Re: [savi] Does the improvement to IGP algorithms solve the false positive of uRPF?

Bingyang LIU <bjornliu@gmail.com> Sat, 07 January 2012 06:17 UTC

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Date: Sat, 07 Jan 2012 01:17:21 -0500
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From: Bingyang LIU <bjornliu@gmail.com>
To: "Joel M. Halpern" <jmh@joelhalpern.com>
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Subject: Re: [savi] Does the improvement to IGP algorithms solve the false positive of uRPF?
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yes, but should we improve or extend the IGPs to make uRPF work better? Or
we need some other methods for intra-domain anti-spoofing?

On Sat, Jan 7, 2012 at 12:55 AM, Joel M. Halpern <jmh@joelhalpern.com>wrote:

> Attempting to improve the convergence times of routing protocols seems to
> me to be clearly out of scope for SAVI.
>
> Yours,
> Joel
>
>
> On 1/6/2012 11:50 PM, Bingyang LIU wrote:
>
>> Hi all,
>>
>> In IETF82, there was a discussion about SAVI beyond the first hop,
>> especially the problems of uRPF. In the intra-domain scenario,
>> asymmetric routing and fast reroute can cause the false positive of uRPF.
>>
>>
>> A possible solution is to improve the IGP algorithm (link-state and
>> distance-vector), so that the routers can better exchange and have
>> sufficient information to enforce uRPF without false positive.
>>
>> However, in case of static routing configured on some routers, better
>> exchanging link-state or distance-vector information couldn't help with
>> the correctness of uRPF. So essentially, what we should do is to
>> exchange the route decision that has already been made on each router,
>> so that each router has full information to enforce uRPF correctly.
>>
>> In another dimension, the information should be updated frequently,
>> otherwise, fast re-route may cause the information on some routers
>> incomplete.
>>
>> best
>> Bingyang
>> --
>> Bingyang Liu
>> Network Architecture Lab, Network Center,Tsinghua Univ.
>> Beijing, China
>> Home Page: http://netarchlab.tsinghua.**edu.cn/~liuby<http://netarchlab.tsinghua.edu.cn/~liuby>
>>
>>
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>


-- 
Bingyang Liu
Network Architecture Lab, Network Center,Tsinghua Univ.
Beijing, China
Home Page: http://netarchlab.tsinghua.edu.cn/~liuby