Mailing List Archive

Re: Worldly Thoughts - Regionalizing Peering
Toodles,

] > 2. Even better, accept my routes into your network but only use them
] > within region... I know this isn't nearly as easy as #1, so I don't
] > expect it to happen, but it would be a significant performance benefit
] > for the local traffic your customers in the region are generating which
] > is headed towards me. Once outside the region, of course, you ignore the
] > direct routes from me and just give them to my transit provider.
]
] It becomes very entertaining to scale the above model (although it does
] provide an excuse to use nearly every BGP routing feature in IOS. :-)

The model scales well, imho. Regionalize your network into
pieces. Apply each of the pieces into 1 or more proximities to a
NAP|MAE.

Apply set filter lists onto peering sessions for appropriate
peers.

Let me expound.

I run Internet-Net.net. I have a POP in every city w/ over 10,000
people.

I aggregate M number of POPs to N number of Hubs.

(use acronym NXP to mean network exchange point.....)

I am connected to P number of NXPs.

I go through each of my N Hubs, and identify if he is
or is not in Pn's region. If he is, I add NXPn's peers to the
allow list. If he's not, I don't.

Won't this work? Is it "too confusing"?

Let's say I have 1 HUB in Arizona. I decide that they are in the
region of MAE-W, PACBELL, and the NXP in Phoenix. So, I accept
routes from everyone at any of those NXPs, and I give my routes
for this HUB only, to everyone at the NXP. I don't tell them
about my route to customers homed to San Mateo, because I don't
want to carry their traffic there, only stuff that's topolgically
'close' to them, as I feel that benefit to my customers is worth
the peering relationship.

I have a HUB in San Mateo. I decide that he's in the region of
MAE-W and PACBELL and MAE-LA, but not the NXP in Phoenix. So, I
accept routes from the folks at those NXPs, and only give the
routes for my folks homed to my San Mateo HUB. My San Mateo
Customers get to the folks at the NXP, and the other providers
customers get to my customers CLOSE to the NXP in San Mateo.
However, I don't have to backhaul them to another larger
aggragation point, or to another NXP at which I hand off packets
to their transit provider.

Benefit: I gain low latency transit to most everyone.

Drawback: It is technically challenging to create an automate
system to regionalize and create appropriate filter lists.

----

Perhaps this is a problem that's only challenging to the smaller
folks, those of us w/out the nationwide DS3|OC3 networks.
However, I do feel it's a worthy problem, and one that would
benefit the NANOG community were it intelligently solved.

-a
- - - - - - - - - - - - - - - - -
Re: Worldly Thoughts - Regionalizing Peering [ In reply to ]
On Sat, 11 May 1996, Alan Hannan wrote:

> I run Internet-Net.net. I have a POP in every city w/ over 10,000
> people.

> Benefit: I gain low latency transit to most everyone.
>
> Drawback: It is technically challenging to create an automate
> system to regionalize and create appropriate filter lists.

> Perhaps this is a problem that's only challenging to the smaller
> folks, those of us w/out the nationwide DS3|OC3 networks.
> However, I do feel it's a worthy problem, and one that would
> benefit the NANOG community were it intelligently solved.

Here's another scenario. I run Web o' Wonder, the most popular web site on
the net but magazine writers are complaining it is slow and unreliable. I
hire a net guru who tells me the problem is I am too big for one site.
She says I should install WWW servers at several geographically diverse
locations, preferably at or near NXP's. She explains that the servers
at my main site (all CNAMEs for www.web-o-wonder.com) will no longer serve
documents but will determine the topological closest site to the client
based on route server info and issue redirects to seamlessly and speedily
serve the client documents from the site closest to them in the topology.

Seems to me that this scenario would also benefit from a tool and database
that could determine topological "closeness" even if it doesn't need to
generate filter lists.

If this scenario were easier to implement it could reduce the load of the
major exchange points by encouraging traffic to stay closer to the network
periphery.

Michael Dillon Voice: +1-604-546-8022
Memra Software Inc. Fax: +1-604-546-3049
http://www.memra.com E-mail: michael@memra.com

- - - - - - - - - - - - - - - - -
Re: Worldly Thoughts - Regionalizing Peering [ In reply to ]
At 8:24 PM 5/11/96, Alan Hannan wrote:

> The model scales well, imho. Regionalize your network into
> pieces. Apply each of the pieces into 1 or more proximities to a
> NAP|MAE.

Been there, done that.... I've already stated my view on the
scalability of such arrangements.

> Benefit: I gain low latency transit to most everyone.
>
> Drawback: It is technically challenging to create an automate
> system to regionalize and create appropriate filter lists.

It also complicates every peering relationship and multi-homed
customer connection, as you have to worry about both multiple
external AS's and your internal routing redistribution from all
of these regional routing clouds.

If you presume a fairly dense set of interconnects among transit
providers, then you're not going to get a significant improvement
in latency despite the added complexity.

