Re: [Isis-wg] draft-eastlake-isis-trill-00.txt

[mike shand <[e-mail]>]

I agree with Donald that we don't want to unnecessarily burn the TLV 
codespace, and that the overhead of the occasional large sub-TLV within 
a TLV is not significant.

     Mike


On 25/06/2010 03:56, Donald Eastlake wrote:
> Hi Vishwas,
>
> On Sun, Jun 20, 2010 at 11:13 PM, Vishwas Manral<[e-mail]>  wrote:
>    
>> Hi Don,
>>
>> I had a cursory look at the draft.
>>
>> I thought there was one issue you need to consider which might change the
>> shape of the draft itself. Unlike all other protocols IS-IS TLV’s has a
>> length field of only 8 bits which means that having sub-TLV’s which are very
>> big is not preferred. Seeing the size of sub-TLV’s defined it seems we will
>> as well need different TLV’s for each sub-TLV. I would think it is better to
>> define them as separate TLV’s.
>>      
> Thanks for your comment. I guess it would be nice for TRILL if some or
> all of the proposed sub-TLVs were TLVs. But TLV types are a limited
> resource.
>
> I've done a scan of the draft. I don't see any problem with the fixed
> length sub-TLVs, which are small. They should fit fine within the TLV
> specified to contain them. There are also a number of variable length
> sub-TLVs. But I believe that, in many cases, these variable length
> sub-TLVs will be fairly short. And in cases where they are larger,
> perhaps not fitting in a single enclosing TLV, the enclosing TLV can
> be repeated and I don't think the two bytes of overhead per repetition
> are a big deal.
>
> So, if there is a consensus to change one or more of these sub-TLVs to
> TVLs, I'd be happy to do that. Otherwise, I don't plan to make such
> changes.
>
>    
>> Have a look at the TE related TLV’s. You will notice that SRLG is a separate
>> TLV in itself (if memory serves me right). Let me go through the draft and
>> give you information about the content itself.
>>      
> SRLG? RFC 5305 specified three TLVs:
>        Extended IS Reachability
>        Traffic Engineering Router ID
>        Extended IP Reachability
>
>    
>> Thanks,
>> Vishwas
>>      
> Thanks,
> Donald
>
>    
>> ________________________________
>>
>> From: [e-mail] [mailto:[e-mail]] On Behalf
>> Of Donald Eastlake
>> Sent: Sunday, June 20, 2010 7:32 PM
>> To: isis mailing list
>> Subject: Re: [Isis-wg] draft-eastlake-isis-trill-00.txt
>>
>>
>>
>> A error has been pointed out on the TRILL WG mailing list:
>>
>> In Section 2.5, Page 17, Length is "1 + 9*n" not "2 + 9*n".
>>
>>
>>
>> Thanks,
>>
>> Donald
>>
>> On Fri, Jun 11, 2010 at 1:53 PM, Donald Eastlake<[e-mail]>  wrote:
>>
>> Hi,
>>
>>
>>
>> I've submitted a draft proposing IS-IS support for TRILL:
>>
>> http://tools.ietf.org/html/draft-eastlake-isis-trill-00
>>
>> Thanks,
>>
>> Donald
>>
>> =============================
>> Donald E. Eastlake 3rd   [phone] (cell)
>> 155 Beaver Street
>> Milford, MA 01757 USA
>> [e-mail]
>>
>>
>>      
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>    

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