4 comments on “TAC Tales #4: Airline Outage

  1. Hello ccie14023,

    I have read several articles from you and they are quite interesting. I have one question which I did not find any related information sw. so I thought about you.

    I am not sure whether you come here often, I just hope you will see it and get me a hint.

    The question is about PE-CE ospf backdoor in MPLS L3VPN topic. I read from Juniper study guides, it is written,

    to ” ensure that the PE router’s OSPF-to-IBGP export policy matches OSPF routes originated from the local site and rejects any OSPF routes heard through the legacy backbone”

    my question is, how to achieve this ? should I use prefix-list to match the routes generated from local site, or there is other elegant way ? for example advertising router id ?

    The reason why I ask is, in the following topology
    PE1——–PE2
    | |
    CE1——–CE2

    PE1 and CE1 belongs to site1, PE2 and CE2 belong to site2. PE1 and PE2 should generate type 5 lsa, and mpls backbone should be backup of Backdoor between CE1 and CE2.

    I have configured different domain-id, and ospf preference 180. but anyway, it happens very often that I see one of the PE have all ospf routes, and the other has bgp routes. I think the reason is I did not control which ospf routes should be advertised by vrf-export policy as written in Juniper study guide.

    but anyway, nothing is written in this study guide how to control them. I suppose we can only do prefix list to match those routes which are generate from local sites. nothing else we can do, is that correct ?

    Thank you very much in advance!
    BR.
    Sara

  2. anyway, it can not be shown in the correct way. the links are between PE1 and CE1, PE2 and CE2, and between CE1 and CE2 there is also backdoor. but every time after I posted, the 2 links will be beside each other.

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