[j-nsp] Policy Statement Question

[Scott Morris]

While I'm much more familiar with the order of preferences in the Cisco
world than in the Juniper one, I still believe there are many options looked
at BEFORE AS-Path length is.

You may try manipulating the Local Preference on the routes that you want to
go a different direction, and you should find this all suits your purposes
much easier.  

While I'm not sure where you are in the hierarchy of things, if you are
passing BGP information on to other providers, your changing the AS-Path
with prepending will influence decisions further down the pipeline which may
not be in your best interest.  However, LocalPref will make your local
decisions the way you want.

HTH,

Scott
 

-----Original Message-----
From: juniper-nsp-bounces at puck.nether.net
[mailto:juniper-nsp-bounces at puck.nether.net] On Behalf Of Chris Davies
Sent: Saturday, January 28, 2006 1:25 PM
To: juniper-nsp at puck.nether.net
Subject: [j-nsp] Policy Statement Question

I have two current issues which might have one solution.  Our initial
testing shows that the Juniper reduced average latency about 10ms, so, even
though our Cisco wasn't showing any real signs of cpu usage, it appears (and
feels like) the Juniper has made an improvement in performance which was a
small surprise.

The issue I'm working with now is that we buy transit from two providers, a
Tier 1 (Cogent) and a Tier 2 (Internap) if you wanted to use 'old' terms.
The problem I am running into is that since Internap is technically a Tier 2
(they buy transit from Tier 1 providers), only 25k of the 175k routes have
shorter ASPaths to the destination.

Since Internap is only adding 1 router hop and 1 AS Hop, I should ASPad on
Cogent's side.  That would perhaps level the playing field for inbound
traffic.

If I understand this right, can someone do a sanity check?  (The IOS2junos
convertor really made things a mess for me, so, I tried to figure out what
it needed and stripped out the rest of it)

policy-statement aspad_Cogent {
     term aspad_Cogent {
         then as-path-prepend 11110;
     }
}

Do I need a from condition if I want to unconditionally aspad?

If I understand it, I do not want an accept here since I want the next
policy statement to also be executed.

Now, on my A-Peer with Cogent (they use multihop), I would set

export [ aspad_Cogent bgp_distributes ]

At that point, I need to

clear bgp neighbor (a-peer's ip) soft

to send the config.

AS Padding on my exports should result in inbound traffic perhaps choosing a
better path since the ASPath's across Cogent and Internap would be a little
more balanced.  When I add another provider alongside these two, if it is
another Tier 1 provider, I would probably need to pad their incoming as
well.

If someone could give this a quick sanity check, I'd appreciate it.  12
years of IOS -> Junos has been a bit of a challenge.  :)

Thanks.
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