Direct transfers should not pay mediation fees

[rakanalh]

Intro

In #4760, a 2% mediation fee gets added to a certain transfer per hop. This is currently causing problems in the scenario where the target is a direct neighbour of the initiator.

Using internal routing, when no mediation takes place and a transfer is direct between X & Y, there should be no mediation fees added to the transfer.

[LefterisJP]

In #4760, a 2% mediation fee gets added to a certain transfer per hop

No the mediation fee percentage is for the entire route since internal routing does not have a good educated guess for the number of hops.

Using internal routing, when no mediation takes place and a transfer is direct between X & Y, there should be no mediation fees added to the transfer.

Yep! Also the PR for this should add a test that there are no fees involved in direct transfers.

[palango]

No the mediation fee percentage is for the entire route since internal routing does not have a good educated guess for the number of hops.

I think this is wrong. The code does know how many hops are in the path.

[LefterisJP]

I think this is wrong. The code does know how many hops are in the path.

Yes it does. My bad, wanted to say that it does not have the latest view of the hops as the PFS does.

[rakanalh]

@LefterisJP question:

raiden/raiden/routing.py

Lines 213 to 215 in f8084c4

	# https://github.com/raiden-network/raiden/issues/4751
	# Internal routing doesn't know about fee so it should set a percentage per hop
	estimated_fee = FeeAmount(round(INTERNAL_ROUTING_DEFAULT_FEE_PERC * amount))

I can see that the estimated_fees are for the whole route... does this make the comment above the calculation invalid?

[LefterisJP]

I can see that the estimated_fees are for the whole route... does this make the comment above the calculation invalid?

Yes the comment is wrong in this case. Please change it.