[Olsr-users] Question about listed HNA networks and "active" olsr interfaces

Teco Boot (spam-protected)
Wed Oct 12 16:02:41 CEST 2011


Oeps. I use same addressing scheme for mesh links and wired links in 
an ad hoc fashion (routers with back to back cross-cable). So maybe
better to make it optional.

FYI, the proposal does't break anything, but has some overhead (HNA 
messages) and does not solve the sketched problems in my case. Because 
the common subnet is configured on all my wired glue segments, and these
are not one broadcast domain, traffic to a non-olsr node on a far away 
glue segment is routed to a nearer glue segment, if such exists.

Teco


Op 12 okt 2011, om 15:38 heeft Teco Boot het volgende geschreven:

> Responding on original mail:
> 
> The Ethernet is a normal subnet, right? And high speed, so it makes sense
> to prefer it over the mesh link. So with LinkQualityAlgorithm "etx_ffeth"
> and Mode "ether" olsrd knows how to handle it.
> 
> For mesh interfaces, a longest match prefix (/32, /128) is made reachable
> for all nodes in the network. Each such prefix has separate routes on each
> router. Some say the host prefix is to be configured on the mesh interface
> (RFC5889). But this results in remote reachability problems is routing daemon
> was stopped. Therefore, RFC5889 is not practical, and shorter prefix lengths
> are used for configuring the interface. So we have different subnet lengths
> for mesh interfaces itself and the routes to it.
> 
> For ether interfaces, we could turn off this host prefix length injection 
> mechanism and send out HNA for the connected subnet. This is how routers 
> usualy work.
> 
> So yes, I support a change:
>  On interfaces that are up and mode for that interface is "ether": send out an
>  HNA with configured prefix for that interface.
> 
> Teco
> 
> Op 12 okt 2011, om 14:28 heeft ZioPRoTo (Saverio Proto) het volgende geschreven:
> 
>> Hello,
>> 
>> I did not understand the detail of your setup, however:
>> 
>> 1) it is fine to have multiple nodes in the network announcing via HNA
>> the same prefix, as long as these node are really connected with some
>> interface to that subnet
>> 
>> 2) hna is a global configuration parameter for the olsrd demon, so the
>> prefix will be announced whatever is the state of the interfaces.
>> However you open here a discussion about a potential new feature of
>> binding a HNA prefix to a Interface status. I'll discuss this on a
>> separate thread.
>> 
>> Saverio
>> 
>> 
>> 2011/9/27 Eric Malkowski <(spam-protected)>:
>>> Hi All-
>>> 
>>> It's been a while since I've posted here and I'm still using OLSR 0.5.8-r6
>>> (latest stable of that series before 0.6.X came out).
>>> I have a basic question about listing networks as HNA in the config and the
>>> "Active" interfaces one does OLSR on.
>>> 
>>> I usually never list a subnet in the HNA list at the beginning of the config
>>> file AND list the interface that the HNA subnet is tied to for "active" OLSR
>>> at the end of the file.  I have run into a situation where it would be
>>> beneficial to do this.  Is it OK to do this?
>>> 
>>> An example could be like this -- two typical mesh + ap nodes out of range of
>>> each other but connected with a simple wired interface:
>>> 
>>> Outdoor node:
>>> 
>>> ath0  AP network listed only as HNA 10.23.0.1/16
>>> ath1  Mesh 10.5.0.3/24   (does active OLSR, NOT listed as HNA in config)
>>> eth0  Glue network 10.0.3.1/24  (does active OLSR NOT listed as HNA in
>>> config)
>>> 
>>> Other node connected by wired link:
>>> 
>>> eth0  Glue network 10.0.3.2/24 (does active OLSR NOT listed as HNA in
>>> config)
>>> ath1  Mesh 10.5.0.5/24  (does active OLSR, NOT listed as HNA in config)
>>> ath0  AP network listed only as HNA 10.25.0.1/16
>>> 
>>> I've found that even though the two ath1 interfaces (on same subnet) are
>>> separated by the wired link, clients on each ath0 networks of either node
>>> enjoy connectivity everywhere.
>>> 
>>> What I do is have one of the two nodes act as a convenience DHCP server on
>>> eth0 so if someone plugs in a wired client, they can get an IP.  If internet
>>> is available, the default route gets them internet access.  However since
>>> the eth0 network 10.0.3.1/24 is not listed as an HNA by at least ONE of the
>>> two nodes, someone on eth0 w/ a DHCP address may not be able to get
>>> everywhere since only host routes are listed for 10.0.3.1 and 10.0.3.2.
>>> 
>>> I'd like to simply have each node list their eth0 10.0.3.0/24 network as an
>>> HNA in the config.  Any ideas if this will be a problem?  As I said, I
>>> normally don't configure an interface for active OLSR AND to be listed as
>>> HNA in the config at the same time as it didn't seem like the right thing to
>>> do, but I'm thinking to keep everyone to have full connectivity everywhere
>>> who might grab an IP from the networks on ath0 or eth0 of each node, it
>>> would make make sense that the eth0 10.0.3.0/24 network is listed as HNA in
>>> one of the two nodes' config files or both.  The more I think about this I
>>> would think it should be fine.
>>> 
>>> I hope this makes sense.
>>> 
>>> Thanks,
>>> 
>>> -Eric Malkowski
>>> 
>>> 
>>> 
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>>> https://lists.olsr.org/mailman/listinfo/olsr-users
>>> 
>> 
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