Hello,
you cannot use LACP between 3 devices. That is only possible if two of
those devices (Force10 routers/switches) are forming one logical device
(Cisco VSS, MEC, virtual PortChannel, HP IRF), I don't know if Force10
has something like that. If you do this however, those 2 routers will
appear as one logical device (one OSPF neighbor) to the server, then you
don't have a problem. This is preferred solution, because it takes the
problem from OSPF to much faster technologies.
On the other hand you can do VRRP between the routers and do OSPF on the
hypervisor with both of the routers, in this case just beware the
asymetric routing (which may/may not be a problem, depending on the
setup).
Regarding your setup, I assume you're using the same IP on both of the
routers, this won't work because from the router perspective the links
are UP and they're advertising the same /31 to the rest of the network,
this will cause half of the packets/flows to be lost.
So, you can either use some virtualization switching technology (if
Force10 provides that), or you can use VRRP with 2 OSPF neighborships
(but in that case you need /29 subnet), or you can do some sort of
script on the server and use master-slave bonding mode, but be sure to
always shutdown the inactive interface (be sure to always have enabled
only one of them physically), that way only one of the Force10 routers
would advertise the subnet...
Martin
2013-12-16 10:24 odosielateľ napísal:
Yes - the reason is that this router is a VM with two passthrough NICs.
The hypervisor is connected to both Force10 routers/switches with
LACP, so the VM needs to run linux bonding mode 2 to provide a bond0
interface to the VM.
Neighbourship then needs to be established to both routers on this
bonded interface.
I tried to create neighbourship directly on the interfaces, but this
does not work, I assume because the switches loadbalance traffic on
the LACP portchannel.
I could create a neighbourship with a VRRP interface, but as I
understand it this will not work due to different router-ids in case
of failover.
So basically as I see it, this is the only way to make this work -
unless you have another idea?
Thanks
Regards
Kristoffer
On 13/12/2013, at 17.37.29, Raphael Mazelier <r...@futomaki.net> wrote:
I?m trying to use a bonded interface on linux to connect to two
routers, one router on each physical link, each with a /31 subnet.
Only one of the routers (Force10 S4810) forms adjacency with the
linux host (whichever comes first), the other gets stuck in EXSTART
until I shut/no shut the link, then Bird creates adjacency with both
routers.
What are you trying to do with this design ? It's rather strange.
--
Raphael Mazelier
