[Olsr-users] olsr2 and multipath

[Henning Rogge]

On Mon, Nov 14, 2016 at 10:17 AM, Ansgar Jazdzewski <
(spam-protected)> wrote:

> Hi,
>
> i am try to setup a new smal datacenter and we like to test olsr2 as
> the layer3-dataplane.
>

What kind of multipath are you expecting? Do you just want to use parallel
ethernet links between certain nodes or do you have "real" disjunct paths?


>
> wath i have done so far is:
>
> bring all my NICs up with a IPv4 link-local and set a host ip on loopback.
> olsr is running so far, but i can not see any multipah in my routing-table
>
> ####
> (spam-protected):/home/sprd# ip rout show
> default via 172.16.162.1 dev eno2  proto 100  src 172.16.162.167
> metric 2 onlink
> default dev eno2  scope link  metric 1003
> 169.254.0.0/16 dev eno2  proto kernel  scope link  src 169.254.8.60
> 169.254.0.0/16 dev eno1  proto kernel  scope link  src 169.254.8.55
> 172.16.162.1 via 172.16.162.1 dev eno2  proto 100  src 172.16.162.167
> metric 2 onlink
> 172.16.162.156 via 169.254.22.61 dev eno2  proto 100  src
> 172.16.162.167  metric 2 onlink
> 172.16.162.161 via 169.254.12.73 dev eno2  proto 100  src
> 172.16.162.167  metric 2 onlink
> 172.16.162.178 via 169.254.9.132 dev eno2  proto 100  src
> 172.16.162.167  metric 2 onlink
> ####
> (spam-protected):/home/sprd# ip -4 addr show dev lo
> 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN
> group default qlen 1
>    inet 127.0.0.1/8 scope host lo
>       valid_lft forever preferred_lft forever
>    inet 172.16.162.168/32 scope global lo
>       valid_lft forever preferred_lft forever
>    inet 172.16.162.167/32 scope global lo
>       valid_lft forever preferred_lft forever
> ####
>
> so my questions are:
> how can i configure it, or is multipath no possible with olsr2?
>

OLSR and OLSRv2 do not support multipath at the moment (at least the
OLSR.org implementation does not have any extensions for it)... mostly
because the Dijkstra Algorithm gives you only the "fastest" path and it is
quite difficult (especially for a mesh net environment) to suggest an
algorithm that gives you multiple good paths.

see https://tools.ietf.org/html/draft-ietf-manet-olsrv2-multipath-11 for
some standardization work on it in the IETF.

If you have a good idea how to implement an algorithm like this I would
like to talk about it.

There is also the problem that moving the traffic along these paths is
difficult without a very special setup or source routing (which is
deprecated I think).

Henning Rogge


> Tanks
> Ansgar
>
> --
> Olsr-users mailing list
> (spam-protected)
> https://lists.olsr.org/mailman/listinfo/olsr-users
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