From: Brian Dennis (bdennis@internetworkexpert.com)
Date: Mon Jul 26 2004 - 21:33:11 GMT-3
Here is the logic behind the keepalive issue:
When the interface is being used for DDR and is not connected to
the remote router, the ISDN interface needs to be in the up/up(spoofing)
state to ensure that packets can be routed out of the ISDN interface
which will in turn trigger a call (dialer-list permitting). If
keepalives were enabled, the lack of the remote router not being
connected would cause the keepalives to be missed and in turn the ISDN
interface would switch to the up/down state. This would cause the
connected route for the ISDN interface to be removed from the routing
table. If this connected route is removed, the router can not route
packets across the ISDN interface to the remote router and in turn will
never make a call.
With a leased line configuration, under normal circumstances,
the interface will always be connected to the remote router. Since the
remote router is always connected and is able to respond to the
keepalives, the IOS permits keepalives to be enabled.
Brian Dennis, CCIE #2210 (R&S/ISP-Dial/Security)
bdennis@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987
Direct: 775-745-6404 (Outside the US and Canada)
-----Original Message-----
From: ccie2be [mailto:ccie2be@nyc.rr.com]
Sent: Monday, July 26, 2004 12:38 PM
To: Brian Dennis; jvillavalls@yahoo.com; ccielab@groupstudy.com
Subject: Re: keepalive on BRI
Thanks Brian.
But, does the output from your earlier post mean that keepalives are NOT
a
legit characteristic to set on a BRI interface (without the leased-line
command)? And, if so, shouldn't the IOS complain if someone tries to
set a
keepalive value?
Thanks again.
----- Original Message -----
From: "Brian Dennis" <bdennis@internetworkexpert.com>
To: "ccie2be" <ccie2be@nyc.rr.com>; <jvillavalls@yahoo.com>;
<ccielab@groupstudy.com>
Sent: Monday, July 26, 2004 3:29 PM
Subject: RE: keepalive on BRI
Keepalives under the ISDN interface will become enabled if you issue the
"isdn leased-line <interface>" command.
Rack1R4(config)#do sho int br0/0 | in Keep
Rack1R4(config)#
Rack1R4(config)#isdn leased-line br0/0
Rack1R4(config)#do sho int br0/0 | in Keep
Keepalive set (10 sec)
Rack1R4(config)#int br0/0
Rack1R4(config-if)#keep 30
Rack1R4(config-if)#do sho int br0/0 | in Keep
Keepalive set (30 sec)
Rack1R4(config-if)#
Brian Dennis, CCIE #2210 (R&S/ISP-Dial/Security)
bdennis@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987
Direct: 775-745-6404 (Outside the US and Canada)
-----Original Message-----
From: ccie2be [mailto:ccie2be@nyc.rr.com]
Sent: Monday, July 26, 2004 12:24 PM
To: Brian Dennis; jvillavalls@yahoo.com; ccielab@groupstudy.com
Subject: Re: keepalive on BRI
Hey Brian,
I see the output below but I don't why nothing shows up for the bri0/0
interface. What does that mean?
Thanks
----- Original Message -----
From: "Brian Dennis" <bdennis@internetworkexpert.com>
To: <jvillavalls@yahoo.com>; <ccielab@groupstudy.com>
Sent: Monday, July 26, 2004 1:56 PM
Subject: RE: keepalive on BRI
> Have you tried to apply the command to a BRI interface to see if it
even
> has any affect?
>
> Rack1R4(config-if)#int s0/0
> Rack1R4(config-if)#keep 30
> Rack1R4(config-if)#do sho int s0/0 | in Keep
> Keepalive set (30 sec)
> Rack1R4(config-if)#no keep
> Rack1R4(config-if)#do sho int s0/0 | in Keep
> Keepalive not set
> Rack1R4(config-if)#int br0/0
> Rack1R4(config-if)#keep 30
> Rack1R4(config-if)#do sho int bri0/0 | in Keep
> Rack1R4(config-if)#
> Rack1R4(config-if)#no keep
> Rack1R4(config-if)#do sho int bri0/0 | in Keep
> Rack1R4(config-if)#
>
> Brian Dennis, CCIE #2210 (R&S/ISP-Dial/Security)
> bdennis@internetworkexpert.com
> Internetwork Expert, Inc.
> http://www.InternetworkExpert.com
> Toll Free: 877-224-8987
> Direct: 775-745-6404 (Outside the US and Canada)
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> jvillavalls@yahoo.com
> Sent: Monday, July 26, 2004 8:52 AM
> To: ccielab@groupstudy.com
> Subject: keepalive on BRI
>
> Hi,
> Anyone knows why or when should I deactivate the keepalives on BRIs??
>
> examples:
> int bri0/0
> no keepalive
>
>
> thanks.
>
>
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