OpenBGP - iBGP peers not announcing after 3 hops

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OpenBGP - iBGP peers not announcing after 3 hops

Eduardo Meyer
Hello,

I am facing a strange behavior,

I have the following scenario

eBGP1<->iBGP1<->iBGP2<->iBGP3<->eBGP2

The very first eBGP (eBGP1) is my customer, the later (eBGP2) is my carrier
(WAN).

eBGP1 announces its network successfully to iBGP1, which announces
everything successfuly to iBGP2, but iBGP2 never announces it to iBGP3.

I have announce all and absolutely no filter.

If I set up eBGP using reserved ASN in substitution to iBGP2 and iBGP3, the
announcement just happens fine.

All received/announced networks up to iBGP2 are considered valid using
"bgpctl sh rib det nei iBGP1".

Any suggestions on what might be going wrong?




--
===========
Eduardo Meyer
pessoal: [hidden email]
profissional: [hidden email]

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Re: OpenBGP - iBGP peers not announcing after 3 hops

Florian Obser
On 02/04/2013 03:59 PM, Eduardo Meyer wrote:
> Hello,
>
> I am facing a strange behavior,
>
> I have the following scenario
>
> eBGP1<->iBGP1<->iBGP2<->iBGP3<->eBGP2

iBGP must be fully meshed, a session between iBGP1 and iBGP3 is
missing.

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Re: OpenBGP - iBGP peers not announcing after 3 hops

Eduardo Meyer
Really? It's difficult for me in this environment, do I have another option?


On Mon, Feb 4, 2013 at 1:30 PM, Florian Obser <[hidden email]> wrote:

>
>
> On 02/04/2013 03:59 PM, Eduardo Meyer wrote:
> > Hello,
> >
> > I am facing a strange behavior,
> >
> > I have the following scenario
> >
> > eBGP1<->iBGP1<->iBGP2<->iBGP3<->eBGP2
>
> iBGP must be fully meshed, a session between iBGP1 and iBGP3 is
> missing.
>



--
===========
Eduardo Meyer
pessoal: [hidden email]
profissional: [hidden email]

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Re: OpenBGP - iBGP peers not announcing after 3 hops

Andre Keller-4
Am 04.02.2013 16:32, schrieb Eduardo Meyer:
> Really? It's difficult for me in this environment, do I have another option?

add a route collector that peers with all ibgp neighbors...

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Re: OpenBGP - iBGP peers not announcing after 3 hops

Peter Hessler
In reply to this post by Eduardo Meyer
make iBGP2 a route server.

On 2013 Feb 04 (Mon) at 13:32:43 -0200 (-0200), Eduardo Meyer wrote:
:Really? It's difficult for me in this environment, do I have another option?
:
:
:On Mon, Feb 4, 2013 at 1:30 PM, Florian Obser <[hidden email]> wrote:
:
:>
:>
:> On 02/04/2013 03:59 PM, Eduardo Meyer wrote:
:> > Hello,
:> >
:> > I am facing a strange behavior,
:> >
:> > I have the following scenario
:> >
:> > eBGP1<->iBGP1<->iBGP2<->iBGP3<->eBGP2
:>
:> iBGP must be fully meshed, a session between iBGP1 and iBGP3 is
:> missing.
:>
:
:
:
:--
:===========
:Eduardo Meyer
:pessoal: [hidden email]
:profissional: [hidden email]
:

--
I don't care who does the electing as long as I get to do the nominating
                -- Boss Tweed

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Re: OpenBGP - iBGP peers not announcing after 3 hops

Eduardo Meyer
On Mon, Feb 4, 2013 at 1:36 PM, Peter Hessler <[hidden email]> wrote:

> make iBGP2 a route server.
>

Sounds promising, what are the key configurations in bgpd.conf to do so? So
I can look further.

Are we talking 'bout reflector/collector?


>
> On 2013 Feb 04 (Mon) at 13:32:43 -0200 (-0200), Eduardo Meyer wrote:
> :Really? It's difficult for me in this environment, do I have another
> option?
> :
> :
> :On Mon, Feb 4, 2013 at 1:30 PM, Florian Obser <[hidden email]> wrote:
> :
> :>
> :>
> :> On 02/04/2013 03:59 PM, Eduardo Meyer wrote:
> :> > Hello,
> :> >
> :> > I am facing a strange behavior,
> :> >
> :> > I have the following scenario
> :> >
> :> > eBGP1<->iBGP1<->iBGP2<->iBGP3<->eBGP2
> :>
> :> iBGP must be fully meshed, a session between iBGP1 and iBGP3 is
> :> missing.
> :>
> :
> :
> :
> :--
> :===========
> :Eduardo Meyer
> :pessoal: [hidden email]
> :profissional: [hidden email]
> :
>
> --
> I don't care who does the electing as long as I get to do the nominating
>                 -- Boss Tweed
>



--
===========
Eduardo Meyer
pessoal: [hidden email]
profissional: [hidden email]

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Re: OpenBGP - iBGP peers not announcing after 3 hops

Michael H Lambert
In reply to this post by Peter Hessler
On 4 Feb 2013, at 10:36, Peter Hessler wrote:

> make iBGP2 a route server.

