$Protocol State changed to up

[Bartosz Radwan]

Hi there

We're using bird as bgp router, have several upstram sessions established.

Recently, I've switched on states logging using

debug protocols {states};

I've noticed one of the bgp protocols emits State changed to up events 
on regular time basis:

2015-01-30T07:06:11+01:00 BGP-1 IX_RS2: State changed to up
2015-01-31T07:06:14+01:00 BGP-1 IX_RS2: State changed to up
2015-02-01T07:06:11+01:00 BGP-1 IX_RS2: State changed to up
2015-02-02T07:06:12+01:00 BGP-1 IX_RS2: State changed to up

One and just one upstram. How should i interpret this?

What is the equivalent of "State changed to up" in BGP finite state machine?

Forgive me my lazyness, the answer is in the bird source for sure, but 
haven't enough time or knowledge to find out.

Thanks in advance.

-- 
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
Bartosz Radwan