Ways to connect two routers

Nikolaos Milas · ‎04-15-2015

Hello,

We have two routers connected as shown in the diagram:

We would like to create a one-hop connection ("peering") between the two routers (over the link shown) for routing purposes (iBGP, OSPF, static routes).

What are the suggested way(s) to do it?

Method 1: We have tried creating two GRE tunnels (one for IPv4 and one for IPv6) and it works but we are having various issues (which we are still troubleshooting)

Method 2: We could create IPSec tunnels; I have not tried it.

Method 3: This is my main question here. Can we define a common VLAN on the two routers so that, by using trunk links in-between, the two interfaces (actually a new subinterface of each: R1,G0/0.x - R2,G0/1.x) can coexist "alone" on one VLAN?

Other suggested methods please?

Thanks in advance for your assistance.

Regards,
Nick

Reza Sharifi · ‎04-15-2015

Hi,

For method 3: As long as all the devices between the 2 routes are capable of dot1q trunking, you can simply configure each to be a layer-2 device with dot1q, than the 2 routers will see each other as being in the same subnet/vlan.

HTH

Nikolaos Milas · ‎04-15-2015

Thank you very much for your reply which revives my hopes for such a solution.

Unfortunately, I have been having problems making it work. See the following thread:

https://supportforums.cisco.com/discussion/12477986/using-different-native-vlans-different-ports-switch-configured-trunks

The wireless devices have been already configured to support trunk traffic, as described here:

http://community.ubnt.com/t5/airOS-Software-Configuration/VLANs-and-Nanostation-M5/td-p/476513

Any recommendations will be very welcome!

Thanks,
Nick

snared04drummer · ‎04-15-2015

Given the design, I would think a GRE tunnel would be the desired method for connecting these two devices.

Perhaps you could post the output of the interface and tunnel interface configurations that you have, and we can take a look at them?

Nikolaos Milas · ‎04-15-2015

Thanks for the reply.

Here is the current setup:

{View image and zoom in to full scale for clearer reading!}

With this configuration, the tunnels seem to be working correctly, however we are still having a problem: When I switch traffic so that it uses the tunnels, netflow export from R1 to a netflow server (using nfdump/nfsen) which is located at a LAN connected to R2, is not recorded correctly; I see (on R1):

# sh ip flow export
Flow export v9 is enabled for main cache
  Export source and destination details :
  VRF ID : Default
    Source(1)       195.251.xxx.yyy (Loopback0)
    Destination(1)  195.251.xxx.xxx (9995)
  Version 9 flow records
  680074 flows exported in 8490 udp datagrams
  0 flows failed due to lack of export packet
  1579 export packets were sent up to process level
  0 export packets were dropped due to no fib
  0 export packets were dropped due to adjacency issues
  0 export packets were dropped due to fragmentation failures
  0 export packets were dropped due to encapsulation fixup failures

and I find that our traffic is not recorded correctly. (When we don't use these tunnels -but another route not shown in the diagram, which does not involve tunnels- then "export packets sent up to process level" are 0 and netflow export works correctly.)

Netflow monitoring is critical to our network, so we have to troubleshoot this, before we can use this configuration in production. (I am thinking of opening a new thread for this problem.)

Any and all suggestions will be welcome.

Nick