By default I understand that IBGP should have a full mesh implementation, otherwise route reflectors should be configured while EBGP should be directly connected to establish external neighbor, but how does BGP prevents loops by its default behavior, and how does BGP prevents slow peer and troubleshooting for this scenario?

Furthermore, does BGP dynamically advertise its routes like OSPF or the network statement command should be configured?

1 Answer 1


The BGP rule is that iBGP cannot learn an iBGP-learned route from an iBGP neighbor. That is a loop prevention mechanism. BGP will not use a route with its own AS in the AS_PATH.

I don't understand this question:

how does BGP prevents slow peer and troubleshooting for this scenario?

BGP can use redistribution, like other routing protocols, or it can use network statements, which simply tells BGP to advertise a route if that exact route exists in the router's routing table. You cannot simply add a network statement and assume BGP will advertise that prefix.

Yes, BGP advertisements are dynamic, like other routing protocols. As routes come into or leave the routing table, routes will be advertised or withdrawn, assuming proper redistribution or network statements are configured for the routes.

  • Hi to re phrase the question - How does BGP prevents slow peer and troubleshooting for this scenario? When peering with an EBGP neighbor PE router, what are the general troubleshooting process in dealing with slow BGP connectivity or does BGP by default through its attributes will deal with slow connectivity dynamically.
    – user39946
    Sep 14, 2017 at 17:50
  • I don't know what you mean by, "slow BGP connectivity." It is what it is. BGP sets up a TCP connection between the peers, and it exchanges prefixes on that connection.
    – Ron Maupin
    Sep 14, 2017 at 17:59
  • Hi Ron, thank you for the answers, I was asking on a live environment on a service provider level does BGP ever encounter slow connectivity? I am actually working with BGP on an enterprise level - peering with our MPLS PE router.
    – user39946
    Sep 14, 2017 at 18:20
  • As with any network connection, you can have slow connectivity. This can happen with any type of traffic, including routing protocols. This can cause routes to be advertised and withdrawn, or it could break a TCP (BGP) connection. You will experience a lot of other problems with the connection, too, and you would need to deal with it (bandwidth upgrade QoS, etc.). This is really too broad for the this site. If you have a specific question, we could try to answer it, but the concept of slow connectivity is far too broad to deal with here.
    – Ron Maupin
    Sep 14, 2017 at 18:24

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