BGP questions

Unanswered Question
May 20th, 2008
User Badges:

Guys we use static routes in bgp??? like what ar ethe things which force us to use static routes.....secondly when we put network under bgp command like bgp 123 netwrok so the router starts advertising the network to its peer?? am i right? just like other routing protocols? thridly what eigrp and ospf uses as its transport layer protocol like bgp uses 179? which ports other routing protocols uses....guys thanks a million in advance

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 5 (2 ratings)
Jon Marshall Tue, 05/20/2008 - 23:27
User Badges:
  • Super Blue, 32500 points or more
  • Hall of Fame,

    Founding Member

  • Cisco Designated VIP,

    2017 LAN, WAN

Static routes in BGP can be used to advertise out networks. For example if you have under your BGP config

router bgp 65321

network mask

and in your routing table you have

then it will not be advertised out because BGP needs an exact match in the IGP routing table to advertise a route out from it's network statement. So you could put

ip route Null0

into the IGP table and then BGP would advertise it out. Alternatively you could just not include the "mask" part of the network statement and then as long as there is a part of the route in routng table it will be advertised out (thanks to Victor for pointing that last bit out).

You are correct in that if you have

router bgp 65321


then BGP will advertise this network out to other peers (subject to above provisos).

However this is not how IGP routing protocols (RIP/EIGRP/OSPF) work. For example

router eigrp 1


This does not tell EIGRP to advertise out network What it does do is tell the router to start running EIGRP on any interface that has an ip address out of the subnet.

EIGRP & OSPF work at L3 of the OSI model. They have their own IP protocol numbers



so they do not have a TCP port number.


lamav Wed, 05/21/2008 - 18:17
User Badges:
  • Blue, 1500 points or more

Jon specializes in 'lovely.' :-)

Rated your post, Jon....I loved it.



This Discussion