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  1. Hi Rene,
    1st of all thank you for all of your precious writings.

    I started reading your BGP blog. But im struggling to find an easy way to start with BGP. Because topics are scattered all over the place. Can't figure out which topics I should read first. Can you please help and show me the correct order that i should follow to become a BGP guru.

    Thank you

  2. Hi Rene,
    Nice lessons on BGP !!
    Three questions.
    1. What is the significance of 32768 in the o/p given below for the local route?
    2. When will metric be non-zero for a given route in bgp?
    3. Is there a way to change the default admin distance of e BGP from 20 to a different value ?
    I believe admin distance is used to compare alternate paths for a given prefix from multiple sources ( directly connected, static, ospf etc..)
    Will I be able to change the order of priority for these sources for a given prefix?

    Emma#show ip bgp 
    BGP table version is 3, local router ID is 1.1.1.1
    Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
                  r RIB-failure, S Stale
    Origin codes: i - IGP, e - EGP, ? - incomplete
    
       Network          Next Hop            Metric LocPrf Weight Path
    *> 1.1.1.0/24       0.0.0.0                  0         32768 i
    *> 2.2.2.0/24       192.168.12.2             0             0 2 i
  3. Hi Ganesh,

    The 32768 is the weight, which is the maximum value. Weight is a Cisco proprietary BGP attribute that is on top of the list. The 1.1.1.0/24 prefix is advertised on this router so that's why you see the maximum weight value and a next hop of 0.0.0.0.

    The metric can be changed with a route-map, here's an example:

    https://networklessons.com/bgp/how-to-configure-bgp-med-attribute/

    The administrative distance can be changed yes, we use the AD when you have multiple sources advertising the exact same prefix:

    https://networklessons.com/ip-routing/administrative-distance-for-ccna-students/

    BGP allows fine control of choosing which prefixes you want to use, take a look at the "BGP Attributes" on this page:

    https://networklessons.com/bgp-lessons/

    Rene

  4. Hey Rene,

    I was trying to use the loopback address 1.1.1.0/24 on R1 to built IBGP with R2 and EBGP with R3 also. I tried but it is not working. Can we do like this??

  5. Hi,

    i configured bgp on both routers as you did before redistributing bgp routes.
    i recevied prefix in sh ip bgp summary

    emma#sh ip bgp sum
    BGP router identifier 1.1.1.1, local AS number 1
    BGP table version is 1, main routing table version 6
    0 network entries using 0 bytes of memory
    0 path entries using 0 bytes of memory
    0/0 BGP path/bestpath attribute entries using 0 bytes of memory
    0 BGP AS-PATH entries using 0 bytes of memory
    0 BGP route-map cache entries using 0 bytes of memory
    0 BGP filter-list cache entries using 0 bytes of memory
    Bitfield cache entries: current 1 (at peak 1) using 32 bytes of memory
    BGP using 32 total bytes of memory
    BGP activity 0/0 prefixes, 0/0 paths, scan interval 60 secs
    
    Neighbor        V    AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
    192.168.12.2    4     2       4       4        1    0    0 00:02:35        4

    but i can't see any prefix in your output.

    also can you explain what prefix signifies here.

    Thanks a ton for wonderful explanation.

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