Routing

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Ask questions and share experiences about ACX Series, CTP Series, MX Series, PTX Series, SSR Series, JRR Series, and all things routing, including portfolios and protocols.
  • 1.  multihop in ebgp

     
    Posted 08-03-2023 09:29

    Hi all,

    The following configuration on the MX device:

    Set protocols bgp group XXX type external
    Set protocols bgp group XXX multihop ttl 5
    Set protocols bgp group XXX local-add 10.10.10.10
    Set protocols bgp group XXX import WETLR_IN
    Set protocols bgp group XXX family inet unicast
    Set protocols bgp group XXX export WETLR_OUT
    Set protocols bgp group XXX peer-as XXX
    Set protocols bgp group XXX neighbor 192.168.20.40

    What is the multihop  in this conf? Why number of 5 is assigned to ttl ? What is the defaul value for the ttl in ebgp? what purpose can ttl be used? 

    thx

    A



  • 2.  RE: multihop in ebgp

    Posted 08-03-2023 09:32

    eBGP assumes that the two router neighbors are directly connected.  The multihop parameter allows you to have a neighbor that is NOT directly connected but is reached only through other routers.  The ttl limits how far apart the two neighbors can be.

    https://www.juniper.net/documentation/us/en/software/junos/bgp/topics/topic-map/multihop-sessions.html



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