pref syntax for RIPE-81++ (fwd)

Jessica prepared this several weeks ago, and it got stuck in my
mail queue.  My apologies to RIPE and Jessica for holding this up.
        --Elise

Forwarded message:
> -------------------
>  
> interas-in and interas-out preference definition
> 
> 1. interas-in
> 
> interas-in: [from] neighborAS preference [accept] route
> 
> where 'preference' here is defined as:
> 
> <pref-type>=<value> [,<pref-type>=<value>]
> 
> <pref-type> has the following:
> 
> 	pref: 	the pre-configured preference for incoming routes same as 
> 		defined in as-in attribute.  It's value is numeric number.
> 		The lower the value, the higher preference.
> 
> 	med-in:	the usage of Multi_Exit_Discriminator metric from its 
> 		neighbor's routing advertisement.  The value is yes or no.
> 		Omission of the entry implies no usage of  MED from its
> 		neighbor AS.
> 
> 2. interas-out
> 
> 	interas-out: [TO] neighborAS preference [ANNOUNCE] route  
> 
> where 'preference' is defined as:
> 
> <pref-type>=<value> [,<pref-type>=<value>] 
> 
> <pref-type> has the following: 
> 
>         pref:   the pre-configured preference for outgoing routes same as 
> 		defined in interas-in attribute.  It's value is numeric 
>                 number.  The lower the value, the higher preference. 
> 
>         med-out: the value of Multi_Exit_Discriminator metric to advertise 
> 		routes to neighborAS.  If IGP metric is used to convert to 
> 		MED, the value is 'IGP'.  Otherwise, the value is a numeric
> 		number.  Omission of the entry implies no usage of MED when
>                 advertising routes to its neighbor AS.
> 
> 3. Examples:
> 
> aut-num: AS237
> interas-out: to AS690 <enss128> med-out=IGP announce AS237
> interas-out: to AS690 <enss145> med-out=IGP announce AS237
> 
> aut-num: AS266 
> interas-out: to AS690 <enss131> pref=1 announce {35/8, 128.14/16}
> interas-out: to AS690 <enss129> pref=2 announce {35/8, 128.14/16}  
> 
> aut-num: AS701
> 
> interas-out: to AS690 <enss134> med-out=2 announce {15/8,192.35.1/24}
> interas-out: to AS690 <enss145> med-out=4 announce {15/8,192.35.1/24, 193.1.1/24}
> 
> aut-num: AS690
> interas-in: from AS237 med-in=yes accept AS237
> 
> interas-in: <enss131> from AS266 pref=1 accept {35/8, 128.146/16}
> interas-in: <enss129> from AS266 pref=2 accept {35/8, 128.146/16}
> 
> interas-in: from AS701 med-in=yes accept ANY 
> 
> 4. Expansion
> 
> The preference field by this design could be easily expanded in the future
> when other metrics be used for policy decisions without changes to the already
> defined ones.  For example, when tos/qos is widely used, one could just add
> another field in the pref-type: tos=value.
> 
> 
> 




-------- Logged at  Wed Jul 13 23:26:03 MET DST 1994  ---------