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Latest post 12-20-2016 9:29 PM by SamarjitAdhikari. 6 replies.
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  • 12-19-2016 9:24 PM

    Want to verify self understanding of RD/RT in L2/L3 MPLS VPN context

    Hello experts,

    I am a new member of INE and read about couple of courses on RD/RT BGP router configuration.

    My query is on following simple topology 

    CE1--> PE1<--------> PE2 -->CE2

    My understanding is that RD is used to distinguish different VPNs/Customers on a PE so that same IP address could be used in 2 different VPNs/customer sites on same PE. Now the RT is used to uniquely identify the right VRF for that VPN/customer to forward packet on other side. If an iBGP update travel from PE1 toPE2 , the first thing PE2 does is to stripped of the RD and based on RT information any labeled MPLS packets will be put into right VRF to deliver to CE2. 

    In the above scenario the RT needed to be unique across all PEs. Is my understanding correct?

    With regards,

     

    Samarjit

    Filed under:
    • Post Points: 20
  • 12-19-2016 9:50 PM In reply to

    Re: Want to verify self understanding of RD/RT in L2/L3 MPLS VPN context

    Hi,

    RT is used to control import/export routes on PE routers, if you export RT 100:100 on VRF_A, the remote PE should import same RT value to get VRF_A routes installed in the routing table.

    HTH

    • Post Points: 20
  • 12-19-2016 10:11 PM In reply to

    Re: Want to verify self understanding of RD/RT in L2/L3 MPLS VPN context

    Hi,

    Thanks for replying. Thus if a PE has 2000 VRFs, we require 2000 unique RT values both on local PE and remote PE to identify the same route instances. ?

    With regards,

    Samarjit

    • Post Points: 20
  • 12-19-2016 10:25 PM In reply to

    Re: Want to verify self understanding of RD/RT in L2/L3 MPLS VPN context

    Import/Export RTs can be similar in some instances but if you were to seperate your customers with VRFs, you would need different RT values per VRF. 

    • Post Points: 20
  • 12-19-2016 10:48 PM In reply to

    Re: Want to verify self understanding of RD/RT in L2/L3 MPLS VPN context

    Ok, thats great. 

    Now there is another scenario. 

    Lets assume Customer-A wants 2 different VPLS instances for its' HR and Enginerring departments. Is it require to create 2 different VRF for same customer? 

    With regards,

    Samarjit

    • Post Points: 20
  • 12-20-2016 7:36 AM In reply to

    Re: Want to verify self understanding of RD/RT in L2/L3 MPLS VPN context

    Hi, 

    If you are referring to Cisco's VPLS implementation, you would need to have two seperate VPLS bridge domains to fulfill your requirement. 

    If you are referring to the L3VPN scenario, it would need to have two VRFs to segregate two different services. 

    HTH

    • Post Points: 20
  • 12-20-2016 9:29 PM In reply to

    Re: Want to verify self understanding of RD/RT in L2/L3 MPLS VPN context

    Thanks a lot. 

    Could you please provide configuration steps for

    1. Two VPLS bridge domains for L2 VPN and 

    2. Two VRF configuration for L3VPN? 

    Any good reference for doing the above configuration also works for me. 

    With regards,

    Samarjit

    • Post Points: 5
Page 1 of 1 (7 items)
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