[rbridge] Default Link Costs in base protocol -13

[Dinesh G Dutt]

Radia Perlman wrote:
> No objection, though perhaps if there are only a few (say less than 10) 
> different link speeds in common use,
> it might be useful to enumerate the default costs for each of those values.
>   
Doesn't IS-IS specify something like this already ? If it didn't, I'd 
probably stay with the formula used by IEEE in computing the link cost 
in spanning tree protocol unless there is a strong reason to change it.

Radia, it is not possible to enumerate primarily because of link 
aggregation because of which you can get various speeds.
> And, is it always obvious to a zero configuration Rbridge what speed 
> each of its ports is?
>   
Yes.

Dinesh
> Radia
>
> Donald Eastlake wrote:
>   
>> Hi,
>>
>> I'm thinking that something like this should be added to item 1 in
>> section 4.2.4.4 of the base protocol draft version -13:
>>
>>
>> To facilitate efficient zero configuration operation, RBridges SHOULD,
>> by default, set the cost of a link to one trillion (1,000,000,000,000)
>> diviided by the RBridge port's bit rate rounded to the nearest value
>> that will fit in the wide metric; for example, the cost for a
>> link accessed by a 1Gbps port would default to 1,000. However, the
>> cost MAY, by default, be increased if the link appears to be a bridged LAN.
>>
>>
>> Thanks,
>> Donald
>> =============================
>>  Donald E. Eastlake 3rd   +1-508-634-2066 (home)
>>  155 Beaver Street
>>  Milford, MA 01757 USA
>>  d3e3e3 at gmail.com
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>>     
>
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