Re: Cost to the Root Bridge 10^9/Bandwidth ?

2000-06-07 Thread Edward Solomon

The costs have recently been altered. This is reflected in the Cisco
Catalyst switch IOS (except the 1900 series).

Link Speed  Cost (reratified IEEE spec)   Cost (previous IEEE spec)
---
10 Gbps   2 1
1 Gbps4 1
100 Mbps 1910
10 Mbps 100   100


--

Edward Solomon
CCNA, CCSI
Senior I/T Specialist
Networking Solutions
IBM Canada Ltd. - Learning Services
Tel.: (905) 316-3241  Fax: (905) 316-3101
E-mail: [EMAIL PROTECTED]
Internet: http://www.can.ibm.com/services/learning/net_internet.html

"Phil Barker" <[EMAIL PROTECTED]> wrote in message
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> Hi,
>Just happened on this studying for CIT.
>
> Looking at how Root bridges calculate their respective
> costs using 10^9/Bandwidth.
> If the BW = 100Mbit/s then the cost = 10 i.e
> 10^9/100*10^6 = 10.
>
> Presumably if using a Gigabit link to root then the
> cost would be 1.
>
> My question is what will happen when Terrabit comes on
> board ? if this answer is < 1. Will the output be in
> floating point notation or will it be rounded to the
> nearest integer ?
>
> A cost of root of 0 and a cost to root of 0 could be
> confusing.
>
> Can anyone with a lab do a test with an E1/T1 link to
> verify the output ? I would myself but i'm 130 miles
> away from my lab.
>
> I get E1 = 488.28125 on paper.
> and T1 = 647.6684 for T1
>
> Does the output just show as integer or as a float ?
>
> Phil.
>
>
>
> 
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Re: Cost to the Root Bridge 10^9/Bandwidth ?

2000-06-07 Thread Phil Barker

Cripes !!!
 Thanx for the reply. 

So it looks like we have potential "Spanking Tree"
problems ahead. We are already rolling with Cat
6000/3500 into our new sites, so any old kit goes in
would mean that "spanking Tree" would not be
calculated  correctly and could go "Loop the Loop".

Phil.

--- Edward Solomon <[EMAIL PROTECTED]> wrote: > The
costs have recently been altered. This is
> reflected in the Cisco
> Catalyst switch IOS (except the 1900 series).
> 
> Link Speed  Cost (reratified IEEE spec)   Cost
> (previous IEEE spec)
>
---
> 10 Gbps   2 1
> 1 Gbps4 1
> 100 Mbps 1910
> 10 Mbps 100   100
> 
> 
> --
> 
> Edward Solomon
> CCNA, CCSI
> Senior I/T Specialist
> Networking Solutions
> IBM Canada Ltd. - Learning Services
> Tel.: (905) 316-3241  Fax: (905) 316-3101
> E-mail: [EMAIL PROTECTED]
> Internet:
>
http://www.can.ibm.com/services/learning/net_internet.html
> 
> "Phil Barker" <[EMAIL PROTECTED]> wrote in
> message
>
[EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> > Hi,
> >Just happened on this studying for CIT.
> >
> > Looking at how Root bridges calculate their
> respective
> > costs using 10^9/Bandwidth.
> > If the BW = 100Mbit/s then the cost = 10 i.e
> > 10^9/100*10^6 = 10.
> >
> > Presumably if using a Gigabit link to root then
> the
> > cost would be 1.
> >
> > My question is what will happen when Terrabit
> comes on
> > board ? if this answer is < 1. Will the output be
> in
> > floating point notation or will it be rounded to
> the
> > nearest integer ?
> >
> > A cost of root of 0 and a cost to root of 0 could
> be
> > confusing.
> >
> > Can anyone with a lab do a test with an E1/T1 link
> to
> > verify the output ? I would myself but i'm 130
> miles
> > away from my lab.
> >
> > I get E1 = 488.28125 on paper.
> > and T1 = 647.6684 for T1
> >
> > Does the output just show as integer or as a float
> ?
> >
> > Phil.
> >
> >
> >
> >
>

> > Do You Yahoo!?
> > Get your free @yahoo.co.uk address at
> http://mail.yahoo.co.uk
> > or your free @yahoo.ie address at
> http://mail.yahoo.ie
> >
> > ___
> > UPDATED Posting Guidelines:
> http://www.groupstudy.com/list/guide.html
> > FAQ, list archives, and subscription info:
> http://www.groupstudy.com
> > Report misconduct and Nondisclosure violations to
> [EMAIL PROTECTED]
> > ---
> 
> 
> ___
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[EMAIL PROTECTED]



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Get your free @yahoo.co.uk address at http://mail.yahoo.co.uk
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