in
IEOC CCIE Forums

IEOC - INE's Online Community

Welcome to INE's Online Community - IEOC - a place for CCIE and CCENT candidates to connect, share, and learn. Our Online Community features CCIE forums and discussions for all tracks including Routing & Switching, Voice, Security, Service Provider, Wireless,, and Storage. Through these online communities you can discuss your questions with thousands of your peers, hundreds of CCIE's and INE's own team of world renowned CCIE instructors and authors, Brian Dennis - Quintuple CCIE #2210, Brian McGahan – Triple CCIE #8593, Petr Lapukhov - Quad CCIE #16379, and Mark Snow - Dual CCIE #14073.
Latest post 07-30-2016 3:29 PM by DarrellEscola. 5 replies.
Page 1 of 1 (6 items)
Sort Posts: Previous Next
  • 07-25-2016 4:30 AM

    7.2 Routing Policy

    This task asked for providing routing policy on the PE`s R8 and R7 using Communities tag to influence routing decission towards R9 routes ( the CE ) inside the MPLS cloud .

    After the policy has been successfuly applied R10 can reach R9 routes through R8 instead of R7  .

     

    However, R 10 does not retain the new LOCAL PREF value assigned by R8 because the prefix of R9 is moving to EBGP peer R10.

     

    MY question is , in the real word  can we use the community signaling method to influence the inbound traffic even if we are peering with two different providers ??

    thanks

     

    • Post Points: 35
  • 07-28-2016 10:31 PM In reply to

    Re: 7.2 Routing Policy

    i think so,  MED can be use but not if u have 2 different AS neighbors. so, community tags is what u have left if u are peering with two different providers.  

    Most if not all ISP will accept your community tag and have set up mapping for those so that traffic engineering becomes doable.

    • Post Points: 5
  • 07-29-2016 7:29 AM In reply to

    • peety
    • Top 25 Contributor
    • Joined on 02-23-2011
    • Redmond, WA, USA
    • Elite
    • Points 19,645

    Re: 7.2 Routing Policy

    Ibraheemo:

    MY question is , in the real word  can we use the community signaling method to influence the inbound traffic even if we are peering with two different providers ??

    Got dice? It's an absolute <insert a word here>shoot, for both MPLS and DIA. Some give great support, some give limited support, and I've even seen one DIA that appeared to intentionally strip all communities off, including well-known. Others refuse to accept MED.

    CCIE R&S #34583

    Now based in Redmond, WA

    • Post Points: 20
  • 07-29-2016 2:17 PM In reply to

    Re: 7.2 Routing Policy

    Thats the case that i have that even i use the communities to signal a local pref or MED for other values , then when the route leaves the AS ( provider next to my AS ) the attributes will be reset to it default ( local PREF 100 , and MED 0 ) or stripped off.

     

     

     

     

     

     

    • Post Points: 5
  • 07-30-2016 12:27 PM In reply to

    Re: 7.2 Routing Policy

    what is DIA ?  ISP ? not all will stripped or not communities; don't you ned some kind a agreement with ISP?

    • Post Points: 20
  • 07-30-2016 3:29 PM In reply to

    Re: 7.2 Routing Policy

    What Martin wrote is true - you can't control the incoming path - you can use community values or AS-Path prepending to REQUEST a particular path, but each ISP can have its own policies that may or may not respect your request.

    MED (or any other community value) is not necessarily sent/preserved betwen ISPs, so community values will not work unless you have an agreement with both ISPs that they will share your community values and will honor the community values in their path selection policy.

    Darrell A. Escola, B.Sc. IT
    MCSE, MCDBA, MCSD, Linux+

    • Post Points: 5
Page 1 of 1 (6 items)
IEOC CCIE Forums Internetwork Expert CCIE Training
About IEOC | Terms of Use | RSS | Privacy Policy
© 2010 Internetwork Expert, Inc. All Rights Reserved