Stretched Subnet

scotthellewell · August 5, 2015, 1:10am

I am wanting to create a stretched subnet between 3 locations. I have 2 routers at each location running OSPF and OSPFv3 to distribute internal routes and BGP to distribute external routes. Each location is connected to the other locations via 2 metro ethernet connection, 2 different service providers for redundancy. This all works well other than I have to limit my BGP routing tables with a filter that limits the number of prefixes each router receives. (add action=discard bgp-as-path-length=3-4294967295 chain=eBGP-in)

The routers are all CCR1016-12S-1S+

Location 1: 19-R1 and 19-R2
Location 2: CT-R1 and CT-R2
Location 3: VW-R1 and VW-R2

What would be the best way to do the stretched subnet for these 3 locations? Would I setup a EoIP link between each router and the the other 5 routers and then create a bridge on each router bridging all of the EoIP links as well as a vlan interface on the routers and then run VRRP on each router to create a default gateway?

Does anyone have a better suggestion?

The stretched subnet will be for a SQL Server Always On Availability group with SQL servers at each physical location.

It seems like there would be some kind of better solution, but I am not sure what it is. Maybe it would relate to the use of MPLS or something similar. I haven’t done any MPLS solutions at this point and if that is the way to go, I could use some good examples.

Thanks,

Scott Hellewell

scotthellewell · August 5, 2015, 2:12pm

I attempted to setup VPLS with BGP. I tried following http://wiki.mikrotik.com/wiki/Manual:BGP_based_VPLS. I could get the connections to distribute with BGP, but no traffic seemed to transfer over it. It might be related to our metro ethernet circuits and maybe MTU. I am not sure what they allow.

After that I tried EoIP circuits with a full mesh of them. Then put them all in a bridge on each router with a horizon of 1 and also bridged in a vlan interface. It all seems to work. I am able to ping all of the locations and also ping a server I but on the vlan.

Thanks,

Scott Hellewell