[j-nsp] cgnat on service module - interesting bgp advertisements

[Alexander Arseniev]

Hello,
MS-MIC (and MS-MPC NPUs as well) automatically cuts out network (in your 
case .128) and broadcast (in your case .255) IPs.
The rest cannot be expressed as single prefix, hence a bunch of smaller 
prefixes is annonced instead.
This was done as PR 1019354 fix
https://prsearch.juniper.net/InfoCenter/index?page=prcontent&id=PR1019354
HTH
Thx
Alex

On 20/04/2016 00:48, Aaron wrote:
> Very interesting. anyone know why this is happening ?  Is this documented ?
> I put a /25 as the public nat pool, but look what this mx104 is advertising
> via bgp.. It appears to chop up that /25 into a bunch of smaller subnets and
> advertise those out
>
>   
>
>   
>
> agould at eng-lab-mx104-cgn> show configuration | grep 1.2.3. | display set
>
> set services nat pool nat1 address 1.2.3.128/25
>
>   
>
>   
>
> agould at eng-lab-mx104-cgn> show route advertising-protocol bgp 10.101.0.2
> table one.inet.0
>
>   
>
> one.inet.0: 782 destinations, 970 routes (782 active, 0 holddown, 0 hidden)
>
>    Prefix                  Nexthop              MED     Lclpref    AS path
>
> * 10.144.2.4/30           Self                         100        I
>
> * 1.2.3.129/32         Self                         100        I
>
> * 1.2.3.130/31         Self                         100        I
>
> * 1.2.3.132/30         Self                         100        I
>
> * 1.2.3.136/29         Self                         100        I
>
> * 1.2.3.144/28         Self                         100        I
>
> * 1.2.3.160/27         Self                         100        I
>
> * 1.2.3.192/27         Self                         100        I
>
> * 1.2.3.224/28         Self                         100        I
>
> * 1.2.3.240/29         Self                         100        I
>
> * 1.2.3.248/30         Self                         100        I
>
> * 1.2.3.252/31         Self                         100        I
>
> * 1.2.3.254/32         Self                         100        I
>
>   
>
>   
>
> Aaron
>
>   
>
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