From: Charles Church (cchurch@wamnet.com)
Date: Thu Aug 14 2003 - 11:58:49 GMT-3
Cal,
What kind of dial up circuits are you using that have a BW of 6kbps? Are
they tunnel interfaces? I agree though that 10000 can cause come problems
at the bottom end. Since 10 gig will probably only exist in the core, using
a smaller number (somewhere between 300 and 1000) might prove better. You
can always adjust the cost (or BW) on those core interfaces that end up
needing it.
Chuck Church
CCIE #8776, MCNE, MCSE
Wam!Net Government Services
13665 Dulles Technology Dr. Ste 250
Herndon, VA 20171
Office: 703-480-2569
Cell: 703-819-3495
cchurch@wamnet.com
PGP key: http://pgp.mit.edu:11371/pks/lookup?search=chuck+church&op=index
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Cal Michael
Sent: Tuesday, August 12, 2003 4:13 PM
To: ccielab@groupstudy.com
Cc: jfaure@sztele.com
Subject: RE: OSPF - Reference Bandwidth
- All,
We had introduced this to a enterprise
sized network about two years ago, and
until now, all seemed all right.
I might be missing something important
or I may not; but I have to verify if
what I think I know is really accurate.
My knowledge is that if all links are
in OSPF, and have a common reference
bandwidth, then the algorithm will
take care of the rest. . .
Here is the original issue (sanitized):
"Since switching to 10000 as our OSPF
reference bandwidth, we have had troubles
with 'normal' multi-homed sites routing
in OSPF. The most recent example is BU
"X". The dial backup and WAN link at
these sites should be able to coexist
based on bandwidth. They cannot as the
OSPF metric 10000 'bottoms out' at 160KB.
A dial-backup usually has a BW value of
6. Our current metric was designed to
allow for the use of 10G interfaces -
which we do not have. I played with the
numbers, and found the 325 seemed to
produce the closest to a balanced result.
Using 325 as a reference bandwidth yields
the following costs as listed below, and
allows the use of bandwidth values down
to 5.
Gigabit 1
OC3 2
FastEthernet 3
DS3 7
BW 30000 10 Head End to BU "A"
TokenRing16 20
Ethernet 32
BW 9200 35 Head End to BU "B"
TokenRing4 81
BW 3000 108 Head End to BU "B"
T-1 210
128K 2539
Analog Dial - 6 54166
There are parts of the network now that
require manual costing of interfaces to
get desired results. I would like to see
us be able to go back to bandwidth and
simplify the process again. Please review
these figures and see if they work in your
situations."
The logic just doesn't make sense, but
out of all the minds and experience out
there, one of you may have seen something
similar (grin).
--- Thanks ---
-----Original Message-----
From: jfaure@sztele.com [mailto:jfaure@sztele.com]
Sent: Tuesday, August 12, 2003 12:42 PM
To: Cal Michael
Cc: ccielab@groupstudy.com; nobody@groupstudy.com
Subject: Re: OSPF - Reference Bandwidth
Hi:
We're using your same "exact reference bandwith" (10000) in one of our
customers network since 2 years ago, and we haven't seen any ospf problem,
neither with dial backup nor other issues. (And this is a very big network
with hundreds of routers). What's your problem?
Remember you must put this Reference Bandwith in ALL the routers speaking
OSPF
Regards
Juan Faure Ferrer
email: jfaure@sztele.com
Lmnea de Negocio de Telematica y CC
Ingeniero de Integracisn de Redes y Sistemas
----------------------------------------------------------------------------
SOLUZIONA TELECOMUNICACIONES
Servicios Profesionales de UNION FENOSA
Jerez, 3
28016 MADRID
tel 91 579 30 00 fax 91 350 72 83
---------------------------------------------------------------------------
"Cal Michael"
<cmichael@network Para: <ccielab@groupstudy.com>
-data.com> cc:
Enviado por: Asunto: OSPF - Reference
Bandwidth
nobody@groupstudy
.com
12/08/03 19:23
Por favor,
responda a "Cal
Michael"
- All,
Is anyone using alternate OSPF reference
bandwidths in production so that OSPF can
differentiate between WAN/MAN links that
are greater than 100mb (default reference)?
If so, do you have any issues with using
a reference bandwidth equal or greater than
10000 (10Gig) and dial backup technologies?
--- Thanks ---
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