From: Andrew Lissitz \(alissitz\) (alissitz@cisco.com)
Date: Fri Oct 28 2005 - 22:31:40 GMT-3
Have you seen ipv4 neighbors be auto created and activated when config
ipv6 neighbors? This was the point of my lab, when I created ipv6
neigh, ipv4 neigh was created but not activated due to this command not
being configured.
Thanks for the link!
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Asim Mir
Sent: Friday, October 28, 2005 8:35 PM
To: Cisco certification
Cc: comserv@groupstudy.com
Subject: RE: Different Command Format on BGP routing process
On using "no bgp default ipv4-unicast":
http://www.nanog.org/mtg-0202/ppt/gottsponer-web.ppt
So, I assume it's considered best practice.
-Asim
--- "Andrew Lissitz (alissitz)" <alissitz@cisco.com>
wrote:
> Hey Yall,
>
> When I labbed this up:
>
> 1. I created ipv6 add fam and added 2 ipv6 peers 2. I then looked
> into the config and saw normal
> ipv4 peers configured
> but not activated. Peers that were created in the
> ipv6 add fam were
> also added to the regular config as Andy said, but in my case they
> were not activated.
>
> Andy had seen that the peers added to the regular
> ipv4 add fam were
> activated and passing routes, I saw that they were not activated and
> of course no nothing passed.
>
> Has anyone else labbed this up, and what did you see?
>
>
>
> -----Original Message-----
> From: Edwards, Andrew M
> [mailto:andrew.m.edwards@boeing.com]
> Sent: Wednesday, October 26, 2005 8:06 PM
> To: Andrew Lissitz (alissitz); Olopade Olorunloba; swm@emanon.com; The
> Great Ryan; Cisco certification
> Cc: comserv@groupstudy.com
> Subject: RE: Different Command Format on BGP routing process
>
> Andrew,
>
> Think about this:
>
> What if a requirement was to filter out specific prefixes on the V4
> bgp domain. Then, later you were asked to neighbor up the same mBGP
> peers in v6 address family mode.
>
> What would happen to the prefixes you so diligently filtered out in
> the
> v4 address family?
>
> -----Original Message-----
> From: Andrew Lissitz (alissitz)
> [mailto:alissitz@cisco.com]
> Sent: Wednesday, October 26, 2005 4:34 PM
> To: Olopade Olorunloba; swm@emanon.com; The Great Ryan; Cisco
> certification
> Cc: comserv@groupstudy.com
> Subject: RE: Different Command Format on BGP routing process
>
>
> Hey Yall,
>
> Please feel free to show me when you have seen other
> behavior besides
> this.
>
> If you disable ipv4 default behavior with the
> command you mention, then
> you will need to create an address family for ipv4,
> ipv6, vpnv4, etc...
> If you want to have a 'normal' ipv4 session with
> another bgp router, you
> would need to create the ipv4 address family and
> then add the neighbors
> etc... to this address family.
>
> If you use this command and turn off default ipv4
> behavior, and you
> currently have ipv4 neighbors configured, then the
> configs will be
> modified and placed under a ipv4 address fam for
> you. You do not need
> to modify the configs, just enable the no bgp
> default ipv4 command and
> you will see your config modified correctly for you.
>
>
> A question for the group ...
>
> In production or lab practices, have you seen a
> scenario / real world
> problem that required you to turn off the default
> ipv4 behavior? I can
> imagine if you have a pure vpnv4 network, and your
> PEs only speak vpnv4
> with route reflectors and PEs then you could turn
> this off... but again,
> how much memory / processing are you saving by not
> having this left @
> the default? Perhaps the bgp scanner will run
> less...? Pure ipv6
> environment perhaps?
>
> What do you think group? Have you see this command
> needed in either
> practice or production?
>
>
>
>
> -----Original Message-----
> From: Olopade Olorunloba
> [mailto:lolopade@ipnxnigeria.net]
> Sent: Wednesday, October 26, 2005 6:47 PM
> To: Andrew Lissitz (alissitz); swm@emanon.com; 'The
> Great Ryan'; 'Cisco
> certification'
> Cc: comserv@groupstudy.com
> Subject: RE: Different Command Format on BGP routing
> process
>
> On Cisco IOS where the IPv4 family does not show by
> the default, simply
> disable default IPv4 session by giving the command
> no bgp default ipv4.
> This will cause the IOS to now show the IPv4
> session, and the operation
> will be like what Scott has described here, because
> after adding a
> neighbor, you will still need to go to the IPv4
> address family to
> activate it.
>
> Regards
>
> -----Original Message-----
> From: nobody@groupstudy.com
> [mailto:nobody@groupstudy.com] On Behalf Of
> Andrew Lissitz (alissitz)
> Sent: 26 October 2005 18:18
> To: swm@emanon.com; The Great Ryan; Cisco
> certification
> Cc: comserv@groupstudy.com
> Subject: RE: Different Command Format on BGP routing
> process
>
> Nice Scott ... Thanks for the perspective on how to
> view the configs /
> address families.
>
> Cisco .. Confuses people?
>
>
> -----Original Message-----
> From: Scott Morris [mailto:swm@emanon.com]
> Sent: Wednesday, October 26, 2005 1:08 PM
> To: Andrew Lissitz (alissitz); 'The Great Ryan';
> 'Cisco certification'
> Cc: comserv@groupstudy.com
> Subject: RE: Different Command Format on BGP routing
> process
>
> No difference actually. IPv4 is the default address
> family used. Some
> newer versions of the IOS automatically put the
> "address-family ipv4"
> stuff there, I think just to avoid confusion with
> people using multiple
> families.
>
> In the R&S lab, the only one to be concerned with is
> the IPv6 address
> family. In the SP lab, you may need the vpnv4 (MPLS
> VPNs) and/or
> multicast as well.
>
> All the address-family ipv4 part does is help to
> separate things so that
> we
> (humans) are less confused. Apparantly this hasn't
> been entirely
> successful! (grin)
>
> Always remember, there are two parts to the BGP
> configuration pieces.
> Thinking of it this was (since BGP is an application
> not really an IP
> routing protocol) will help you think things
> through!
>
> There's first the "connections" piece which
> establishes your basic
> connection to your neighbor. This will include the
> neighbor statement,
> and update-source, remote-as, ebgp-multihop
> parameters and things like
> that.
>
> Then there's the RIB pieces. Each RIB is different.
> A single neighbor
>
=== message truncated ===
__________________________________
Yahoo! Mail - PC Magazine Editors' Choice 2005
http://mail.yahoo.com
This archive was generated by hypermail 2.1.4 : Sun Nov 06 2005 - 22:00:55 GMT-3