “giaddr” • Extract information like MAC/IP/Lease time • Forwards DHCP reply based on option 82 • Extracted information can be used to: PC • Avoid MAC/IP Spoofing • Enhance Security by avoiding ARP generation • Generates DHCP Lease Query

  3. STB STB RG RG Extension of RFC 4388 to Layer 2 Access Networks DHCP Server Local Loop L3 Relay Agent Ethernet Aggregation Switch Service Provider’s IP Network Access Concentrator L2 Relay Agent • Add “giaddr” Local Loop • Forwards reply based on “giaddr” [Destination IP in DHCP reply] • Adds option 82 • Extracts information like MAC/IP/Lease time • Forwards reply based on option 82 • Extracted information can be used to: • Avoid MAC/IP Spoofing • Avoid Unknown MAC Flooding • Generates Lease Query

  4. Changes from 00 to 02 • New option for ‘Access Concentrator’ hardware address. • Added text for: • Layer 3 Relay Agent MUST NOT add option 82 to DHCPLEASEQUERY messages. • DHCP server MUST add the new option only in the reply of DHCPLEASEQUERY messages. • Handling multiple responses received for a DHCPLEASEQUERY message • If a Layer 2 Relay Agent can use its management IP address to talk to DHCP server than that should be preferred. • Added authentication details of DHCP LEASEQUERY messages as per RFC 3118 in security section. • Removed the restriction of mandating the insertion of new option at the end • Some minor comments and grammatical issues.

  5. Next Step • PoC implementation is doneand verified. • More review in WG mailing list. • Working group item?

  6. Stefaan De Cnodder Alcatel Pavan Kurapati Infosys Technologies Ltd. Unicast Address Sub-Option draft-decnodder-dhc-rai-unicast-01.txtDHC Working Group

  7. Need for unicast-address sub-option • DHCP replies are broadcast/flooded to L2 RA under below conditions : • If client sets Broadcast flag in DHCP requests • If L2 RA does MAC translation, Ethernet aggregation devices does not learn client’s MAC address. Hence even if broadcast flag is not set, replies are flooded to all the L2 RAs. • Flooding need to be avoided between L2 RA and L3 RA

  8. New sub-option in Option-82 • New sub-option called ‘unicast-address’ is defined for Relay agent option. • L2 RA fills unicast-address sub-option with: • ‘chaddr’ if L2 RA is acting as a bridge without MAC translation • The hardware address which is used for translation (eg, ACs MAC address) if L2 RA does MAC translation. .

  9. Processing of new sub-option • DHCP server MUST echo this sub-option as it is in option-82 • L3 RA should look for this new sub-option and if present use this MAC address to forward the DHCP messages irrespective of the broadcast flag. • L2 RA should respect the broadcast flag and should change the destination MAC address accordingly. i.e • If broadcast flag is set, change the destination MAC as broadcast • If broadcast flag is not set, change the destination MAC to that of ‘chaddr’

  10. Next Step • More review in WG mailing list. • Working group item?

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