[Ospf-manet] Simulation results for MPR adjacency reduction
Richard Ogier <rich.ogier@earthlink.net> Tue, 02 January 2007 20:56 UTC
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Date: Tue, 02 Jan 2007 12:55:42 -0800
From: Richard Ogier <rich.ogier@earthlink.net>
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Subject: [Ospf-manet] Simulation results for MPR adjacency reduction
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All, Since I was curious about the performance of INRIA's solution with MPR adjacency reduction (in addition to MPR LSA reduction), I decided to modify the GTNetS code (the version INRIA released) to implement this, and run some simulations. The GTNetS code I used can be downloaded at: http://home.earthlink.net/~ogier/ospf6d_mpr_adj.tar.gz I include only the directory ospf6d, since everything else is the same as INRIA's release, except that the following line should be uncommented in the Makefile so that MDR can also be run: CFLAGS += -DOSPF6_MANET_MDR_FLOOD The results below give an idea of how MPR-based adjacencies perform based on INRIA's current draft specification. INRIA can probably improve the performance, e.g., by selecting MPRs more persistently, but until that happens, I wanted to see how it performs based on the current specification. The results for 20, 40, and 60 nodes are summarized below, followed by a summary of the code changes. Detailed results for 60 nodes and the parameters values are are given at the end of this message. For INRIA's solution (which is a modification of OR), I used the parameter values recommended by the Cisco OR/SP team and used in Boeing's simulations. As in OR/SP, for both INRIA and MDR, an adjacency is never torn down as long as the neighbor is bidirectional, to reduce the rate at which new adjacencies are formed. Results for MDR with 1-connected adjacencies and min-cost LSAs: 20 nodes 40 nodes 60 nodes -------- -------- -------- Total Overhead (kbps) 21.52 79.08 164.32 LSU overhead (kbps) 5.21 18.05 33.67 DD overhead (kbps) 4.08 18.54 36.28 Adjacencies/node 3.30 3.02 2.88 Adj changes/node/sec 0.04 0.04 0.04 Delivery ratio 0.966 0.951 0.953 Results for MPR-based LSAs and adjacency reduction: 20 nodes 40 nodes 60 nodes -------- -------- -------- Total Overhead (kbps) 48.20 234.12 588.43 LSU overhead (kbps) 10.32 40.08 72.33 DD overhead (kbps) 18.40 119.92 352.89 Adjacencies/node 8.58 15.93 21.93 Adj changes/node/sec 0.15 0.27 0.36 Delivery ratio 0.918 0.924 0.920 Notice that adjacency changes/node/sec stays constant at .04 for MDR, but increases approximately linearly for INRIA. This clearly shows that MPR adjacency reduction is not scalable. The DD overhead is 4.5 times greater for INRIA for 20 nodes, 6.5 times greater for 40 nodes, and 9.7 times greater for 60 nodes (notice the trend). Also notice that for INRIA the DD overhead becomes much greater than LSU overhead for 60 nodes, but for MDR the DD overhead is about the same as the LSU overhead for 20, 40, and 60 nodes. The delivery ratio is significantly greater for MDR than for INRIA. This could be partly due to the lower path/LSA stability of INRIA, since MPRs are not selected persistently (while min-cost LSAs are designed to be persistent), and partly due to the delay in updating MPRs following a link failure (as has been discussed). Code changes: I found the following bugs in INRIA's code: 1. An LSA was originated only when a neighbor goes to/from Full (same as for OR), but with MPR-based LSA reduction, an LSA should be originated whenever the set of MPRs or the set of MPR selectors changes. This problem went away with MPR-based adjacency reduction, since a neighbor becomes Full only after it becomes an MPR or MPR selector (or the router or neighbor is a sync node). 2. In the SPF calculation, the backlink check was not done for MPR-based LSA reduction. The backlink must always be checked for compatibility with OSPFv3 (i.e., the link from node w back to node v must exist). (Let me know if this has somehow changed.) 3. The code was written so that OSPF6_MANET_MDR_FLOOD and OSPF6_MANET_MPR_TOPO_REDUC could not both be defined, i.e., the code had to be compiled separately for the two protocols. Summary of changes: 1. The code was fixed so that OSPF6_MANET_MDR_FLOOD and OSPF6_MANET_MPR_TOPO_REDUC can both be defined, without the code for one protocol interfering with the other protocol. 