I am just moving from Quagga 1.2.4 to FRR 7.4.
I noticed that FRR differs in behavior in case of multiple IPv6 default
routes
with the interface line protocol being down.
The quagga static route configuration is:
ipv6 route ::/0 carp3 100
ipv6 route ::/0 <IPv6-PREFIX>::1 carp3 100
ipv6 route ::/0 <IPv6-PREFIX>:2::192 200
And with carp3 line protocol being down following route is selected and
installed:
S>* ::/0 [200/0] via <IPv6-PREFIX>:2::192, wm0 <=== quagga uses
alternate route
S ::/0 [100/0] is directly connected, carp3 inactive
via <IPv6-PREFIX>::1, carp3 inactive <=== quagga
detects inactive
This is what I am expecting from the aboe configuration.
Now FRR looks different in this regard.
The FRR staticd configuration is:
ip route 0.0.0.0/0 carp3 100
ip route 0.0.0.0/0 <IPv4-NET>.65 100
ip route 0.0.0.0/0 10.0.2.192 200
ipv6 route ::/0 carp3 100
ipv6 route ::/0 <IPv6-PREFIX>::1 carp3 100
ipv6 route ::/0 <IPv6-PREFIX>:2::192 200
And FRR slect following route:
S ::/0 [200/0] via <IPv6-PREFIX>:2::192, wm0, weight 1, 00:01:01
<== frr does not use alternate route
S>* ::/0 [100/0] is directly connected, carp3 inactive, weight 1,
00:01:01<=== here frr knows thet carp3 is inactive
* via <IPv6-PREFIX>::1, carp3, weight 1, 00:01:01
<=== frr does not document/notice line protocol down.
=== also a route to <IPv6-PREFIX>::1 is installed
=== via the wm0 interface, not carp3
FRR on IPv4 the mechanism does seem to work like in quagga:
S 0.0.0.0/0 [100/0] is directly connected, carp3 inactive, weight 1,
00:00:48
via <IPv4-NET>.65, carp3 inactive, weight 1,
00:00:48 <== inactive is noticed here
S>* 0.0.0.0/0 [200/0] via 10.0.2.192, wm0, weight 1,
00:23:23 <== alternate route is selected
This violates for me the principle of least astonishment.
Multiple variants of the statics route configuration did not cause
FRR to select the route with distance 200.
Is this a bug or a feature? If it is a feature how would I have
to configure staticd then?
Best regards,
Frank Kardel