I think this would be a route reflector since you're dealing with iBGP.

Michael

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Re: OpenBGP - iBGP peers not announcing after 3 hops

Sebastian Benoit
In reply to this post by Eduardo Meyer
Eduardo Meyer([hidden email]) on 2013.02.04 13:51:25 -0200:
> On Mon, Feb 4, 2013 at 1:36 PM, Peter Hessler <[hidden email]> wrote:
>
> > make iBGP2 a route server.
> >
>
> Sounds promising, what are the key configurations in bgpd.conf to do so? So
> I can look further.
>
> Are we talking 'bout reflector/collector?

A reflector, you need to use "route-reflector <id>" on your sessions on
iBGP2.

You might want to pick up a book on BGP.

Stuart recently recommended "BGP" by Iljitsch van Beijnum (O'Reilly), and
"BGP Design and Implementation" from Cisco will also help you along.

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Re: OpenBGP - iBGP peers not announcing after 3 hops

Stuart Henderson
In reply to this post by Eduardo Meyer
On 2013-02-04, Eduardo Meyer <[hidden email]> wrote:

>> On 02/04/2013 03:59 PM, Eduardo Meyer wrote:
>> > Hello,
>> >
>> > I am facing a strange behavior,
>> >
>> > I have the following scenario
>> >
>> > eBGP1<->iBGP1<->iBGP2<->iBGP3<->eBGP2
>>
>> iBGP must be fully meshed, a session between iBGP1 and iBGP3 is
>> missing.
>
> Really? It's difficult for me in this environment, do I have another option?

This doesn't mean that they need to be directly connected; iBGP sessions
can be run over multiple hops by default. It just means you need neighbour
configs for 1<>2, 1<>3, 2<>3.

You could use a route reflector as others suggested but it's a bit
much for this setup imo; it will be a critical part of the network so
you'll probably want a redundant pair. These come into their own when the
number of routers goes up.

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Re: OpenBGP - iBGP peers not announcing after 3 hops

Eduardo Meyer
On Tue, Feb 5, 2013 at 8:34 AM, Stuart Henderson <[hidden email]>wrote:

> On 2013-02-04, Eduardo Meyer <[hidden email]> wrote:
> >> On 02/04/2013 03:59 PM, Eduardo Meyer wrote:
> >> > Hello,
> >> >
> >> > I am facing a strange behavior,
> >> >
> >> > I have the following scenario
> >> >
> >> > eBGP1<->iBGP1<->iBGP2<->iBGP3<->eBGP2
> >>
> >> iBGP must be fully meshed, a session between iBGP1 and iBGP3 is
> >> missing.
> >
> > Really? It's difficult for me in this environment, do I have another
> option?
>
> This doesn't mean that they need to be directly connected; iBGP sessions
> can be run over multiple hops by default. It just means you need neighbour
> configs for 1<>2, 1<>3, 2<>3.
>
> You could use a route reflector as others suggested but it's a bit
> much for this setup imo; it will be a critical part of the network so
> you'll probably want a redundant pair. These come into their own when the
> number of routers goes up.
>
>
Yeah, you are all right,

multihop peering just did fine; as well as route-reflector for iBGP group
just worked fine;

yeah I need to read some bgp basics; usually I tend to learn by experience
and this is when such a great community comes to hand; I learn more with
you than books but certainly some bgp theory will be on my reading list for
the weekends;

thanks veryone who kindly replied, I will think about the expected growing
rate of the network and complexity to decide if I go with peering or
route-reflector for this environment;

--
===========
Eduardo Meyer
pessoal: [hidden email]
profissional: [hidden email]

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Re: OpenBGP - iBGP peers not announcing after 3 hops

Claudio Jeker
In reply to this post by Stuart Henderson
On Tue, Feb 05, 2013 at 10:34:02AM +0000, Stuart Henderson wrote:

> On 2013-02-04, Eduardo Meyer <[hidden email]> wrote:
> >> On 02/04/2013 03:59 PM, Eduardo Meyer wrote:
> >> > Hello,
> >> >
> >> > I am facing a strange behavior,
> >> >
> >> > I have the following scenario
> >> >
> >> > eBGP1<->iBGP1<->iBGP2<->iBGP3<->eBGP2
> >>
> >> iBGP must be fully meshed, a session between iBGP1 and iBGP3 is
> >> missing.
> >
> > Really? It's difficult for me in this environment, do I have another option?
>
> This doesn't mean that they need to be directly connected; iBGP sessions
> can be run over multiple hops by default. It just means you need neighbour
> configs for 1<>2, 1<>3, 2<>3.
>
> You could use a route reflector as others suggested but it's a bit
> much for this setup imo; it will be a critical part of the network so
> you'll probably want a redundant pair. These come into their own when the
> number of routers goes up.

It should be possible to make all routers route-reflectors and not do a full
mesh but route-reflector setups are not inherently stable. In some
setups they can result in a unstable network. Especially when adding
redundancies to setups (by additional RRs or additional iBGP links) it is
possible to end up with a not converging network which is fun fun fun...

In general if you have less than a handfull bgp router us a full mesh.
The pain of fiddeling with RR is not worth the few sessions you save.
--
:wq Claudio