Subject: Re: what is a site?

From: Tomohide Nagashima <[email-masked]>
Date: Mon, 26 Mar 2001 19:57:31 +0900

Hello,

>we also don't need any specific definition of
>what is a site - all that can possibly do is to constrain thinking into
>the future.

As I also think we should not constrain concept of site. But I belive we 
still need some minimun defenition of site, or need some example that show 
such a set is site or not.

For example, how about it?

There is a company that has two sets of network in two place.
As each network is too far, this company get connectibity from 
two ISPs( ISP1 has prefixes in TLA1, ISP2 has prefixes in TLA2). 
And this company want to communicate this two network without 
Grobal network, this company connect this two network with 
released line. like this;

 [TLA1]      [TLA2]
   |            |
<NLA1-1>-----<NLA2-1>

( NLA1-1 is from TLA1, and NLA2-1 is from TLA2 )

then can we call a set of NLA1-1 and NLA2-1 is a site ?

I belive that this set is not a site but two sites.
but if we define site is whatever I want it to be,
then someone will regard this a set of two networks is a site.

----
Tomohide Nagashima
[email-masked]
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From: Kevin Wang <[email-masked]>
Date: Mon, 26 Mar 2001 09:00:44 -0800

Hi,

We can consider that in your example there are two Autonomous Systems, and
each is a site. Do you mean this?

Kevin

---

From: Kevin Wang <[email-masked]>
Date: Mon, 26 Mar 2001 09:02:36 -0800

Hi,

Kevin

---

From: Greg Maxwell <[email-masked]>
Date: Mon, 26 Mar 2001 10:15:15 -0500 (EST)

> each is a site. Do you mean this?

I think the best description of a site for these purposes is:

"A site and an autotomous system would be the same, however, we are
conserned with ASN proliferation and therefor only assign ASNs to ASes
which actually require enumeration for the purposes of operating global
routing protocols".

So a site is a ASN potentially without BGP.

This seems to fit togeather the idea of site-locals and the concept of
having a unified routing policy within ASes.

---

From: Robert Elz <[email-masked]>
Date: Tue, 27 Mar 2001 01:38:50 +1000

Date:        Mon, 26 Mar 2001 19:57:31 +0900
    From:        Tomohide Nagashima <[email-masked]>
    Message-ID:  <[email-masked]>

  | As I also think we should not constrain concept of site. But I belive we 
  | still need some minimun defenition of site, or need some example that show 
  | such a set is site or not.

Yes, a minimum definition is needed - that is, a site must be internally
connected.   That's all I would say about it.   As presently defined sites
cannot overlap, but it isn't at all beyond the realms of possibility that
we might want to change that sometime in the future, so I wouldn't even
include that in the definition.

  | I belive that this set is not a site but two sites.
  | but if we define site is whatever I want it to be,
  | then someone will regard this a set of two networks is a site.

It can be one site, two sites, or N sites, for any value of N >= 0.

Take your diagram, and stick the two nets with the two different NLAs
in one building (in one room perhaps), rather than a long way apart.
Logically the situation is exactly the same, but almost everyone would
consider that to be one site.

On the other hand, the admins of the company may split it into seperate
sites - one for the research dept, one for sales, one for admin, ...

Basically, it should be whatever makes sense for the administrators.

kre

---

From: Tomohide Nagashima <[email-masked]>
Date: Tue, 27 Mar 2001 01:18:05 +0900

Hi,

I thought that these AS is for "the company" (which is originally defined
by my previous e-mail), right?  Then, sorry but I wonder if "a site" and 
"Autonomous System" is not same. 

><NLA1-1>-----<NLA2-1>

Both NLA1-1 and NLA2-1 is allocated to "the company". and I belive
that NLA1-1 and NLA2-1 are different sites. i.e. "the company" has
two sites.

And I select definition of the term AS from rfc 1771;
> The use of the term Autonomous System
>   here stresses the fact that, even when multiple IGPs and metrics are
>   used, the administration of an AS appears to other ASs to have a
>   single coherent interior routing plan and presents a consistent
>   picture of what destinations are reachable through it.

I thought that "the company" operate this two NLA network with same routing
plan, we can consider that a set of NLA1-1 and NLA2-1 is same AS, but
the line between TLA1 and NLA1-1 will not present any reachability to anyone
in IPv6 Grobal Network, so I also belive this set (of NLA1-1 and NLA2-1) is not
one AS.

Greg idea that this set has two AS is right in some part. But if 
NLA1-1(=site=AS) and NLA2-1(=site=AS) was operated with same IGP,
Are these two AS is different AS ??

I belive a site is a site. That is not more or less.
The concept of AS or NLA holder has no relationship with concept of site,
What do you think about it ?

----
Tomohide Nagashima

From: Greg Maxwell  <[email-masked]>

---

From: "Joris Dobbelsteen" <[email-masked]>
Date: Tue, 27 Mar 2001 16:41:51 +0200

>-----Original Message-----
From: [email-masked]
>[mailto:[email-masked]]On Behalf Of Tomohide Nagashima
>Sent: Monday, 26 March 2001 12:58
>To: [email-masked]
>Cc: [email-masked]; [email-masked];
>[email-masked]
>Subject: Re: what is a site?
>
>
>Hello,
>
From my opinion this can be a single site or two sites, it's just an
administrative term in network management.

My definition of a site is a computer network, that can exist of one or more
links that all have there own services and would be able to preform it's
basic functions without the need of an additional site. Probably here it's
get complicated and this is were others may disagree.

For me, sites exist for reasons of security (e.g. high-security envorment
connected to an other network), network load balancing (e.g. distributing
servers or slow links) or any other reason. Most sites are on a specific
geographic posisition, but this usually has todo with the slow links between
the sites.
Note here that I'm not saying that two (or more) links that are separated by
a big space

I rather use the term link instead of network to identify a line where one
or more computers are connected to AND where they all have direct access to
each other without the need to go through a router or proxy.
Note that I don't treath hubs and switches as such routers, but just a part
of the link.

 [TLA1]                   [TLA2]
   |                        |
<NLA1-1>----slow-line----<NLA2-1>

As a illustion with the same meaning as above, I would threat this as one
site if all systems for authentication, DNS, DHCP (examples) and other
direct requirements for the network are all located on [TLA1]. Instead if
they have both the services then they COULD be two sites (it would seem
sense, but it's not nescesary to me).
Note that the services may be the same, the authentication server on [TLA1]
may be relicated with [TLA2]...

>[email-masked]

- Joris
  [email-masked]