OLSR Scaling Analysis

1
OLSR Scaling Analysis
2
Parameters Used

• N network size
• d density ( of one-hop neighbors)
• k network diameter (not used)
• f of distinct flows (not used)

3
Link Set

• Interfaces recently heard
• d entries
• (L_local_iface_addr, L_neighbor_iface_addr,
  L_SYM_time, L_ASYM_time, L_time)
• Propagated by HELLO messages

4
Multiple Information Association Set

• Notice about multiple interfaces
• Up to N entries
• (I_iface_addr, I_main_addr, I_time)
• Propagated by MID messages

5
Neighbor Sets

• 1-hop and 2-hop neighbors
• d entries and up to d2 entries
• 1-hop (N_neighbor_main_addr, N_status,
  N_willingness)
• 2-hop (N_neighbor_main_addr, N_2hop_addr,
  N_time)
• Propagated by HELLO messages
• MPR Set - subset of neighbor set

6
MPR Selector Set

• Nodes that chose me as an MPR
• Up to d entries
• (MS_main_addr, MS_time)
• Propagated by HELLO messages

7
Topology Set

• Path information
• O(N) entries - at least one for N nodes
• (T_dest_addr, T_last_addr, T_seq, T_time)
• Propagated by TC messages

8
Routing Table

• Recalculated if link, topology, neighbor, 2-hop
  neighbor, or multiple association set changes
• (R_dest_addr, R_next_addr, R_dist, R_iface_addr)

9
HELLO Messages

• Broadcast to all 1-hop neighbors (d messages)
  periodically
• 4 bytes (d address size) bytes for each set
  (link set, 1-hop neighbor set, MPR set)
• Must advertise all symmetric 1-hop links on all
  interfaces

10
TC Messages

• Flooded to entire network (at least N messages)
  by MPRs
• Proactive (periodic) messages and reactive
  messages

11
MID Messages

• Sent ONLY if node has multiple interface
  addresses
• Contains interface address for each interface on
  the node except the main address
• Flooded to entire network periodically using MPRs

12
Scaling Issues

• Routing Table recalculated frequently
• Large HELLO messages sent often (entire neighbor
  set)
• TC Set can grow too quickly

13
Collection

• All-to-one or All-to-some
• MPR set is all parents and children in tree
• Topology only needed for path to root(s)

14
Dissemination

• One-to-all
• MPRs help limit messages in flood
• MPR set is all parents and children in tree
• Topology not needed for ancestors

15
Packet 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
• ----------------------
  ----------
• Packet Length Packet
  Sequence Number
• ----------------------
  ----------
• Message Type Vtime
  Message Size
• ----------------------
  ----------
• Originator Address
  
• ----------------------
  ----------
• Time To Live Hop Count
  Message Sequence Number
• ----------------------
  ----------
• 
  
• MESSAGE
  
• 
  
• ----------------------
  ----------
• Message Type Vtime
  Message Size
• ----------------------
  ----------
• Originator Address
  
• ----------------------
  ----------

16
HELLO Message 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
• ----------------------
  ----------
• Reserved Htime
  Willingness
• ----------------------
  ----------
• Link Code Reserved
  Link Message Size
• ----------------------
  ----------
• Neighbor Interface
  Address
• ----------------------
  ----------
• Neighbor Interface
  Address
• ----------------------
  ----------
• . . .
  
• 
  
• ----------------------
  ----------
• Link Code Reserved
  Link Message Size
• ----------------------
  ----------
• Neighbor Interface
  Address
• ----------------------
  ----------

17
TC Message 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
• ----------------------
  ----------
• ANSN
  Reserved
• ----------------------
  ----------
• Advertised Neighbor Main
  Address
• ----------------------
  ----------
• Advertised Neighbor Main
  Address
• ----------------------
  ----------
• ...
  
• ----------------------
  ----------