Re: Comments ......Ethernet Switch at IXP

["Mark Tinka" <mtinka@sanyutel.com>]

Well, there you have it.. justification for the use of an Ethernet Switch at
the IXP as opposed to a router. Comment.

Regards,

Mark Tinka
Network Administrator
Sanyutel Uganda
8/10 Metropole House
Entebbe Road
Kampala, Uganda
Tel:  +256-41-342269
Fax:  +256-41-341470
E-mail:  mtinka@sanyutel.com
            tinka@sanyuafrica.com
Web:   www.sanyutel.com
            www.sanyuafrica.com
----- Original Message -----
From: "Barry Raveendran Greene" <bgreene@cisco.com>
To: "Randy Bush" <randy@psg.com>; "Lunghabo James" <lunghabo@afsat.com>
Cc: <techies@uixp.co.ug>; "Abha Ahuja" <ahuja@umich.edu>
Sent: Friday, May 04, 2001 5:06 PM
Subject: RE: Comments ......


> Hello Everyone,
>
> Rob just added me to the list. Looks like I missed some messages to put
this
> into complete context.
>
> On the general topic of L3 (a router is the IXP medium) or a L2 (a switch
is
> the IXP Medium) type of IXP - then I vote with L2. In fact, I do not
> consider a L3 IXP - with a router as the IXP medium - as a viable IXP
model
> anymore. So in this light, what Randy is saying is true.
>
> In fact, I do not know of ANY IXP on the planet that is a "Router" (i.e.
the
> original CIX design). Those that are "routers" are not IXPs - they are
> transit services with "IX" added as a marketing ploy.
>
> Any ISPs who wants to gain the benefit of an IXP _must_ be willing to
> co-locate their own router on the IXP. There are a variety of reasons
> (business, technical, security, policy, etc). If you need all the reasons
> written down, let me know and I'll document them.
>
> Putting a router on the IXP so other ISPs can get a lease line into it
(i.e.
> a L3 on top of a L2) is something I do not recommend. It changes the IXP
> into a pseudo transit service. The IXPs that have gone down this path
> eventually turn into transit services (Taiwan's IXPs come to mind). Yes,
it
> appears to be "helpful" to those ISPs who cannot afford a router, but the
> track record for keeping the IXP an IXP (and not a transit service) is
> bleak.
>
> Also - excuses on "the router is too expensive" are eliminate when you
build
> an ethernet based IXP with a Route Server (RS) or Route Reflector (RR).
This
> is how you get routers as small as Cisco 1600Ms on an IXP - they peer with
> the RS or RR.
>
> BTW - there are three modes of ethernet based IXPs:
>
> + Meshed Peering
> + Route Reflector Based Peering
> + Router Server Based Peering
>
> Meshed and RS are the most common on the IXPs in the world. RR based IXPs
> are places where the IXP is working to keep their initial capital cost
low.
>
> My recommendation for an IXP like in Uganda would to allow Meshed + RS or
> Meshed + RR.
>
> -> Route Servers require a Unix box. They will allow the small ISPs with
> little router (i.e. like the Cisco 1600M) to peer at the IXP along side
big
> ISPs who just peer with the Meshed peering technique. The expense excuse
for
> RSs are gone - Abha Ahuja is going to help expand the section in my IXP
> whitepaper to show how a RS impimented at a small IXP.
>
> -> Route Reflectors require also require a Unix Box with Gated or a router
> supporting BGP RR. They also allow the little guys to peer with the big
> guys. The big disadvantage of a RR is that is requires a AS number for the
> IXP and adds an AS number to the BGP path. We - Cisco - may put in a knob
to
> change the extra hop issues. We've not decided if it is worth the risk of
> customers screwing up their networks by turning it on where it should not
be
> turned on. The new documentation on a low cost Route Server example might
> eliminate the need for RR based IXPs. So we're going down that path before
> tweaking the BGP code.
>
> In summary - keep away from ISPs connecting lease lines into an "IXP
Router"
> on the IXP. It has never proved to scale or survive as a "IXP." Ethernet
> Switch based IXPs are the way to go. Meshed with a Route Server or a Route
> Reflector allows the small players with small routers to interconnect with
> the big players.
>
> If you can afford the Unix box - I would go with a L2 IXP with a Route
> Server. The new documentation that Abha and I are going to help write will
> give you a step by step template on how to make it happen.
>
> Barry
>
> PS - Abha will be at AFNOG - so people going can pick her brains.
>
>
>
>
>
> > -----Original Message-----
> > From: owner-techies@alpha.eahd.or.ug
> > [mailto:owner-techies@alpha.eahd.or.ug]On Behalf Of Randy Bush
> > Sent: Thursday, May 03, 2001 3:10 PM
> > To: Lunghabo James
> > Cc: techies@uixp.co.ug
> > Subject: Re: Comments ......
> >
> >
> > >> It seems to me like the simple setup is actually the better one in
this
> > >> case from arguments put forward.
> > > Why ?
> >
> > was covered in previous mail, but
> >   o it is simpler
> >   o it is less costly
> >   o it is more reliable
> >   o it takes less maintenance by the ix staff
> >   o it technically works better as it does not add cruft to the bgp
> >     and bgp paths
> >   o it allows bi-lateral peering as well as multi-lateral
> >
> > and for all the above and more, all the exchange points in
> > europe, asia, the
> > states, ... use it.  only a few folk in isolated areas have been
suckered
> > into the layer 3 tech-nocolianist dependence on a router vendor.
> >
> > randy
> >
>
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