From: Carlos G Mendioroz (tron@huapi.ba.ar)
Date: Sun Jul 11 2004 - 19:47:29 GMT-3
Ty,
I don't follow you. Precedence is only 3 bits, not 7.
Prec - ToS
7 E0 1110 0000
6 C0 1100 0000
5 A0 1010 0000
4 80 1000 0000
3 60 0110 0000
2 40 0100 0000
1 20 0010 0000
0 00 0000 0000
Ty wrote:
> correct, but the formula that I am using is correct too...just easier
>
> precednce only has bits 0-7
> prec 0 = ToS 00
>
> 0 0 0 0 0 0 0 0
> E C A 8 4 2 1
>
> I am counting over from right to left...if ip prec is 7 then 7 over from
> right to left is 0 1 0 0 0 0 0 0
>
> ie
>
> prec 7
> Tos 0100 0000 ( counting from right to left...that would be bit 7)
> tos = E0
>
> prec 4
> Tos 0000 1000
> tos = 08
>
> prec 5
> ToS 0001 0000
> tos = A0
>
> formula still works the same way...just looks different :-)
>
> I'm just doing the math a little differently....it ends up coming out the
> same way...no matter which method you use
>
> ----- Original Message -----
> From: "Carlos G Mendioroz" <tron@huapi.ba.ar>
> To: <barrerj1@hotmail.com>
> Cc: "'Ty'" <tycampbell@comcast.net>; <ccielab@groupstudy.com>
> Sent: Sunday, July 11, 2004 5:17 PM
> Subject: Re: tos values
>
>
>
>>Ty,
>>ToS byte is used in two different ways:
>>
>>PPPDTRUU like 3 bits for precedence, some flags and unused bits.
>>
>>or (new style)
>>
>>DDDDDDEE like 6 bits for DSCP code and 2 bits for ECN (explicit
>>congestion notification).
>>
>>Precedence 5 would be 101 in binary, so it would end being 10100000, or
>>A0 (as you said) but because bits are:
>>
>> 1 0 1 0 0 0 0 0
>>*8 4 2 1 8 4 2 1
>>=8 0 2 0 0 0 0 0
>> A 0
>>
>>cause 8 + 2 = A
>>
>>Precedence 7 would be
>>
>> 1 1 1 0 0 0 0 0
>> E 0
>>
>>barrerj1@hotmail.com wrote:
>>
>>
>>>Thanks for the info and for taking time to go over the details,
>>>
>>>
>>>JB
>>>
>>>-----Original Message-----
>>>From: Ty [mailto:tycampbell@comcast.net]
>>>Sent: Sunday, July 11, 2004 3:43 PM
>>>To: ccielab@groupstudy.com; barrerj1@hotmail.com
>>>Subject: Re: tos values
>>>
>>>I couldn't find it, but I did figure it
>>>
>>>it works like this..
>>>
>>>say the ip precedece is 5 and you want to conver it to ToS
>>>
>>>ToS uses 8 bits in hex ie 00000000 split into 2 parts 0000 0000
>>>
>>>ip precedence is 5 ..so that would be the fifth bit in ToS which would
>>>equal 0001 0000
>>>
>>>beaking down the ToS bits 0 0 0 0 0 0 0 0
>>> E C A 8 4 2
>>>1
>>>
>>>there is not a match to worry about for the 8th bit, as ip precedence
>>>only
>>>goes to 7
>>>
>>>R7(config)#access-list 107 permit ip any any precedence ?
>>> <0-7> Precedence value
>>> critical Match packets with critical precedence (5)
>>> flash Match packets with flash precedence (3)
>>> flash-override Match packets with flash override precedence (4)
>>> immediate Match packets with immediate precedence (2)
>>> internet Match packets with internetwork control precedence (6)
>>> network Match packets with network control precedence (7)
>>> priority Match packets with priority precedence (1)
>>> routine Match packets with routine precedence (0)
>>>
>>>going back to ip precedence of 5 would equal 0001 0000 in ToS
>>>
>>>therefore the ToS of A0 would equal an ip precendece of 5
>>>
>>>another example... ip precedence of 7 would equal ToS E0
>>>
>>>7 = 0100 0000
>>>----- Original Message -----
>>>From: <barrerj1@hotmail.com>
>>>To: "'Ty'" <tycampbell@comcast.net>
>>>Sent: Sunday, July 11, 2004 3:10 PM
>>>Subject: RE: tos values
>>>
>>>
>>>
>>>
>>>>Can you tell me where you find the info?
>>>>
>>>>Thanks
>>>>JB
>>>>
>>>>
>>>>
>>>>-----Original Message-----
>>>>From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
>>>
>>>Of
>>>
>>>
>>>>Ty
>>>>Sent: Sunday, July 11, 2004 3:04 PM
>>>>To: Ty; ccielab@groupstudy.com
>>>>Subject: Re: tos values
>>>>
>>>>I figured it out
>>>>
>>>>tos is done in hex
>>>>
>>>>so if and ip precednce of 5 were to be converted to tos then it would
>>>
>>>be
>>>
>>>
>>>>00010000 in hex...this would make the tos A0
>>>>
>>>>Thanks!!
>>>>
>>>>
>>>>
>>>>----- Original Message -----
>>>>From: "Ty" <tycampbell@comcast.net>
>>>>To: <ccielab@groupstudy.com>
>>>>Sent: Sunday, July 11, 2004 2:55 PM
>>>>Subject: tos values
>>>>
>>>>
>>>>
>>>>
>>>>>I have searched the DOC CD, but cannot find a formula or table to
>>>>
>>>>convert
>>>>ip
>>>>
>>>>
>>>>>precedence values to tos.
>>>>>Does anyone know where this is on the DOC CD ?
>>>>>
>>>>>Thanks!!
>>>>>
>>>>>
>>>>
>>>_______________________________________________________________________
>>>
>>>
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>>>>
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>>>>
>>>>
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>>>>
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>>>
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>>>Please help support GroupStudy by purchasing your study materials from:
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>>
>>--
>>Carlos G Mendioroz <tron@huapi.ba.ar> LW7 EQI Argentina
>>
>
>
>
-- Carlos G Mendioroz <tron@huapi.ba.ar> LW7 EQI Argentina
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