On Aug 15, 2007, at 12:06 AM, Chengchen Hu wrote:
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?
Why do you think BGP was supposed to find the remaining path? Is it
possible that the remaining fibers were not owned or leased by the
networks in question? Or are you suggesting that any capacity should
be available to anyone who "needs" it, whether they pay or not?
BGP cannot find a path that the business rules forbid.
--
TTFN,
patrick
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
