nanog mailing list archives

Re: Policy Routing


From: "Alexei Roudnev" <alex () relcom EU net>
Date: Sun, 26 Aug 2001 09:44:16 -0700


I don't see any policy routing in this example. ou don't need polic routing if you
want to direct ALL traffic
by one provider or if you want to have preferences affected ALL traffic.

You need polit routing if, for example, you have two providers, ISP-A and ISP-B,
and two customers, C-A and C-B, and
(by any reasons) want C-A to work b NSP-A and C-B to work by NSP-B (for IN and OUT
traffic).

Else, it's quite enougph to configure localpreferences and metrics.

----- Original Message -----
From: "John Fraizer" <nanog () Overkill EnterZone Net>
To: "Jeff Cates" <catesjl9394 () yahoo com>
Cc: <nanog () merit edu>
Sent: Saturday, August 25, 2001 9:56 PM
Subject: Re: Policy Routing




Replying to my own post with a bit more. (Forgive me!)

Rereading your post, one would believe that since "Company X" is a BGP
customer of yours, you're going to be sending them a full view.  Unless
there is a knob that I'm not familiar with, that means that you're going
to be sending them the _BEST_ routes that you see in your core and not
just those from "NSP A" to which you are proposing to policy-route all of
"Customer X's" traffic.  If this is indeed the case, I would think that
policy-routing the customers traffic destined for "prefix Y" via a
path other than the path listed in the NLRI you're sending "Customer X" on
their BGP feed is outright fraud.

Again, this is in the absence of full disclosure and it is my (non
esquire) opinion.


---
John Fraizer
EnterZone, Inc


On Sun, 26 Aug 2001, John Fraizer wrote:



I would be very upset if I were "Company X" and I found out that you were
policy-routing my traffic to the "cheap" connection vs the best
connection.

Is it just me or do others on the list believe that in the absence of full
disclosure this would be shady at best?


---
John Fraizer
EnterZone, Inc


On Sat, 25 Aug 2001, Jeff Cates wrote:


Hello,

I am a network engineer at a regional southeast USA
NSP. I am looking for some recommendations concerning
a scenario that has been presented to me.

My company is attempting to obtain company X's
Internet transit traffic, which will be  BGP-4 peering
over either a T-3 or OC-3. Due to financial reasons,
my upper management has proposed that I route company
X's Internet traffic via a specific NSP that we peer
with, we'll call them NSP-A. Apparently, NSP-A has a
substantially cheaper rate than our other upstrem
providers and it is anticipated that this customer
will be sending a full T3 or OC-3's worth of traffic
to us.

Redirecting inbound traffic to company X via NSP-A can
be accomplished very easily through use of AS path
prepending, however, coming up with a solution for
egress traffic from company X to NSP-A, via our AS,
has proven a bit more challenging :-).

The only feasible solution that I've been able to come
up with is to stick customer X directly on the router
that peers with NSP-A and employ the use of policy
routing, which would enable me to set the next hop for
company X's traffic to the peering address on NSP-A.

Our NSP-A peering router is a Cisco 12016, running IOS
12.0(16)S2 and it has 256MB of DRAM.

Additionally, it is configured with NetFlow and dCEF
switching.

I've never employed policy routing in this type of
environment and I am concerned about the overhead that
it might place on the router or on the traffic
traversing the interface.

I've also thought about MPLS TE, however, our core
backbone does not run MPLS and even if we did, I
believe I would still have to policy route the traffic
to NSP-A once the MPLS label was popped off the last
router in the path in transit to the NSP-A peering
router.

Any ideas or comments would be greatly appreciated.

Thanks in advance,

Jeff

catesjl9394 () yahoo com


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