Fwd: Virtual Cisco North American hub? - HECnet

24 Feb 2013

Peter,

If I peered with your three locations, and set the cost of each link to =
be proportional to the distance (or at least speed/latency), then my =
network would prefer the link with the lowest cost, but still have the =
other links as redundant in the case of a link failure.

You knew nothing about the internal topology of my as, ad you are
assuming my BW is better than your BW.

The routing problems are similar to those with BGP.   If I'm routing to =
your AS number, I'm going to want to hand it over to the geographically =
closest point, and assume your network is better at connecting all of =
it's internal parts.   BGP AS's don't expose the internal structure of =
the network either.

BGP is a distance-vector protocol, DECnet/ISIS is link state,
completely different set of tools.

If my AS is peering with your AS, I can send you "deaggregated routes
with comunity "do not export" and attach my IGP metrics (and policy)
and send that to you with MED. 

In BGP between ASes for econimical reasons you do closest exit to the
peer, so traffic is assumetric, you can listen to MED but if both
sides does it we might be back to assymetric routes. 

So in "real world" buisiness polcy is implemented with BGP.

With DECnet routing or ISIS L1/L2 you have much less of a tols, and
you can not filter prefixes.

The only thing I was trying to do was to suggest, if we want to make a
backboone of hubs, they better be in the same area. 

I saw a bunch of messages in this theread that I think are related to
MTU, the router-tunnel interface has to match the path MTU or things
like routing vectors for high node-numbers will be truncated..

-p

Ian

On 2013-02-23, at 9:05 PM, Peter Lothberg <roll at Stupi.SE> wrote:

Would you care to elaborate? My knowledge of DECnet routing is very =
limited.=3D
=20
It;s no different than I-ISIS.
=20
Within a area you treat all the boarder gateways (are routers) the
same, so for itgoing packets a node inside the area will pick it's
closest area router with external connectivity to senda outgoing
packet through.=20
=20
Another area will pick ANY router it think is usefulle for the
destination area, regardless of the internal topology of that area..=20=

=20
Bottom line:
=20
I have area 59 in Stockholm, Uppsala, Reston VA, and Sunnnyvave CA, if
we want to have a usefull "global core" it needs to be in the same
area....=20
=20
-P
=20
=20
=20
=20
-brian
=20
On Feb 23, 2013, at 19:30, Peter Lothberg <roll at Stupi.SE> wrote:
=20
On 02/23/2013 07:21 PM, Cory Smelosky wrote:
I've managed to coax my provider in to giving me another IP
(apparently 5 IPs come with my plan=3D05), so I can get a virtual =
cisco
up on my VPS (in Canada).
=3D20
Brian, would you like to get this all joined in to the mesh?   Is a =
NA
hub still needed or has someone else offered one? (This'd be on an
unmetered gigE pipe)
=3D20
I think running a hub on an emulated router maybe isn't the best =
idea.
(sorry to say so)
=3D20
We also have to take in to account how to get some kind of =
resonalble
routing, as the inside of an area is not exchanged with other areas.
=3D20
-P
=20
=20
=20
=20
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<html><head><meta http-equiv=3D"Content-Type"
content=3D"text/html =
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-webkit-nbsp-mode: space; -webkit-line-break: after-white-space; =
">Peter,<div><br></div><div>If I peered with your three
locations, and =
set the cost of each link to be proportional to the distance (or at =
least speed/latency), then my network would prefer the link with the =
lowest cost, but still have the other links as redundant in the case of =
a link failure.</div><div><br></div><div>The routing
problems are =
similar to those with BGP. &nbsp;If I'm routing to your AS number, I'm =
going to want to hand it over to the geographically closest point, and =
assume your network is better at connecting all of it's internal parts. =
&nbsp;BGP AS's don't expose the internal structure of the network =
either.</div><div><br></div><div>Ian</div><div><br><div><div>On
=
2013-02-23, at 9:05 PM, Peter Lothberg &lt;<a =
href=3D"mailto:roll at Stupi.SE">roll at Stupi.SE</a>&gt;
wrote:</div><br =
class=3D"Apple-interchange-newline"><blockquote
type=3D"cite"><blockquote =
type=3D"cite">Would you care to elaborate? My knowledge of DECnet =
routing is very limited.=3D<br></blockquote><br>It;s no different than
=
I-ISIS.<br><br>Within a area you treat all the boarder gateways (are =
routers) the<br>same, so for itgoing packets a node inside the area will =
pick it's<br>closest area router with external connectivity to senda =
outgoing<br>packet through. <br><br>Another area will pick ANY router it
=
think is usefulle for the<br>destination area, regardless of the =
internal topology of that area.. <br><br>Bottom line:<br><br>I
have area =
59 in Stockholm, Uppsala, Reston VA, and Sunnnyvave CA, if<br>we want to =
have a usefull "global core" it needs to be in the same<br>area.... =
<br><br>-P<br><br><br><blockquote
type=3D"cite"><br><br>-brian<br><br>On =
Feb 23, 2013, at 19:30, Peter Lothberg &lt;<a =
href=3D"mailto:roll at Stupi.SE">roll at Stupi.SE</a>&gt; =
wrote:<br><br><blockquote type=3D"cite"><blockquote
type=3D"cite">On =
02/23/2013 07:21 PM, Cory Smelosky wrote:<br><blockquote =
type=3D"cite">I've managed to coax my provider in to giving me another =
IP<br>(apparently 5 IPs come with my plan=3D05), so I can get a virtual =
cisco<br>up on my VPS (in Canada).<br>=3D20<br>Brian, would you like to
=
get this all joined in to the mesh? &nbsp;Is a NA<br>hub still needed or =
has someone else offered one? (This'd be on an<br>unmetered gigE =
pipe)<br></blockquote>=3D20<br> I think running a hub on an emulated =
router maybe isn't the best idea.<br>(sorry to say =
so)<br></blockquote>=3D20<br>We also have to take in to account how to
=
get some kind of resonalble<br>routing, as the inside of an area is not =
exchanged with other =
areas.<br>=3D20<br>-P<br></blockquote><br></blockquote><br><br><br>---<br>=
Filter service subscribers can train this email as spam or not-spam =
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