Hi,
There is a big difference in how the packets are processed.
The regular RIPv2 sets a route to a specific subnet via the sender and
interface where the RIP broadcast was received on. The gateway
information is used only as an optimization element, in case a route
with to that gateway already exists so that the one with the lower
metric gets chosen.
In our case, we use the RIP announcements to transport the subnet AND
gateway information.
So, assuming a point to multipoint interface, if there is let's say an
announcement 44.128.0.0/24 via 1.2.3.4 coming from 44.0.0.1 on the ipip0
interface, regular RIPv2 would translate this to:
44.128.0.0/24 via 44.0.0.1 if ipip0
while ampr rip would translate this to:
44.128.0.0/24 via 1.2.3.4 if ipip0
In the first case, traffic to 44.128.0.0/24 is sent directly to the
gateway (the RIP sender), while in the second case it is encapsulated to
1.2.3.4.
On a mikrotik router it even goes a step further:
it creates a ipip tunnel interface, ampr-1.2.3.4 to 1.2.3.4 and creates
a route
44.128.0.0/24 via ampr-1.2.3.4
This is the processing in the usual case, for 44 subnets having a 44net
gateway we assume that the gateway is published by BGP and is directly
reachable, so for a announcement like 44.128.0.0/24 via 44.128.0.1 there
are 2 route set:
44.128.0.1 via default-gw (which is autodetected), and
44.128.0.0/24 via 44.128.0.1 if ipip0 to do the encapsulation
So, while the information structure in both cases conforms to the RIPv2
specifications, its usage is completely different.
Marius, YO2LOJ