1

In you case you want to get rid of the static default route and you want to peer with your single ISP, do you need to announce any routes for your side ? I have the below config, is it enough for peering with your ISP ?

ip prefix-list default permit 0.0.0.0/0

Router bgp xx

no auto-summary

no synchroniszation

Neighbor x.x.x.x remote-as ISP (peer to ISP)

Neighbor x.x.x.x password xxxx ( basic authentication)

Neighbour x.x.x.x prefix-list default in ( accept default only)
  • 2
    do you have an network to advertise to your ISP? If you have a single ISP, there's no point in "getting rid" of the default route since anyway all traffic will goes the the ISP. You add complexity and processing delay for no benefit. – JFL Apr 16 '18 at 8:51
  • Peering with ISP would make sens only if you are dual homed if I understand it right ? – Samirtow Apr 16 '18 at 8:54
  • Do you mean internet or MPLS? What static route are you referring to? – user36472 Apr 16 '18 at 9:09
  • Static default route to the internet, but as far as I understand, it doesnt make big sens to peer with your ISP if you are not dual homed. – Samirtow Apr 16 '18 at 9:27
  • You don't need a static default route, when the ISP announce it to you. – user36472 Apr 16 '18 at 10:36
4

There are generally two reasons to use BGP with your ISP:

  1. You have more than one connection to your ISP(s), and you want to influence which path your traffic takes.
  2. You have your own provider independent, registered block of IP addresses, which needs to be advertised.

For most organizations with a single connection to the Internet, there is no reason or advantage to run BGP with your provider. Since there is only one path to the Internet, a static default route is all you need. The ISP already announces their address blocks (of which you use a small part) to the Internet.

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