Re: Dialup over Ethernet

Chiming in here..

On Thu, Sep 14, 2017 at 9:05 AM, Hamish McGlinn <[email protected]> wrote:

> I'm of the same opinion as Peter on this. I'm firmly in the PPPoE camp.
>
> Generally speaking the only real case of opposition is the MTU at 1492.
> However in saying this I feel like it is a non issue with mss adjustment.
> If the software takes note of the change in mss then there shouldn't be a
> problem. UDP deployments as far as I have come across are only small
> packets so once again a non issue.
>


Yup, everyone who doesn't like PPPoE seems to complain about the 1492
packet size. But almost all cheap CPEs tend to do tcp mss adjustment
automatically. All the big name firewalls (Juniper, Cisco, Fortigate) have
an option for it. Finally, as a last resort at our end we can do something
funky :

term tcp-helper {
    from {
        protocol tcp;
        tcp-flags syn;
    }
    then {
        forwarding-class best-effort;
        routing-instance vr_tcp_mss;
    }
}

(we just do that in one direction)

And then send those packets through a TCP MSS adjuster. This works well for
the rare case where the customer can't do it.

Really, the 1492 packet size is just a non issue.

Cheers
Dave

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