1. Kurt Windisch -- University of Oregon ANTCIETF GATED -- March 30, 1998 1 PIM Dense Mode GateD Implementation Kurt Windisch Advanced Network Technology Center University of Oregon

2. Kurt Windisch -- University of Oregon ANTCIETF GATED -- March 30, 1998 2 Outline n PIM-DM Overview n GateD PIM-DM Design and Implementation n Current Status n Testing n Issues n http://www.antc.uoregon.edu/GATED/

3. Kurt Windisch -- University of Oregon ANTCIETF GATED -- March 30, 1998 3 PIM-DM Overview Key Features (PIM version 2): n Protocol Independent: ä Uses multicast RIB updated by existing unicast routing protocols for RPF lookups n Data-driven flood-and-prune strategy n Builds optimal source-based trees: O(S x G) state n Soft state draft-ietf-idmr-pim-dm-06.txt, S. Deering, D. Estrin, D. Farinacci, V. Jacobson, D. Meyer, L. Wei

4. Kurt Windisch -- University of Oregon ANTCIETF GATED -- March 30, 1998 4 Implementation Details n Compliant with PIM v2 specification ä but uses SM spec timer defaults n Based on GateD PIM-Sparse implementation by George Eddy (ISI) n Shared PIM code (SM/DM) n Requires PIM Kernel Patches (bug fixes)

5. Kurt Windisch -- University of Oregon ANTCIETF GATED -- March 30, 1998 5 PIM-DM GateD Architecture pim pimsm pimdm mbrmroute kernel igmp PIM protocol packets MFC maint. alerts PIM protocol packets neighbor state maint. MFC maint. alerts MFC stats group state

6. Kurt Windisch -- University of Oregon ANTCIETF GATED -- March 30, 1998 6 MBR Alerts n Creating routing state ä sg_creation_recv : creates (S,G) entry with forwarding state (implements flooding) n Outgoing interface changes ä sg_join_recv : PIM-DM sends (S,G)-Graft upstream –if not triggered by creation flooding ä sg_prune_recv : PIM-DM sends (S,G)-Prune upstream –w/ rate-limiting on P2P links

7. Kurt Windisch -- University of Oregon ANTCIETF GATED -- March 30, 1998 7 MBR Interactions n RPF check ä wrongif_recv : PIM-DM rate-limits (S,G)-Assert or Prune on receiving interface n Group membership changes ä igmp_add ä static_join_recv ä igmp_delete n Unicast route changes ä flash : updates MRT when upstream nbr changes aux_join_recv

8. Kurt Windisch -- University of Oregon ANTCIETF GATED -- March 30, 1998 8 PIMDM MRT source data n pimdm_source_t contains dense-mode- specific data structures for (S,G) entry: ä src_prune : list of pruned downstream interfaces ä src_scheduled_jp : list of time-delayed i/f prune actions and join transmissions on a LAN ä src_assert_timeout : timeout for upstream assert winner ä src_rlt : last prune and assert send times for rate- limiting ä src_graft : pointer into global list of grafting source entries ä src_jp_alert_suppress : boolean indicating whether to heed join/prune MBR alerts (used when creating entry)

9. Kurt Windisch -- University of Oregon ANTCIETF GATED -- March 30, 1998 9 PIMDM MRT source data source_t src_data[] … src_prune src_scheduled_jp src_assert_timeout src_rlt src_graft src_jp_alert_suppress pimdm_source_t MRT downstream_t (pruned i/f list) … pimdm_scheduled_jp (delayed joins/prunes) … pimdm_rate_limit_times_t ((S,G) assert/prune times for each i/f … mrt_src_list_t (list of grafting all entries) …

10. Kurt Windisch -- University of Oregon ANTCIETF GATED -- March 30, 1998 10 Current Status n Changes since last GateD meeting: ä static joins ä administrative scoped boundaries ä redesigned Grafting ä bug fixes: neighbors, asserts, p2p, termination/reconfiguration… thank you for your bug reports! ä continued testing

11. Kurt Windisch -- University of Oregon ANTCIETF GATED -- March 30, 1998 11 Known Bugs n Out-of-order datagram arrival (intermittent) ä Problem : On assert election downstream routers receive all asserts before data ä Result : assert state is lost before (S,G) state created ä Still debugging ä Possible work-around : delay notification assert send from winner by 1 sec.

12. Kurt Windisch -- University of Oregon ANTCIETF GATED -- March 30, 1998 12 Testing n Manual testing n Test scripts (using GaTT Tcl testing library) ä Basic PIMv2 Neighbor Interaction ä Basic PIM-DM v2 Flood and Prune ä PIM-DM v2 Multiaccess LAN Prune/Join ä PIM-DM v2 Multiaccess LAN Assert ä PIM-DM v2 Graft Retransmission and Ack all pass with 3/20/98 pimdm code! See: http://antc.uoregon.edu/GATED/

13. Kurt Windisch -- University of Oregon ANTCIETF GATED -- March 30, 1998 13 Testing ToDo List n Cisco interoperability test scripts n PIM border router interop, especially: ä PIM-DM DVMRP ä PIM-DM PIM-SM n General point-to-point operations n ATM (?)

14. Kurt Windisch -- University of Oregon ANTCIETF GATED -- March 30, 1998 14 Issues n Inconsistencies in PIM SM and DM specs (DM spec relies on SM spec for some details) n Timeouts ä Whether to use default timer values from SM specs (ID and/or RFC2117) or DM spec. – My answer : use SM defaults (except assert timeout)

15. Kurt Windisch -- University of Oregon ANTCIETF GATED -- March 30, 1998 15 Issues n Timeouts (cont) ä Assert Timeout must equal Prune Holdtime –SM spec (ID and RFC2117) says assert=180s and prune=210s. – Problem: Downstream router switches to back RPF before new assert election takes place. – Result: Joins and Prunes sent upstream to the LAN will have incorrect addr in upstream nbr field and will be ignored by the (S,G)- forwarder. – My Fix: set assert timeout to 210s.

16. Kurt Windisch -- University of Oregon ANTCIETF GATED -- March 30, 1998 16 Issues n Timeouts ä Join and Prune delay inconsistencies in spec –SM specs say 4.5s but DM spec says 3s – My answer : for interoperability with all implementations: n listen for joins for 5 seconds before pruning n send joins after a random delay of less than 3 seconds

17. Kurt Windisch -- University of Oregon ANTCIETF GATED -- March 30, 1998 17 Issues n Prunes on point-to-point links ä send to IP multicast address or destination or remote unicast addr? ä Remote addr or 0.0.0.0 in upstream neighbor field of Join/Prune packet? n Implementation of new Hello options ä draft-ietf-idmr-pimv2-dr-priority-00.txt ä others in the works

18. Kurt Windisch -- University of Oregon ANTCIETF GATED -- March 30, 1998 18 My Interests n Continue to develop, debug, and maintain pimdm for GateD n Develop PIM-Dense extension to Ahmed and Pavlin’s PimD. n Develop PIM sparse-dense mode for GateD (ala Cisco) n … ?