Home
Reading
Searching
Subscribe
Sponsors
Statistics
Posting
Contact
Spam
Lists
Links
About
Hosting
Filtering
Features Download
Marketing
Archives
FAQ
Blog
 
Gmane
From: Joachim Nilsson <troglobit <at> gmail.com>
Subject: [quagga-dev 9389] Re: OSPF: Problem with route distribution when restarting ospfd, since 0.99.18
Newsgroups: gmane.network.quagga.devel
Date: Wednesday 30th May 2012 12:12:13 UTC (over 4 years ago)
Hi again,

the fix/revert discussed below is available for cherry-picking from
my GitHub repository, branch westermo/ospfd-fixes

https://github.com/troglobit/quagga/commits/westermo/ospfd-fixes

Regards
  /Joachim

On 05/28/2012 02:00 PM, Joachim Nilsson wrote:
> Hi,
>
> we've been looking further into this issue, done some bisecting
> and found the root cause, or change, that cause the problems
> we see. (Please see the full report in the original mail for details)
>
> http://git.savannah.gnu.org/gitweb/?p=quagga.git;a=commit;h=02d942c9d4afabf04bd781f0e1e5e8aa36945df2
>
> This commit causes the problem. It introduces a #define for
> MaxAge removal used by ospf_lsa.c:ospf_maxage_lsa_remover().
>
> #define OSFP_LSA_MAXAGE_REMOVE_DELAY_DEFAULT 60
>
> This value used to be hard coded to 2 and if I change this back to
> 2 ... yes, that's all I need to do, then our problem disappears!
>
> The reason for the change is the discussion on quagga-dev:4132
> about a bug in long delay networks.
>
> http://lists.quagga.net/pipermail/quagga-dev/2006-May/004133.html
>
> I'm still not at all up to speed on how the inner workings of OSPF
> should behave, but is this perhaps related to Step 8 of Section 13,
> as discussed in "G.1 Flooding Modifications" of RFC2328?
>
> http://tools.ietf.org/html/rfc2328#section-13
>
> I may be mixing the cards up now, but Cisco seem to have some
> other form of counter measures for this in their
>
>     interface  
>         ip ospf flood-reduction
>
> http://www.cisco.com/en/US/docs/ios/12_1t/12_1t2/feature/guide/dt_ospff.html
>
> Anyone else with input on this?
>
> Regards
>  /Joachim
>
> On 05/14/2012 05:50 PM, Joachim Nilsson wrote:
>> We've seen OSPF issues when reconfiguring ospfd at runtime in our
>> testbeds at Westermo.  By editing its config file and restarting ospfd
>> we see problems with route distribution.
>>
>> Laptop setup, very simple. Two areas, one RIP network with loopback
>> /32 nets on R1 and R4. Most of the time it works, but sometimes when
>> we restart ospfd on R2 the edge router R1 never gets any routes.
>>   ______
>> |      |---| 66.66.66.66/32
>> |      |
>> |  R1  |
>> |      |
>> |______|
>>     |.1
>>     |
>>     | 172.12.0.0/24
>>     | Area 2
>>     |
>>     |.2
>>   ______
>> |      |
>> |      |
>> |  R2  |
>> |      |
>> |______|
>>     |.1
>>     |
>>     | 172.10.0.0/24
>>     | Area 0
>>     |
>>     |.2
>>   ______
>> |      |
>> | ASBR |
>> |  R3  |
>> |      |
>> |______|
>>     |.1
>>     |
>>     | 10.1.0.0/24
>>     |   RIP
>>     |.2
>>   ______
>> |      |---| 14.0.0.1/32
>> |      |---| 15.0.0.1/32
>> |  R4  |---| 16.0.0.1/32
>> |      |
>> |______|
>>
>> In reproducing the bug we restart ospfd on R2 by pressing Ctrl-C
>>
>> while [ 1 ]; do
>>      sudo ./ospfd/ospfd -u root -g root -f ../ospfd.conf
>>      sleep 1;
>> done
>>
>> Results ...
>>
>> 0.99.17:
>>      - Stable as a rock!
>>
>> 0.99.18 - Git:
>>      - Sometimes loss of 66-network in R3 and R4
>>      - Loss of all RIP nets in R1
>>
>> Sadly we haven't yet had the time to try and figure out where the bug
>> is located.  However, we noticed that there was quite an overhaul of
>> the LSA refresh logic in 0.99.18.
>
 
CD: 3ms