inter-domain link recovery

["Chengchen Hu" <huc () ieee org>]

Hi, folks

I find that the link recovery is sometimes very slow when failure occures between different ASes. The outage may last 
hours. In such cases, it seems that the automatic recovery of BGP-like protocol fails and the repair is took over 
manually. 

We should still remember the taiwan earthquake in Dec. 2006 which damaged almost all the submarine cables. The network 
condition was quit terrible in the following a few days. One may need minutes to load a web page in US from Asia. 
However, two main cables luckly escaped damage. Furthermore, we actually have more routing paths, e.g., from Asia and 
Europe over the trans-Russia networks of Rostelecom and TransTeleCom. With these redundent path, the condition should 
not be that horrible.

And here is what I'd like to disscuss with you, especially the network operators,
1. Why BGP-like protocol failed to recover the path sometimes? Is it mainly because the policy setting by the ISP and 
network operators?

2. What is the actions a network operator will take when such failures occures? Is it the case like that, 1)to find (a) 
alternative path(s); 2)negotiate with other ISP if need; 3)modify the policy and reroute the traffic. Which actions may 
be time consuming?

3. There may be more than one alternative paths and what is the criterion for the network operator to finally select 
one or some of them?

4. what infomation is required for a network operator to find the new route?  

Thank you.
        
C. Hu