Software router

Good times!

We are starting to play around with VMware SRM and they "virtual" subnets
that supposedly have to be able migrate from site to site in case of a
failure of the local hardware (or software).
Seems like to do that I'd have to run a software router on a VM that would
redistribute the "virtual" subnet into the physical routing domain.
does any one have any suggestions for a software router?

I'm running EIGRP on the net, so I guess nothing will speak that, so I'd
have to redistribute OSPF. Any OSPF software router software suggestion
would be much appreciated.

Or if anyone had implemented "floating" subnets, any other suggestions or
what to look out for would be also much appreciated.

Thank all in advance,

Really not core network related as it never touches a wire, let alone the core, but try


Mikrotik would fit the bill.

Vyatta has a VMWare image. Have used and is pretty good. community edition or commercial supported.


Openbsd makes a mighty fine router. Includes support for OSPF and BGP
out of the box.

Cory Struth

I second Vyatta. I've played with it quite a bit and found it to be
extremely functional.


For a VM router (for performance reasons is different than what i'd
suggest for a generic software router), I would suggest picking an
off-the-shelf OS that Vmxnet2 or Vmxnet3 drivers are available for,
see KB1001805, make sure to install the VM tools, change vNICs' type
to vmx. Standard OS + quagga, openbgpd, or other. Vyatta should
be great, if you are able to compile the vmx drivers for it.

Hopefully you are not planning to forward high-PPS traffic through a
single VM; vNICs are potentially a serious bottleneck in that

If traffic is not trivial, I would suggest using third-party
next-hop routing, that is, with VM-based routers removed from
forwarding path, by acting as route server, or announcing as next-hop
another (real) third-party router's IP instead one of its own IPs
(requiring all 3 routers to share a subnet).

Or investigate layer 2 extension of an upstream subnet via L2TPv3
pseudo-wire service, or Cisco OTV, etc....
then design failover scenario to not require a VM involvement.

Another thought is OSPF /32 host advertisements on some 'beacon'
VM(s), with tracked routes for 'virtual subnet' selection, instead
of a "router" VM.

Those are some vague thoughts... I'm just saying, almost anything,
other than having a VM forward packets for subnets, if it is
avoidable, even tunnelling -- on a non-VM router... :slight_smile:

RouterOS does run in virtual environments, super small, and has BGP,
OSPF, firewalling, etc., all built right in.