/John



- - - - - - - - - - - - - - - - -
Re: Worldly Thoughts - Regionalizing Peering [ In reply to ]
>
> The model scales well, imho. Regionalize your network into
> pieces. Apply each of the pieces into 1 or more proximities to a
> NAP|MAE.
>
> Apply set filter lists onto peering sessions for appropriate
> peers.
>
> Let me expound.
>
> I run Internet-Net.net. I have a POP in every city w/ over 10,000
> people.
>
> I aggregate M number of POPs to N number of Hubs.
>
> (use acronym NXP to mean network exchange point.....)
>
> I am connected to P number of NXPs.
>
> I go through each of my N Hubs, and identify if he is
> or is not in Pn's region. If he is, I add NXPn's peers to the
> allow list. If he's not, I don't.
>
> Won't this work? Is it "too confusing"?
>
> Let's say I have 1 HUB in Arizona. I decide that they are in the
> region of MAE-W, PACBELL, and the NXP in Phoenix. So, I accept
> routes from everyone at any of those NXPs, and I give my routes
> for this HUB only, to everyone at the NXP. I don't tell them
> about my route to customers homed to San Mateo, because I don't
> want to carry their traffic there, only stuff that's topolgically
> 'close' to them, as I feel that benefit to my customers is worth
> the peering relationship.

Unless you were precient when you allocated your CIDR blocks, this means
that you will not be able to aggregate your networks.

Erik


> I have a HUB in San Mateo. I decide that he's in the region of
> MAE-W and PACBELL and MAE-LA, but not the NXP in Phoenix. So, I
> accept routes from the folks at those NXPs, and only give the
> routes for my folks homed to my San Mateo HUB. My San Mateo
> Customers get to the folks at the NXP, and the other providers
> customers get to my customers CLOSE to the NXP in San Mateo.
> However, I don't have to backhaul them to another larger
> aggragation point, or to another NXP at which I hand off packets
> to their transit provider.
>
> Benefit: I gain low latency transit to most everyone.
>
> Drawback: It is technically challenging to create an automate
> system to regionalize and create appropriate filter lists.
>
> ----
>
> Perhaps this is a problem that's only challenging to the smaller
> folks, those of us w/out the nationwide DS3|OC3 networks.
> However, I do feel it's a worthy problem, and one that would
> benefit the NANOG community were it intelligently solved.
>
> -a
- - - - - - - - - - - - - - - - -
Re: Worldly Thoughts - Regionalizing Peering [ In reply to ]
At 07:24 PM 5/11/96 -0500, Alan Hannan wrote:
>
> Toodles,
>
>] > 2. Even better, accept my routes into your network but only use them
>] > within region... I know this isn't nearly as easy as #1, so I don't
>] > expect it to happen, but it would be a significant performance benefit
>] > for the local traffic your customers in the region are generating which
>] > is headed towards me. Once outside the region, of course, you
ignore the
>] > direct routes from me and just give them to my transit provider.

> Benefit: I gain low latency transit to most everyone.
>
> Drawback: It is technically challenging to create an automate
> system to regionalize and create appropriate filter lists.

Another drawback to this model is that if you peer with people at one
exchange and one exchange only you would only give them routes that are
within the local region, and not all of your routes. This may be a problem.
It may not. (Plus you could always just setup a system that marks where you
peer with people at and have it allocate routes accordingly, i.e. if you
only peer at one place you blow them everything there.)


Justin Newton * You have to change just to stay
Internet Architect * caught up.
Erol's Internet Services *

- - - - - - - - - - - - - - - - -
Re: Worldly Thoughts - Regionalizing Peering [ In reply to ]
>> Let's say I have 1 HUB in Arizona. I decide that they are in the
>> region of MAE-W, PACBELL, and the NXP in Phoenix. So, I accept
>> routes from everyone at any of those NXPs, and I give my routes
>> for this HUB only, to everyone at the NXP. I don't tell them
>> about my route to customers homed to San Mateo, because I don't
>> want to carry their traffic there, only stuff that's topolgically
>> 'close' to them, as I feel that benefit to my customers is worth
>> the peering relationship.

>Unless you were precient when you allocated your CIDR blocks, this means
>that you will not be able to aggregate your networks.

Well, that is the problem with CIDR, if you aggregate, you lose control
of details. However, it is possible to apply the regional peering model
with relative ease by using tags/communities to tag the origin of your
routes as well as routes you hear from your peers and filter
accordingly. As for aggregates you can do one of two things:


1) let your specifics float around on your backbone as well as the
aggregates, and pass on the specifics to regional peers, or the
aggregates to "complete" peers (to everyone else pass nothing or
announce them only your aggregates); or

2) be more selective with respect to long specifics and either announce
none of those to your regional peers or announce the aggregates (even
though they include non-regional information).

You also have to sortof trust your regional peers to give you only
reasonably regional routes; if they lie, well, they only get half the
route back from your non-regional sites to theirs, the rest they must
get through somewhere else.

