tloc-extension design

[JW_UK]

The recommendation for branch office TLOC-extension appears to be direct connection between the two SD-WAN routers.

I am interested to know if there is a reason for this when compared to the option 2 and 3 in the diagram, for example:

-is there a technical reason why direct connection (opt1) is better?

-Is option 2 acceptable and what would be needed on the LAN to support this model

[HashamM]

Option 2 and 3 are adding more point of failures. It is recommended to have a direct link between the WAN edge routers for tloc-extension.

[JW_UK]

Hi HashamM,

Thanks for the reply, if opt 2 was used for L2 adjacency , do you know of any config that would be needed on the switch (e.g QOS), or would a standard trunk port suffice?

Regards, James.

[HashamM]

I am not aware of any special QOS requirement on the switch. But should have portfast enabled to avoid switch waiting for STP timers to start traffic flows.

[JW_UK · Accepted solution]

I agree opt#1 is best.

For sites with multiple switch stacks and where routers connect to unique switches it would still be possible to use both WAN transports during switch failure (from the remaining live switch).

Op#2 & 3 would prevent this from happening as the tloc-ext is dependant on the LAN.

Thanks for your help!

[tranminhc]

Hi,

Is that possible to use HWIC-4SE ports layer 2 then interface VLAN as TLOC extension between two Router. My ISR4321K9 has only two ports Layer3 and 4 port Layer2.

Thanks

Ccc

[bruno.fernandes]

Hi trenminhc,

Did you came to any conclusion around your question ?

I have the same sort of question with ISR-1121X

Regards,

Bruno

[tranminhc]

I don't have yet. Actually it's NIM-ES2-4 module, not hwic.

[Sanket A]

Looking for more details on Option#2.

Any reference documents would be great help.