On Mon, Dec 05, 2016 at 04:20:23PM +0000, Wei Huang wrote:

When I set my ospf interface eth1's address to be 10.2.1.2/30, neighbor router ethernet interface IP address to be 10.2.1.1/30, the neighbor shows it's PTP type:

bird> sh ospf neighbors ospf_rdomain_0: Router ID Pri State DTime Interface Router IP 172.16.20.76 1 Full/PtP 00:35 vni-0 10.2.1.1

If I change the interfaces' IP address to be 10.2.1.x/24 or I force interface type to be bcast in Bird's ospf config, it shows as

bird> sh ospf neighbors ospf_rdomain_0: Router ID Pri State DTime Interface Router IP 172.16.20.76 1 Full/DR 00:35 vni-0 10.2.1.1

My question is how does Bird detect the connected network type?

Hi Generally based on iface multicast ability and address range: multicast, big range -> Type Broacast multicast, small range -> Type PtP no multicast, big range -> Type NBMA no multicast, small range -> Type PtMP Where small range is prefix length 30, 31 or 32. Other combinations are possible, but PtP and Broadcast require multicast ability; Broadcast and NBMA require regular prefix (prefix length < 32). -- Elen sila lumenn' omentielvo Ondrej 'Santiago' Zajicek (email: santiago@crfreenet.org) OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net) "To err is human -- to blame it on a computer is even more so."