2. The backlink check is always done. 3. The code now does MPR adjacency reduction, as follows: (a) need_adjacency() was modified so that an adjacency is needed only if the neighbor is an MPR or MPR selector, or the router or neighbor is a sync node. (b) A node determines that it is a sync node if it has a larger RID than all neighbors. This is updated whenever the set of neighbors changes, and is indicated in Hellos by setting the DR field equal to the router's own RID. (A detail not specified in the draft.) (c) Adjacencies are updated whenever the set of MPRs or MPR selectors changes, and whenever the set of neighbors changes. (d) MPRs are no longer required to be Full neighbors, and 2-hop neighbors are no longer required to be Full neighbors of 1-hop neighbors. Note that the modified code cannot run MPR LSA reduction without MPR adjacency reduction, since that would require even more work :-). Richard -------------------------------------- Detailed results for MDR for 60 nodes: ./random_waypoint_manet-opt seed=8 num_nodes=60 pktrate=10 wireless_interface=2 wireless_flooding=2 velocity=10 radio_range=250 alpha=0.5 pause_time=40 HelloInterval=2 RxmtInterval=7 DeadInterval=6 AckInterval=1000 BackupWaitInterval=500 TwoHopRefresh=3 AdjConnectivity=1 LSAFullness=1 start_time=1800 stop_time=2700 Neighbor statistics (at physical layer): -------------------------------------------------- Number of nodes: 60 Neighbor threshold distance (m): 250.00 Average neighbor density (neighbors/# of nodes): 0.63 Average neighbor changes/time (changes/sec/node): 0.30 OSPFv3 Statistics | Packets Bytes Kbps ---------------------------------------------------- Hello | 27000 5849812 52.00 LSAck | 38145 4753120 42.25 LSR | 246 13128 0.12 DBDESC | 4911 4081624 36.28 LSU | 18728 3787764 33.67 LSUfld | 15147 3078988 27.37 LSUuni | 3581 708776 6.30 LSUcol | 7 3704 0.03 LSUrxmt | 3307 655336 5.83 LSUdbex | 243 44928 0.40 LSUstale| 24 4808 0.04 | Total | 89030 18485448 164.32 OSPF Network Characteristics -------------------------------------------------- OSPF 2way_neighbors/node: 37.15 OSPF 2way_neighbor_changes/node/sec: 0.66 avg_sec/OSPF 2way neighbor_life: 121.12 OSPF adjacencies/node: 2.88 OSPF adjacency_changes/node/sec: 0.04 avg_LSAsOutSync: 0.12 Secs per router-LSA origination: 15.81 Router-LSA hopcount/Router-LSA installs: 2.61 Route changes/node/sec: 4.54 Accumulated adjacencies/node: -0.10 Flooding Statistics -------------------------------------------------- relaysel/node: 3.70 avg_sec/relaysel_life: 44.23 suppressed_LSAs: 165040 relay_flood_LSAs: 19259 nonrelay_flood_LSAs: 958 Topology Reduction Statistics -------------------------------------------------- Advertized neighbors: 20752 Total FULL neighbors: 113259 User Traffic Analysis -------------------------------------------------- UDP sends: 8951 pkts, 608668 bytes UDP receives: 8529 pkts, 579972 bytes UDP forwards: 3748 pkts, 254864 bytes Delivery Ratio: 0.953 ------------------------------------------ Detailed results for INRIA for 60 nodes: ./random_waypoint_manet-opt seed=8 num_nodes=60 pktrate=10 wireless_interface=2 wireless_flooding=1 velocity=10 radio_range=250 HelloInterval=2 RxmtInterval=9 DeadInterval=6 PushbackInterval=7000 AckInterval=500 MinLSInterval=5 velocity=10 start_time=1800 stop_time=2700 TopoReduc Neighbor statistics (at physical layer): -------------------------------------------------- Number of nodes: 60 Neighbor threshold distance (m): 250.00 Average neighbor density (neighbors/# of nodes): 0.63 Average neighbor changes/time (changes/sec/node): 0.30 OSPFv3 Statistics | Packets Bytes Kbps ---------------------------------------------------- Hello | 27000 6109348 54.31 LSAck | 85432 12017232 106.82 LSR | 4147 234588 2.09 DBDESC | 51672 39700376 352.89 LSU | 61758 8137020 72.33 LSUfld | 50603 6587356 58.55 LSUuni | 11155 1549664 13.77 LSUcol | 112 27252 0.24 LSUrxmt | 4953 502816 4.47 LSUdbex | 3929 795020 7.07 LSUstale| 2161 224576 2.00 | Total | 230009 66198564 588.43 OSPF Network Characteristics -------------------------------------------------- OSPF 2way_neighbors/node: 37.06 OSPF 2way_neighbor_changes/node/sec: 0.71 avg_sec/OSPF 2way neighbor_life: 111.63 OSPF adjacencies/node: 21.93 OSPF adjacency_changes/node/sec: 0.36 avg_LSAsOutSync: 0.27 Secs per router-LSA origination: 5.66 Router-LSA hopcount/Router-LSA installs: 2.15 Route changes/node/sec: 13.33 Accumulated adjacencies/node: 0.57 Flooding Statistics -------------------------------------------------- relaysel/node: 2.87 avg_sec/relaysel_life: 12.06 suppressed_LSAs: 439557 relay_flood_LSAs: 34974 nonrelay_flood_LSAs: 24216 Topology Reduction Statistics -------------------------------------------------- Advertized neighbors: 37634 Total FULL neighbors: 357653 User Traffic Analysis -------------------------------------------------- UDP sends: 8951 pkts, 608668 bytes UDP receives: 8237 pkts, 560116 bytes UDP forwards: 3105 pkts, 211140 bytes Delivery Ratio: 0.920 ----------------------- _______________________________________________ Ospf-manet mailing list Ospf-manet@ietf.org https://www1.ietf.org/mailman/listinfo/ospf-manet
- [Ospf-manet] Simulation results for MPR adjacency… Richard Ogier
- Re: [Ospf-manet] Simulation results for MPR adjac… Emmanuel Baccelli
- Re: [Ospf-manet] Simulation results for MPR adjac… Richard Ogier