[Xorp-hackers] How OSPF control Xrl requests at the same time?

[Nguyen Van Nam]

Hi all,
Because eventloop can run only once at a time, so I have a question, how OSPF handle when there are many Xrl request arriving at the same time??
Thanks so much to explain me?
Nguyen Van Nam



----- Original Message ----
From: Bruce M Simpson <bms at incunabulum.net>
To: Nguyen Van Nam <van_nam_78 at yahoo.com>
Cc: XORP DEVELOPERS <xorp-hackers at icir.org>
Sent: Monday, August 4, 2008 12:05:45 AM
Subject: Re: [Xorp-hackers] Conflict  between processes, how to avoid?

Nguyen Van Nam wrote:
> Hi all,
> Thank you so much for your answers.
> In fact, i have implemented a XRL client interface to notify LSDB change.
> But I have encountered an error when I called another Xrl request to 
> set interface cost, because this one cause the LSDB to be changed
> immediately so at the same time there are 2 processes running. In your 
> experiences , how to avoid this?

XRLs can only be processed one at a time by any XORP process, as they 
are all single threaded.

How exactly is the race condition manifesting in your program, and how 
is this a problem? It would be helpful for others if you point out 
exactly which error(s) you're seeing.

It is not going to be possible to avoid having the Lsa database change 
from underneath the xorp_ospf process, obviously because setting the 
interface cost changes the cost of Lsas (and their corresponding routing 
table entries) which transit that interface.

thanks
BMS



      
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