jskfan
asked on
BGP Code
BGP code
in the screenshot below, we can see the character "i" , under Network column and on the far right side by Path column
Well...if I understand the "i" in far right side, means the route has been advertised by Network command
what about the one under Network column for instance:
* i10.5.1.0/24
Thank you
in the screenshot below, we can see the character "i" , under Network column and on the far right side by Path column
Well...if I understand the "i" in far right side, means the route has been advertised by Network command
what about the one under Network column for instance:
* i10.5.1.0/24
Thank you
ASKER
I set up a BGP LAB as shown in the topology... Ignore R5 as it is just like R3 in matter of configuration
Well I have connectivity from end to end , I can ping any router interface from any router.
I have not used any IGP (EIGRP,OSPF,RIP), just plain BGP.
I still cannot get the grasp of the "i" on the left and the "i" on the right
Well I have connectivity from end to end , I can ping any router interface from any router.
I have not used any IGP (EIGRP,OSPF,RIP), just plain BGP.
I still cannot get the grasp of the "i" on the left and the "i" on the right
R1#sh ip bgp
Network Next Hop Metric LocPrf Weight Path
*>i3.3.3.3/32 10.0.0.2 0 100 0 3000 i
* i10.0.0.0/24 10.0.0.2 0 100 0 i
*> 0.0.0.0 0 32768 i
* i20.0.0.0/24 20.0.0.4 0 100 0 i
*> 0.0.0.0 0 32768 i
*>i30.0.0.0/24 10.0.0.2 0 100 0 i
R2#sh ip bgp
Network Next Hop Metric LocPrf Weight Path
*> 3.3.3.3/32 30.0.0.3 0 0 3000 i
* i10.0.0.0/24 10.0.0.1 0 100 0 i
*> 0.0.0.0 0 32768 i
*>i20.0.0.0/24 10.0.0.1 0 100 0 i
*> 30.0.0.0/24 0.0.0.0 0 32768 i
R3#sh ip bgp
Network Next Hop Metric LocPrf Weight Path
*> 3.3.3.3/32 0.0.0.0 0 32768 i
*> 10.0.0.0/24 30.0.0.2 0 0 1000 i
*> 20.0.0.0/24 30.0.0.2 0 1000 i
r> 30.0.0.0/24 30.0.0.2 0 0 1000 i
[
R4#sh ip bgp
Network Next Hop Metric LocPrf Weight Path
*>i3.3.3.3/32 10.0.0.2 0 100 0 3000 i
*>i10.0.0.0/24 20.0.0.1 0 100 0 i
* i20.0.0.0/24 20.0.0.1 0 100 0 i
*> 0.0.0.0 0 32768 i
*>i30.0.0.0/24 10.0.0.2 0 100 0 i
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ASKER
correct, I used Network command to advertised the networks
the link you posted does not explain the meaning of "i" that you see sometimes under Network column , example:
*>i3.3.3.3/32
Well, in my case I did not have to use any IGP(RIP,EIGRP,OSPF) and managed to get connectivity from End to END.
So when does IGP get involved, or we 'll have to use it ?
Thank you
the link you posted does not explain the meaning of "i" that you see sometimes under Network column , example:
*>i3.3.3.3/32
Well, in my case I did not have to use any IGP(RIP,EIGRP,OSPF) and managed to get connectivity from End to END.
So when does IGP get involved, or we 'll have to use it ?
Thank you
As you have not redistributed into IGP then it doesn't. The i that appears under the Network section of the table refers the it being internally learnt. This is detailed in the article that I suggested. I did note that it was only partially accessible when I rechecked it. When I initially read it, I could see the full article.
ASKER
3.3.3.3 is a loopback address of R3 which is in AS 3000
if you take a look at the show BGP output posted above
it shows as the Best route in every router BGP table. However there is an "i" under column on R4 and R1 only, but not on R2 and R3
how do you explain that ?
if you take a look at the show BGP output posted above
it shows as the Best route in every router BGP table. However there is an "i" under column on R4 and R1 only, but not on R2 and R3
how do you explain that ?
ASKER
I guess I managed to understand it.
the "i" under Network column, Will Not show up when the route has come from that same router ex: 3.3.3.3 is on R3
OR
the route is received by the Edge router of a different AS R2 (1000)
in our case:
3.3.3.3 is on R3 As 3000 and the Edge router R2 AS 1000 has directely received the route from R3 AS 3000. so "i" will not show up on R3 and R2
R1 and R4 have received the route 3.3.3.3 via a router within their AS 1000, and the "i" will show up.
R1 received 3.3.3.3 from R2 (which is in the same As 1000) and R4 received 3.3.3.3 from R1 (which is in the same AS 1000)
the "i" under Network column, Will Not show up when the route has come from that same router ex: 3.3.3.3 is on R3
OR
the route is received by the Edge router of a different AS R2 (1000)
in our case:
3.3.3.3 is on R3 As 3000 and the Edge router R2 AS 1000 has directely received the route from R3 AS 3000. so "i" will not show up on R3 and R2
R1 and R4 have received the route 3.3.3.3 via a router within their AS 1000, and the "i" will show up.
R1 received 3.3.3.3 from R2 (which is in the same As 1000) and R4 received 3.3.3.3 from R1 (which is in the same AS 1000)
ASKER
What I need to understand, is when should we use IGP (RIP,EIGRP,OSPF) in order to get the BGP routes in each router of an AS
in my topology above , I do not have Full mesh in AS 1000. if I had full mesh between the 3 routers or 4 routers in the same AS. should I configure IGP in order to get BGP routes known by each router on the same AS 1000, or there is no needs to do that ?
in my topology above , I do not have Full mesh in AS 1000. if I had full mesh between the 3 routers or 4 routers in the same AS. should I configure IGP in order to get BGP routes known by each router on the same AS 1000, or there is no needs to do that ?
A BGP AS needs a full mesh to function.
It's only reference, but you might want to take a look here:
http://www.bgpexpert.com/bgpanswers.php
It's only reference, but you might want to take a look here:
http://www.bgpexpert.com/bgpanswers.php
ASKER
on my topology above I did not have full mesh and it worked.
the only down side I see.. is the fault tolerance path...any router that fails, BGP will not function through the network, there is only one path from end to end
the only down side I see.. is the fault tolerance path...any router that fails, BGP will not function through the network, there is only one path from end to end
ASKER
Thank you
:-)
Under Network I would interpret the *i as: valid, i( internal )BGP and on the right side of the table I would interpret the i as referring to IGP.
Kind regards,
David