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jay
Post  Post subject: BGP question  |  Posted: Thu Jun 02, 2016 1:14 pm

Joined: Wed Jun 01, 2016 11:06 am
Posts: 3

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BGP question

Hello Everyone,

i have situation where i'm receiving a /26 subnet via CPE router and i only want to advertise /29 subnet to EBGP. is there any way to do that? i can't advertise whole /26 as it breaks other customer. Note: /29 prefix does not live on the box so i can't advertise them directly. Any help would be highly appreciated.

Note: Using Juniper MX box

so far what i did is

static {
route 24.206.51.32/29 {
receive;
no-install;
}
}
So the /29 would be in RIB but not used for forwarding decisions. i advertised /29 prefix from RIB to EBGP. but would /29 never advertised-------> didn't work this solution.

2nd try.

I create static /29 route point toward CPE and advertised /29 prefix to ebgp but again would never advertised----> didn't work

Thanks,
Jay





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admin
Post  Post subject: Re: BGP question  |  Posted: Thu Jun 02, 2016 3:50 pm
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SOmething you're not doing right. On 1st try (first options), do a "show route advertising-protocol bgp <neighbor IP>".
I assume you have proper export policies in place, don't you ?

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admin
Post  Post subject: Re: BGP question  |  Posted: Thu Jun 02, 2016 3:53 pm
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Also give up the "receive" keyword. It will instruct the PFE to send all transit traffic for that route to the routing engine and, trust me, you don't want that.

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admin
Post  Post subject: Re: BGP question  |  Posted: Thu Jun 02, 2016 3:57 pm
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http://www.juniper.net/documentation/en_US/junos15.1/topics/reference/configuration-statement/static-edit-routing-options.html
Quote:
receive—Install a route for this next-hop destination into the routing table.
The receive option forces the packet to be sent to the Routing Engine.

The receive option can be useful in the following cases:

For receiving MPLS packets destined to a VRF instance's loopback address
For receiving packets on a link's subnet address, with zeros in the host portion of the address

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jay
Post  Post subject: Re: BGP question  |  Posted: Fri Jun 03, 2016 10:20 am

Joined: Wed Jun 01, 2016 11:06 am
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Yes i do have proper export policy.

show route protocol bgp advertising-protocol bgp 22.172.67.162

CPE-MGMT.L3VPN.inet.0: 13093 destinations, 26217 routes (13093 active, 0 holddown, 0 hidden)
Prefix Nexthop MED Lclpref AS path
* 22.42.182.0/25 Self 7843 20001 I
* 22.141.178.0/24 Self 7843 10796 I
* 22.205.63.0/24 Self I
* 22.212.194.0/24 Self 7843 11351 I
* 51.83.225.0/24 Self 7843 11427 I

I gave up receive command as well but it would never advertised to ebgp peer.


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jay
Post  Post subject: Re: BGP question  |  Posted: Fri Jun 03, 2016 10:34 am

Joined: Wed Jun 01, 2016 11:06 am
Posts: 3

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Yes i do have proper export policy. i gave up "receive" keyword and try to advertise again but it would never advertise to ebgp peer.

show route protocol bgp advertising-protocol bgp 22.172.57.161

CPE.L3VPN.inet.0: 19033 destinations, 21627 routes (19033 active, 0 holddown, 0 hidden)
Prefix Nexthop MED Lclpref AS path
* 22.33.172.0/25 Self 3487 40001 I
* 22.132.168.0/24 Self 3487 10697 I
* 22.206.53.0/24 Self I
* 22.203.184.0/24 Self 3487 15311 I
* 52.74.205.0/24 Self 3487 11247 I


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admin
Post  Post subject: Re: BGP question  |  Posted: Fri Jun 03, 2016 11:54 am
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Please post your bgp configuration, export policy as well as routing-options for the relevant VRF.

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