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Hi, I notice a possible bug of Batfish. That is, when a BgpProcess is multipathIbgp enabled but multipathEbgp disabled (implying multipath enabled, since multipath = multipathIbgp || multipathEbgp), given two equal-cost EBGP routes LEARNED from neighbors, the corresponding BgpRoutingProcess's _ebgpv4Rib will insert only one of them into its RibTree since it is multipath disabled, while its _bgpv4Rib will insert both of the routes into its RibTree since it is multipath enabled.
You can use the following code to find the inconsistency:
// set up
NetworkFactory nf = new NetworkFactory();
Configuration c =
nf.configurationBuilder()
.setConfigurationFormat(ConfigurationFormat.CISCO_IOS)
.setHostname("c1")
.build();
Vrf vrf = nf.vrfBuilder().setOwner(c).setName(DEFAULT_VRF_NAME).build();
BgpProcess bgpProcess = BgpProcess.testBgpProcess(Ip.ZERO);
bgpProcess.setMultipathIbgp(true);
bgpProcess.setMultipathEbgp(false);
vrf.setBgpProcess(bgpProcess);
Rib mainRib = new Rib();
mainRib.mergeRouteGetDelta(
new AnnotatedRoute<>(
StaticRoute.testBuilder().setNetwork(Prefix.parse("70.0.0.0/24")).build(),
DEFAULT_VRF_NAME));
mainRib.mergeRouteGetDelta(
new AnnotatedRoute<>(
StaticRoute.testBuilder().setNetwork(Prefix.parse("60.0.0.0/24")).build(),
DEFAULT_VRF_NAME));
BgpRoutingProcess routingProcess =
new BgpRoutingProcess(
bgpProcess, c, DEFAULT_VRF_NAME, mainRib, BgpTopology.EMPTY, new PrefixTracer());
// init two equal-cost EBGP routes learned from neighbors
Prefix pfx = Prefix.parse("10.0.1.0/24");
Bgpv4Route r1 =
Bgpv4Route.testBuilder()
.setNetwork(pfx)
.setNextHopIp(Ip.parse("70.0.0.1"))
.setOriginMechanism(OriginMechanism.LEARNED)
.setReceivedFrom(ReceivedFromIp.of(Ip.parse("70.0.0.1")))
.build();
Bgpv4Route r2 =
Bgpv4Route.testBuilder()
.setNetwork(pfx)
.setNextHopIp(Ip.parse("60.0.0.1"))
.setOriginMechanism(OriginMechanism.LEARNED)
.setReceivedFrom(ReceivedFromIp.of(Ip.parse("60.0.0.1")))
.build();
// insert r1 into _bgpv4Rib and _ebgpv4Rib, the test will success
routingProcess._bgpv4Rib.mergeRouteGetDelta(r1);
routingProcess._ebgpv4Rib.mergeRouteGetDelta(r1);
assertEquals(routingProcess._bgpv4Rib.getRoutes(pfx), routingProcess._ebgpv4Rib.getRoutes(pfx));
// insert r2 into _bgpv4Rib and _ebgpv4Rib, the test will fail
routingProcess._bgpv4Rib.mergeRouteGetDelta(r2);
routingProcess._ebgpv4Rib.mergeRouteGetDelta(r2);
assertEquals(routingProcess._bgpv4Rib.getRoutes(pfx), routingProcess._ebgpv4Rib.getRoutes(pfx));
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