[j-nsp] vrf-target vs route-target

[senad palislamovic]

Hamid,

  1) The difference between a route-target and vrf-target. what i know is that for route target 
  we need to enable Border Gateway Protocol (BGP) route target filtering on the Layer 3 VPN.

sp>

Route-target is another NLRI family based on the following draft:

http://tools.ietf.org/html/draft-marques-ppvpn-rt-constrain-01

It allows RRs and PEs to minimize their route advertisements to "ONLY" interested VPNs, defined through route-target BGP extended community.

vrf-target, a config-knob within VRF, allows single statement to be used for importing and exporting routes into VRF.  You can actually have all of the following:

vrf-export [ policy-names ];
vrf-import [ policy-names ];
vrf-target (community | export community-name| import community-name);

They all in a sense can accomplish the same thing.  Please look at the following link:

http://www.juniper.net/techpubs/software/junos/junos84/swconfig84-vpns/swconfig84-vpns.pdf


 2) are these two statements used in place of each other or can be used together?

sp>
Nope.  They do different things.  One is importing/exporting routes into/from VRF.  Other negotiates which routes to be advertised in specific MP-BGP peering, based on each router's interest.

) What are the situations when one statement can be preferred over the other?

sp>

Never

 4) Also can anyone clearly specify interaction between inet.0; inet.3 and bgpl3.vpn routing tables. Just to inshort what is the protocol flow and routing-advertisement flow from one end to other[ the situation is that there are ce-pe routers at both ends with MPLS running in   between]
  
Inet.0 hold all regular non-labeled routes, so your IGP or BGP routes.  Inet.3 hold only MPLS capable labeled routes; derived most commonly through LDP or RSVP.  Modifications of all of it is possible, based on certain design criteria.  In simple, default L3VPN single-as scenario, inet.3 hold routes to Ps' and PEs' loopbacks.   bgp.l3vpn.0 actually holds customer "VPN" routes in the form of RD:Prefix.  

Please read the paper found at the following link for more in-debth information about all gotchas of L3VPN configs on JUNOS.  Once you go through it, you will find the documentation very useful.

http://www.juniper.net/techpubs/software/junos/junos84/swconfig84-vpns/swconfig84-vpns.pdf

HTH and let us know if you have any other questions...

Regards,

Senad

----- Original Message ----
From: Hamid Ahmed <hamidahmed77 at yahoo.com>
To: Juniper List <juniper-nsp at puck.nether.net>
Sent: Wednesday, November 14, 2007 10:37:25 AM
Subject: [j-nsp] vrf-target vs route-target

Hi Everyone,
  
  I would like to know:
  
  1) The difference between a route-target and vrf-target. what i know is that for route target 
  we need to enable Border Gateway Protocol (BGP) route target filtering on the Layer 3 VPN.
  2) are these two statements used in place of each other or can be used together?
  3) What are the situations when one statement can be preferred over the other?
  4) Also can anyone clearly specify interaction between inet.0; inet.3 and bgpl3.vpn routing tables. Just to inshort what is the protocol flow and routing-advertisement flow from one end to other[ the situation is that there are ce-pe routers at both ends with MPLS running in   between]
  
  I find some documentation on Juniper little bit tricky and confusing. Specfically i need to know when a packet traverses from a PE/CE router to the other end to a VRF what and how does BGP, RSVP and IGP play inbetween keeping in mind the workin of inet.0, inet.3 bgpL3.vpn routing tables.
  
  Best regards,
  HA

      
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