>Erik


Nick
- - - - - - - - - - - - - - - - -
Re: Worldly Thoughts - Regionalizing Peering [ In reply to ]
On Sun, 12 May 1996, John Curran wrote:

|} At 8:24 PM 5/11/96, Alan Hannan wrote:
|}
|} > Benefit: I gain low latency transit to most everyone.
|} >
|} > Drawback: It is technically challenging to create an automate
|} > system to regionalize and create appropriate filter lists.
|}
|} It also complicates every peering relationship and multi-homed
|} customer connection, as you have to worry about both multiple
|} external AS's and your internal routing redistribution from all
|} of these regional routing clouds.

The level of complication is dependant on how the network is structured.
For example, in a topology which reflects internal routes between
access/service and core nodes, it will be treated as a single AS, or as an
alternate it can be treated as external. This is because you've
distributed the processing throughout the majority nodes in the network,
rather than a design which is doing the processing on the edges of the
network.

This greatly eases the amount of constant re-configuration and work that
is required to connect to a dense set of exchange points.


-jh-

- - - - - - - - - - - - - - - - -
Re: Worldly Thoughts - Regionalizing Peering [ In reply to ]
Justin W. Newton writes:
>
>Another drawback to this model is that if you peer with people at one
>exchange and one exchange only you would only give them routes that are
>within the local region, and not all of your routes. This may be a problem.
>It may not.

It would be. What happens if one of your connections to a peering
point goes down? You can't fall back to go through another peering
point because they are not sending you the routes there. The way to
do it is probably with either AS padding or BGP communities. I've
never played with them, but Enke Chen from MCI wrote a draft on the
subject which he spoke about at the last NANOG.

Alec

--
+------------------------------------+--------------------------------------+
|Alec Peterson - chuckie@panix.com | Panix Public Access Internet and UNIX|
|Network Administrator | New York City, NY |
+------------------------------------+--------------------------------------+
- - - - - - - - - - - - - - - - -
Re: Worldly Thoughts - Regionalizing Peering [ In reply to ]
> Drawback: It is technically challenging to create an automate
> system to regionalize and create appropriate filter lists.

I always did enjoy a challenge.

It's really pretty trivial up on the whiteboard. My model includes BGP
confederations to define regions. In the absence of enough IP Addresses to
divide your allocations by confederate AS, I am fairly sure the use of
communities could be used to hack the distribution of more specifics into
conforming the way you want.

This is all from memory. I haven't revisted this model much since I
developed my first one late last year. Maybe they're some new knobs which
make it even easier.

Dave

--
Dave Siegel Sr. Network Engineer, RTD Systems & Networking
(520)623-9663 x130 Network Consultant -- Regional/National NSPs
dsiegel@rtd.com User Tracking & Acctg -- "Written by an ISP,
http://www.rtd.com/~dsiegel/ for an ISP."
- - - - - - - - - - - - - - - - -
Re: Worldly Thoughts - Regionalizing Peering [ In reply to ]
Dave Siegel writes:
>
>Since these are designed to be regional exchanges, one would presume that
>transit is still available elsewhere.
>
>Even at the large carrier level, I should think that the priority NAPs,
>as well as the private interconnects, would contain complete information
>on the other networks to back up any failure to route at a regional exchange.

Er, um, well yes, but ideally if you get peering from all the big
boys, you wouldn't need to purchase transit from someone.

I think the idea of only exchanging local routes at any given regional
exchange is not a bad idea, but I don't see how it would really end up
working properly in a fluctuating environment.

Alec

--
+------------------------------------+--------------------------------------+
|Alec Peterson - chuckie@panix.com | Panix Public Access Internet and UNIX|
|Network Administrator | New York City, NY |
+------------------------------------+--------------------------------------+
- - - - - - - - - - - - - - - - -
Re: Worldly Thoughts - Regionalizing Peering [ In reply to ]
> >Since these are designed to be regional exchanges, one would presume that
> >transit is still available elsewhere.
> >
> >Even at the large carrier level, I should think that the priority NAPs,
> >as well as the private interconnects, would contain complete information
> >on the other networks to back up any failure to route at a regional exchange.
>
> Er, um, well yes, but ideally if you get peering from all the big
> boys, you wouldn't need to purchase transit from someone.

Did I mention purchase anywhere? I don't think I did. It's not what I'm
talking about. What I'm talking about is a set of places in the country
where you have access to everything in your peers peoples network.

> I think the idea of only exchanging local routes at any given regional
> exchange is not a bad idea, but I don't see how it would really end up
> working properly in a fluctuating environment.

I see absolutely nothing wrong with it as long as normal engineering
considerations are taken into account.

These would include redundancy/fallover, among many other things.

Dave

--
Dave Siegel Sr. Network Engineer, RTD Systems & Networking
(520)623-9663 x130 Network Consultant -- Regional/National NSPs
dsiegel@rtd.com User Tracking & Acctg -- "Written by an ISP,
http://www.rtd.com/~dsiegel/ for an ISP."
- - - - - - - - - - - - - - - - -