Subject: [Pce] About PCE inte-AS conectivity

From: Manuel Dominguez Dorado <[email-masked]>
Date: Wed, 11 Jun 2008 15:23:37 +0000

Hello,

I'm interested on PCE issues, specially those issues related to inter-AS 
PCE. In order to provide accurate results, I am trying to use the most 
real network model (at least, as real as possible). So, this is my question:

When in PCE WG it is said: "The PCE WG will work on application of this 
model within a single domain or within a small group of domains (where a 
domain is a layer, IGP area or Autonomous System with limited visibility 
from the head-end LSR). At this time, applying this model to large 
groups of domains such as the Internet is not thought to be possible, 
and the PCE WG will not spend energy on that topic".

What is the size we are speaking about? For example, a set of 200 
PCE-based autonomous systems and each one of them having 50 direct 
adjacencies could be a good example? What would be the highest limit 
(for both, number of implied AS and adjacency degree)? I need this 
information in order to design solutions that are scalable enough to be 
operative.

Excuse me if it is an off-topic question. I have looked for the answer 
for months but I found nothing related to Interdomain PCE.

Thanks in advance.

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From: "Adrian Farrel" <[email-masked]>
Date: Thu, 12 Jun 2008 01:56:47 +0100

Hello Manuel,

> PCE.

Welcome aboard.

> In order to provide accurate results, I am trying to use the most

Very good question. And hard to answer precisely.
The intention of the text in the working group charter is to limit the scope 
of the PCE work to "connection-oriented" internet technologies (not IP 
forwarding), and to solve the problem of selecting path through a known set 
of domains rather than selecting the domain level path.
It was considered sensible, when the working group was formed to be cautious 
about our scope, and to establish the technology as functional within a 
reasonably controlled environment.

Section 5.1.15 of RFC 4657 gives some guidelines.
   - number of PCCs (1000/domain)
   - number of PCEs (100/domain)
   - number of PCCs communicating with a single PCE (1000)
   - number of PCEs communicated to by a single PCC (100)
   - number of domains (20)
   - number of path request messages (average of 10/second/PCE)
   - handling bursts of requests (burst of 100/second/PCE within a 10-
     second interval).

But you will note that this does not talk about the connectedness of the 
domains. Neither the number of peer domains, nor the number of connections 
to any peer domain is mentioned. I would expect that these numbers would be 
unchanged from normal operation of (say) ASes in the Internet.

I would say that some of the numbers listed above show top-end figures and 
one would not necessarily expect, for example, a standard deployment to have 
one PCC communication to 100 PCEs.

> for months but I found nothing related to Interdomain PCE.

Hope that helps.
Adrian

---

From: Manuel Dominguez Dorado <[email-masked]>
Date: Thu, 12 Jun 2008 09:08:48 +0000

Hello,

> Welcome aboard.

Thanks. :-).

>   - number of PCEs communicated to by a single PCC (100)

Then, should I understand that, in terms of inter-AS PCE, a domain is a 
an AS? It is very good for me. I have been supposing an interdomain 
environment composed by 200-300 ASes, for some months. having only 20 
domains is great for me, he, he.

> domains. Neither the number of peer domains, nor the number of 
> connections to any peer domain is mentioned. I would expect that these 
> numbers would be unchanged from normal operation of (say) ASes in the 
> Internet.

OK.

> 
> I would say that some of the numbers listed above show top-end figures 
> and one would not necessarily expect, for example, a standard deployment 
> to have one PCC communication to 100 PCEs.
> Hope that helps.

OK. Thank you very much, you have not given me answers for all my 
questions but, any way, you have helped me a lot.

> Adrian

Thank you again, Adrian.

Best regards.

---

From: "Adrian Farrel" <[email-masked]>
Date: Thu, 12 Jun 2008 14:37:58 +0100

Once last thing, Manuel.

> domains is great for me, he, he.

Yup.
>From RFC 4657
   Domain: Any collection of network elements within a common sphere of
   address management or path computational responsibility.  Examples of
   domains include Interior Gateway Protocol (IGP) areas, Autonomous
   Systems (ASs), multiple ASs within a service provider network, or
   multiple ASs across multiple service provider networks.

Adrian