Here is explanation ----
Whenever there is a change in the policy, the BGP session has to be cleared
for the new policy to
take effect. Clearing a BGP session causes cache invalidation and results in
a tremendous impact on
the operation of networks.
Soft reconfiguration allows policies to be configured and activated without
clearing the BGP session.
Soft reconfiguration is recommended; it is done on a per-neighbor basis.
. When soft reconfiguration is used to generate inbound updates from a
neighbor, it is called
inbound soft reconfiguration.
. When soft reconfiguration is used to send a new set of updates to a
neighbor, it is called outbound
soft reconfiguration.
Performing inbound reconfiguration enables the new inbound policy to take
effect. Performing
outbound reconfiguration causes the newlocal outbound policy take effect
without resetting the BGP
session. As a new set of updates is sent during outbound policy
reconfiguration, a new inbound
policy of the neighbor can also take effect.
In order to generate new inbound updates without resetting the BGP session,
the local BGP speaker
should store all the received updates without modification, regardless of
whether it is accepted or
denied by the current inbound policy. This is memory intensive and should be
avoided. On the other
hand, outbound soft reconfiguration does not have any memory overhead. One
could trigger an
outbound reconfiguration in the other side of the BGP session to make the
new inbound policy take
effect.
To allowinbound reconfiguration, BGP should be configured to store all
received updates. Outbound
reconfiguration does not require preconfiguration.
You can configure the Cisco IOS software to start storing received updates,
which is required for
inbound BGP soft reconfiguration. Outbound reconfiguration does not require
inbound soft
reconfiguration to be enabled.
To configure BGP soft configuration, use the following command in router
configuration mode:
neighbor {ip-address | peer-group-name} soft-reconfiguration
Hope this answers your query
Thanks
Thangavel
----- Original Message -----
From: jason yee <[EMAIL PROTECTED]>
To: thangs <[EMAIL PROTECTED]>; ElephantChild <[EMAIL PROTECTED]>; whatshakin
<[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>
Sent: Tuesday, October 24, 2000 12:43 PM
Subject: Re: route table
> really I did not know about this , please elaborate
>
> thanks
>
> suaveguru
> --- thangs <[EMAIL PROTECTED]> wrote:
> > I feel that it is not advisable to use soft in as
> > an argument ,coz your
> > router might end up with a memory crunch......
> >
> > Thanks
> > Thangavel
> > ----- Original Message -----
> > From: jason yee <[EMAIL PROTECTED]>
> > To: ElephantChild <[EMAIL PROTECTED]>; whatshakin
> > <[EMAIL PROTECTED]>
> > Cc: <[EMAIL PROTECTED]>
> > Sent: Tuesday, October 24, 2000 8:03 AM
> > Subject: Re: route table
> >
> >
> > > alternatively you can try clear ip bgp <neigh
> > addr>
> > > soft in /out to just update the bgp table and not
> > > flush all of them
> > >
> > >
> > > suaveguru
> > > --- ElephantChild <[EMAIL PROTECTED]> wrote:
> > > > On Sun, 1 Oct 2000, whatshakin wrote:
> > > >
> > > > > clear ip bgp *
> > > > >
> > > > > Don't do this on a production network during
> > > > business hours!
> > > >
> > > > On a production network running BGP, business
> > hours
> > > > tend to be 7/24.
> > > >
> > > > > ----- Original Message -----
> > > > > From: Raymond Mak <[EMAIL PROTECTED]>
> > > > > >
> > > > > > Would you tell me how to flush the bgp
> > routing
> > > > table to make it learn
> > > > > > again?
> > > >
> > > > --
> > > > Bungee jumping and skydiving are for wimps. If
> > you
> > > > want to experience
> > > > true gut-wrenching terror, have children.
> > --Dusty
> > > > Rhoades.
> > > >
> > > > **NOTE: New CCNA/CCDA List has been formed. For
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