Re: BGP Convergence

Sorry ... I should also note, if you have a lot of RRs with a lot of routes,
you may consider increasing the update-delay. This will give the router
more time to receive all the updates before running the best path calc. For
large networks this can help quite a bit.

On Tue, Jun 30, 2009 at 6:46 PM, ALL From_NJ <all.from.nj_at_gmail.com> wrote:

> Next hop tracking will greatly speed things up ...
>
> What about BFD? Platform support is sketchy ... but on most of the
> software platforms you can probably run this. You can also tune the timers
> some but ... this is not always preferred since it can be taxing on the
> CPU. If you can run BFD, this is better than changing the timers. Is your
> question related to production or lab?
>
> HTH,
>
> Andrew Lee Lissitz
>
>
> On Tue, Jun 30, 2009 at 1:59 PM, kaushalccie patel <kaushalccie_at_gmail.com>wrote:
>
>> I went through both options, And found following diff..
>>
>>
>> http://www.cisco.com/en/US/partner/docs/ios/iproute/command/reference/irp_bgp3.html#wp1013842
>> *neighbor** **ip-address** *fall-over [*bfd* | *route-map* *map-name*]
>> monitor the peering session of a specified neighbor for adjacency changes
>> and to deactivate the peering session,
>> Adjacency changes are detected, and terminated peering sessions are
>> deactivated in between the default or configured BGP scanning interval.
>>
>> By default, the BGP scanner is used to poll the RIB for this information
>> every 60 seconds. During the 60 second time period between scan cycles,
>> Interior Gateway Protocol (IGP) instability or other network failures can
>> cause black holes and routing loops to temporarily form.
>>
>>
>> *bgp fast-external-fallover *
>> for BGP peering sessions with directly connected external peers
>> The session is immediately reset if link goes down. Only directly
>> connected
>> peering sessions are supported.
>>
>>
>> http://www.cisco.com/en/US/partner/docs/ios/iproute/command/reference/irp_bgp2.html#wp1015842
>> *ip bgp fast-external-fallover* [*permit *| *deny*]
>> per-interface fast external fallover
>> overriding the global configuration
>>
>> If we compare both the option,
>> In Terms of Faster Detection - Link Failures will be detected first and
>> then
>> BGP Session failure
>> But - bgp fast-external-fallover - supports only directly connected
>> neighbors.
>>
>> HTH
>> -Kaushal
>>
>>
>> Blogs and organic groups at http://www.ccie.net
>>
>> _______________________________________________________________________
>> Subscription information may be found at:
>> http://www.groupstudy.com/list/CCIELab.html
>>
>>
>>
>>
>>
>>
>>
>>
>
>
> --
> Andrew Lee Lissitz
> all.from.nj_at_gmail.com
>

-- 
Andrew Lee Lissitz
all.from.nj_at_gmail.com
Blogs and organic groups at http://www.ccie.net