[afnog] afnog Digest, Vol 49, Issue 11

Fri Apr 11 17:34:36 UTC 2008

    CE1---------- -----------CE2
    |                                |
    |                                |
    |                                |
    |                                |
   SP1                          SP2

CE1-----EBGP-------SP1 ( /23)
CE2----EBGP -------SP2 (/24)

CE1----IBGP/IGP-----CE2----

CE1
config t
ip prefix-list test permit x.x.x.x/24
ip prefix-list test permit x.x.x.x/24

route-map <blah> permit 10
match ip address prefix-list test
set as-path prepend XXX.XXX xxxx:xxxx
route-map <blah> permit 20

then apply the route-map to EBGP

config t
router bgp xxx
address-family ipv4
neighrbor SP1 route-map <blah> out
end

CE2
config t
ip prefix-list test permit x.x.x.x/23

route-map <blah> permit 10
match ip address prefix-list test
set as-path prepend xxx:xx xxx:xxx
route-map <blah> permit 20

config t
router bgp xxx
address-family ipv4
neighrbor SP2 route-map <blah> out
end

Now keep in mind this ONLY controller your return path, as you know BGP path
control works reverse, meaning your outbound policy control how people see
you from the world which in turn influence the return traffic back to you.
Now let's assume you want all /24 to go CE2 and all /23 to go CE1.

You can make this to work in different ways. Please tell us more how the two
CE routers are connected? are they on the same building? Do they connect
to each other? is there HSRP configuration? Do they share the same Switch to
the LAN? Is that Switch part of the IBGP or IGP? What kind of IGP protocol
are you running?

Thanks,

On Fri, Apr 11, 2008 at 8:00 AM, <afnog-request at afnog.org> wrote:

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> Today's Topics:
>
>   1. Re:  reverse dns implications (Phil Regnauld)
>   2.  bgp-load sharing (brunild KODJO)
>   3. Re:  bgp-load sharing (Peter Nyamukusa)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Fri, 11 Apr 2008 13:03:03 +0200
> From: Phil Regnauld <regnauld at x0.dk>
> Subject: Re: [afnog] reverse dns implications
> To: Maina M Noah <ncmaina2001 at yahoo.com>
> Cc: afnog at afnog.org
> Message-ID: <20080411110303.GB52185 at macbook.catpipe.net>
> Content-Type: text/plain; charset=us-ascii
>
> Maina M Noah (ncmaina2001) writes:
> > Customer Mail servers would require the reverse DNS in case the ISP
> allocates the customer a public IP address for their local mail server.This
> not only helps combat spam but also makes it easier for the Mail host to be
> found by other domains, other wise mails would be rejected by those other
> domains the mail server sends email to.
>
>        That is, assuming that:
>
>        a) there's enough customers
>        b) sufficienly many of them know about reverse DNS
>        c) there is enough of a competitive market for the ISP to *care*
>
> > That is how we do it as an ISP and our clients
> > are very much happy.
>
>        Good to hear :)
>
>
>
> ------------------------------
>
> Message: 2
> Date: Fri, 11 Apr 2008 06:15:01 -0500
> From: "brunild KODJO" <brhunild at gmail.com>
> Subject: [afnog] bgp-load sharing
> To: afnog at afnog.org
> Message-ID:
>        <e28fb1410804110415t7a4db180x5223eba7a80233cf at mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
>  Hi,
>
> I have a problem configuring a kind of load sharing.
>
> I have a vsat connection with an ISP and 2 downlink via DVB.
>
> I have split my network address space /22 in 1 /23 and 2 /24.
>
> I would like to downlink on /24 on a dvb and the rest of the traffic to
> the
> other dvb.
>
> Added to that I would like when a dvb goes down to have the traffic to use
> the available downlink.
>
> I have bgp with each peer on their AS number
>
> Use ebgp next hot with each peers
>
> set as multipath
>
> and then do route map wih each peer but I put a long AS PATH to the non
> prefered route.
>
> But it is not working.
>
> Can you help?
>
> Brunild
> --
> Brunild Kodjo
> -------------- next part --------------
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> ------------------------------
>
> Message: 3
> Date: Fri, 11 Apr 2008 14:22:35 +0300
> From: "Peter Nyamukusa" <petern at africaonline.co.tz>
> Subject: Re: [afnog] bgp-load sharing
> To: "'brunild KODJO'" <brhunild at gmail.com>,     <afnog at afnog.org>
> Message-ID: <mailman.4.1207915201.99714.afnog at afnog.org>
> Content-Type: text/plain;       charset="iso-8859-1"
>
> ________________________________________
> >From: afnog-bounces at afnog.org [mailto:afnog-bounces at afnog.org] On Behalf
> Of
> >brunild KODJO
> >Sent: Friday, April 11, 2008 1:36 PM
> >To: afnog at afnog.org
> >Subject: [afnog] bgp-load sharing
> >
> >
> >Hi,
> >?
> >I have a problem configuring a kind of load sharing.
> >?
> >I have a vsat connection with an ISP and 2 downlink via DVB.
> >?
> >I have split my network address space /22 in 1 /23 and 2 /24.
> >?
> >I would like to downlink on /24 on a dvb and the rest of the traffic to
> the
> >other dvb.
> Hi Brunild,
>
> I would suggest that you announce the 2 /24 to you 1st DVB satellite
> provider and then also announce a pre-pended /22 as well
> Then announce the /23 to the second DVB satellite provide as well as a
> pre-pended /22.
> The most specific routes are chosen which means if DVB 1 is up the /24
> routes are available and routing will prefer the /24 but if DVB 1 goes
> down
> the routes will be removed from the internet routing tables but will be
> matched in the /22 prefix from DVB 2 and therefore will use the other
> link.
> This is true for the reverse on DVB 2
>
> You also need to make sure you have some route objects in ripe or afrinic
> for the blocks you are announcing as I have seen many people make that
> mistake.
>
> If you want to be more specific you can give us a sample of your configs
> and
> will be happy to assist
>
> HTH
>
> Cheers,
>
> Peter.
>
>
> >?
> >Added to that I would like when a dvb goes down to have the traffic to
> use
> >the available downlink.
> >?
> >I have bgp with each peer on their AS number
> >?
> >Use ebgp next hot with each peers
> >?
> >set as multipath
> >?
> >and then do route map wih each peer but I put a long AS PATH to the non
> >prefered route.
> >?
> >But it is not working.
> >?
> >Can you help?
> >?
> >Brunild
> >--
> >Brunild Kodjo
>
>
>
>
> ------------------------------
>
> _______________________________________________
> afnog mailing list
>
> End of afnog Digest, Vol 49, Issue 11
> *************************************
>

-- 
Liban Mohamed
Global One Solution
www.globalonesolutions.net
malabow at gmail.com
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