[j-nsp] BGP Damping

[Joe Soricelli]

Both should work just fine as it's a policy and there are multiple ways
to match routes and set the damping parameters.

Like you said, the damping2 policy is going to need some terminating or
flow control actions in it! ;-)

-joe

> -----Original Message-----
> From: juniper-nsp-bounces at puck.nether.net 
> [mailto:juniper-nsp-bounces at puck.nether.net] On Behalf Of 
> Khawaja, Kashif
> Sent: Tuesday, August 10, 2004 8:13 PM
> To: juniper-nsp at puck.nether.net
> Subject: [j-nsp] BGP Damping
> 
> 
> Hi All:
> 
> Had a question about how damping policies can be written. 
> ##############################################################
> ##########
> ##
> Does a damping policy "have" to be of the following shape or 
> form i.e. prefix-lists/route-filters defined in the from 
> parts of the terms? 
> ##############################################################
> ##########
> ##
> 
> Borrowed from CYMRU's webpage for example:
> 
> [edit policy-options] 
> policy-statement damping {
> /* Do NOT dampen DNS root-servers */
>     term 1 {
>         from {
>             prefix-list root-servers.net;
>         }
>         then {
>             damping damp-none;
>             /* jump to next policy called */
>             next policy;
>         }
>     }
> /* Dampen according to prefix length.  */
> term 2 {
>     from {
>       /* Smallest penalty for /21 and smaller */
>             route-filter 0.0.0.0/0 upto /21 damping damp-short;
>       /* Medium penalty for /22 to /23 */
>             route-filter 0.0.0.0/0 upto /23 damping damp-medium;
>       /* Highest penalty for /24 and larger */
>       route-filter 0.0.0.0/0 orlonger damping damp-long;
>         }
>         then {
>             next policy;
>         }
>     }
> } 
> 
> ################################################################
> OR CAN IT ALSO LOOK LIKE THE NESTED POLICY BELOW? 
> ################################################################
> 
> policy-statement damping2 ( 
> term not-damp {
>     from policy no-damp; 
>     then damping do-not-damp;
> }
> term 24-and-bigger {
>     from policy 24-longer;
>     then damping damp-24;
> }
> term 22-and-23 {
>     from policy 22-to-23;
>     then damping damp-22;
> }
> term regular-damp {
>     then damping default-damp;
> }
> }
> 
> show policy-options policy-statement 24-longer 
> term one {
>     from {
>         route-filter 0.0.0.0/0 upto /23 next term;
>         route-filter 0.0.0.0/0 orlonger;
>     }
>     then accept;
> }
> term two {
>     then reject;
> }
> 
> show policy-options policy-statement 22-to-23    
> term one {
>     from {
>         route-filter 0.0.0.0/0 upto /21 next term;
>         route-filter 0.0.0.0/0 orlonger;
>     }
>     then accept;
> }
> term two {
>     then reject;
> }
> 
> show policy-options policy-statement no-damp
> term one {
>     from {
>         route-filter 1.1.1.0/24 exact accept;
>     }
>     }
> term two {
>     then reject;
> }
> 
> OF COURSE, add "then accept" or "then next policy" DEPENDING 
> ON WHERE IN THE LINE OF POLICIES THIS POLICY IS APPLIED TO 
> THE NEIGHBOR. 
> 
> Thanks.
> -Kashif.
> 
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