Lab 3 - 4.3 Question

Just double checking my workings against the INE provided solutions in Lab 3 / 4.3

In the solutions guide shouldn't the peerings between XR1 and R2 be BGP+label (labeled unicast) and same for R3 to R4 ebgp (BGP+label)?

 

In the solutions there is no mention of "send-label" or "ipv4 labeled-unicast" XR side.

-v10d

 

Comments

  • Option-B does not require send-label between eBGP peers; they have VPNv4 eBGP peers and labels are sent along with prefixes.

    AB.

  • It depends on how your learn your prefix. If you are learning AS3719 prefixes in to AS248 (they right?) via BGP then you must have a BGP label. 

  • It depends on how your learn your prefix. If you are learning AS3719 prefixes in to AS248 (they right?) via BGP then you must have a BGP label. 

     

    Right but it's what Amit stated.  I overlooked the fact that it was just a vpnv4 peering and not any IPv4.  So no unicast labeling is required for Opt B.

    -v10d

     

  • Unless you use bgp+label internally in your AS :)

    i don't remember the specifics of the lab

  • @void64

    yes should be bgp+label ,but not for ipv4 on 2 ebgp links xr1 and r2 and other link r3 and r4. in option B vpn peering and lable are handle by vpnv4 configuration on ebgp links , so when you configure ebgp links as a vpnv4 then  lable will be autogenerated on the link for bgp , a log message will come to console if iam not wrong

     

    shaikh

  • No BGP+ Labels in that lab but a big headache 4 me [:(] .. i got a loop so big who is still letting me turn around. I did check the solution in lab 3 which INE provided and i did the config well. I just did not get tonight from where the loop was coming from. I was going to perform route tagging when my 6 hours session expired. 

     

    what you guys used to detect the loop?

    Alessio

     

     

     

  • Where did you see your loop? Shouldn't be one in the core with as path loop prevention.

     

    anyhoo you can configure ip route profile and view with show ip route profile. Otherwise debug ip routing

  • It actually was in the core and i was surprised myself. I have even changed the layer 2 config so to be sure about the packet flow but this loop went up and i could not find the root. I did change wieght, LOCAL_PREF etc but it did not sort any good. In circa a hour back to config and to try to get this Lab 3 done. Thanks for your suggestion though. I did not think about ip route profile and i spent the last night studying on Jeff Doyle books loop mechanisms prevention and route tagging again !!!

     

    Alessio

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