Show IP BGP Information

jskfan
jskfan used Ask the Experts™
on
Show IP BGP Information

The Show IP BGP will show information about the Network(Routes), but there is a confusion about the "i" notation.

How do I know if the "i" is referring to:
Status Code: "Internal"

OR to:

Origin Code: IGP  
 

Thank you
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Alexey KomarovChief Project Engineer

Commented:
Hi,
i   iBGP
EBGP is peering between two different AS, whereas IBGP is between same AS (Autonomous System)
Distinguished Expert 2018

Commented:
i - does not mean iBGP - it is one of BGP attributes (origin) and can be manipulated. You can have i for networks that you received from any BGP router as description how network is advertised into BGP.

i - IGP - means that route is advertised into BGP by usage of network or aggregate-address command. At least that's is how it suppose to be. Since it is one of BGP attributes, it can be manipulated by route maps and to be changed to influence best path election.

Other possibilities are:
e - EGP -  protocol that was used before BGP (should not appear anymore - so it is for sure present by route-map manipulation of origin attribute)

? - INCOMPLETE - route is advertised into BGP by redistribution

Author

Commented:
when you run : Show IP BGP

Sometimes the "i" shows under "Network" column and sometimes shows under "Path" column, and sometimes under both columns.
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Distinguished Expert 2018
Commented:
Those are two different "i"

Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, <--- learned VIA iBGP
              r RIB-failure, S Stale

learned VIA iBGP AD [200/0] (does not mean that it is originated in the same AS (could be originated from other AS), just that it is learned from iBGP neighbor)
So Alexey Komarov was right for this part :) (I totally forgot about it).

Origin codes: i - IGP, e - EGP, ? - incomplete

s>i150.1.1.0/24     150.1.0.2                0    100      0 64512 i
learned via iBGP                                                                origin   i - IGP

Author

Commented:
the "i" under the column "Path"
means that the originating router had a network statement for that route.



the other "i", that rarely  shows under  the column "Network". I am not sure what causes it to show.
I want someone to elaborate on that.

Thanks
Alexey KomarovChief Project Engineer
Commented:
Hi,
This is a Status code
Status of the table entry. The status is displayed at the beginning of each line in the table. It can be one of the following values:
 s—The table entry is suppressed.
 d—The table entry is dampened.
 h—The table entry history.
 *—The table entry is valid.
 >—The table entry is the best entry to use for that network.
 i—The table entry was learned via an internal BGP (iBGP) session.
 r—The table entry is a RIB-failure.
 S—The table entry is stale.
 m—The table entry has multipath to use for that network.
 b—The table entry has a backup path to use for that network.
 x—The table entry has a best external route to use for the network.

Author

Commented:
I am not sure if you understood my question.
There are  2 types of "i"s
one of them is clear , it is  Origin code , and it will show up under "Path" column when you run show ip bgp command, that one means that the originating router used  a Network statement for that route.

the other "i" which is not clear , it is a Status code

If I remember it can show up under Network column(I could be wrong) , when you type show ip bgp command. I do not know what makes it show up ..
I want to know what will make it show up and whether it will show up under Network column as I am guessing.

Author

Commented:
probably if you have an example for both "i"s , that might make it clearer

Author

Commented:
the "i" under the column "Path"
means that the originating router had a network statement for that route.



I believe the other "i", that rarely  shows under  the column "Network".as you stated means
earned VIA iBGP AD [200/0] (does not mean that it is originated in the same AS (could be originated from other AS), just that it is learned from iBGP neighbor)

Author

Commented:
Thank you Guys

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