[OLSR-users] When does a node use ARP?
Sat Jul 8 17:16:55 CEST 2006
I have a question regarding priorities in routing tables and ARP.
I understand that in a routing table, where entries have overlapping
netmasks, the narrower netmask has priority. This is often the case with
OLSR where nodes advertise themselves as /32 routes by default, and their
network interfaces have wide netmasks - such as /8 or /16.
I am wondering - can an OLSR node communicate with a one-hop non-OLSR node
if there is a HNA present with a netmask that overlaps the non-OLSR node?
Consider this scenario:
Node A has a wireless interface with the IP address 10.10.0.1/16 and is
Node Z is running OLSR and is injecting a HNA of 10.10.0.0/17 onto the
network and is many hops away from Node A
Node B is has a wireless interface with the IP address of 10.10.0.2/16 and
is within radio range (and therefore Ethernet range), of Node A but does not
My question is - If Node A, with an empty ARP cache, attempts to communicate
with Node B - what happens? Normally Node A would send an ARP broadcast and
Node B would answer it. But does the /17 HNA from Node Z interfere with
this? Would Node A consult it's routing table and decide that the traffic
should go via Node Z, unaware that Node B is within direct Ethernet range?
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