The BGP router preferred the route 30.30.30.0/24 from R2 in spite of it is a redistributed route from R4 it contradicts what you mentioned in the video, it should have selected the route from R1
Ha! You're absolutely correct, my apologies. The example should have shown that R4 used the "network" command and R3 used the "redistribute" command, then it would be correct. Thanks for pointing that out!
5:27 why Origin code is non-transient? RFC says "ORIGIN is a well-known mandatory attribute that defines the origin of the path information. " They mean the same thing?
Great question! The terms "non-transient" and "well-known mandatory" in the context of BGP attributes aren't exactly the same but are closely related. - Non-transient means the attribute is carried along unchanged as the route propagates through the network. It's not stripped or modified by intermediate routers unless there's a specific policy to do so. - Well-known mandatory means that the attribute must be recognized and included by all BGP speakers. It ensures the attribute is present in every BGP route advertisement. So, while "well-known mandatory" ensures the ORIGIN attribute exists in all BGP advertisements for all routes, "non-transient" ensures it remains consistent and unchanged as the route is propagated from router to router, from AS to AS. Both describe different aspects of the ORIGIN attribute's behavior, but they work together to ensure its reliability in BGP path selection. For more information about these characteristics, take a look at this video: ua-cam.com/video/9sHoHr82odQ/v-deo.htmlsi=uNO3HkAVIjQRcP9W
You said the i means route originated from IGP that is ospf or eigrp. But here you have used network command in BGP, so where the ospf and eigrp route comes into picture here?
Yes, this is a bit confusing, and it has to do with the terms used by BGP. You're absolutely correct, the "i" does stand for IGP and you would think that this would mean that the route has been learned from an IGP such as OSPF or EIGRP. But this is not the case! :P When you use the `network` command in a Cisco router to introduce a route into BGP, BGP will assign an origin code of "i" (IGP), even though it’s not actually sourced from an IGP. The "i" simply indicates that the route originated locally within the AS through the `network` command, as opposed to being learned from redistribution from a different protocol using the `redistribute` command. The terminology is confusing I agree, but it still stands that: - routes introduced using the `network` command get an origin of "i" - routes introduced using redistribution get an origin of "?" I hope this has been helpful!
Thank you for the insightful comment! You’re absolutely right that the default origin code behavior during redistribution can vary between vendors. For example, Cisco generally sets the origin code to incomplete when redistributing routes into BGP, as this aligns with the RFC 4271 definition. Other vendors might have configurable options or even different defaults. I'll consider adding this clarification to future videos-your feedback helps improve the content. 👍
Very nice explanation
Thanks for liking!
Appreciate your nice explanations. Good job, keep it going.
Thanks a lot!
Just wonderful
🤗
Beautiful!
Glad to hear it was helpful!
Very nice explanation!
Thanks!
The BGP router preferred the route 30.30.30.0/24 from R2 in spite of it is a redistributed route from R4 it contradicts what you mentioned in the video, it should have selected the route from R1
Ha! You're absolutely correct, my apologies. The example should have shown that R4 used the "network" command and R3 used the "redistribute" command, then it would be correct. Thanks for pointing that out!
5:27 why Origin code is non-transient? RFC says "ORIGIN is a well-known mandatory attribute that defines the
origin of the path information. " They mean the same thing?
Great question! The terms "non-transient" and "well-known mandatory" in the context of BGP attributes aren't exactly the same but are closely related.
- Non-transient means the attribute is carried along unchanged as the route propagates through the network. It's not stripped or modified by intermediate routers unless there's a specific policy to do so.
- Well-known mandatory means that the attribute must be recognized and included by all BGP speakers. It ensures the attribute is present in every BGP route advertisement.
So, while "well-known mandatory" ensures the ORIGIN attribute exists in all BGP advertisements for all routes, "non-transient" ensures it remains consistent and unchanged as the route is propagated from router to router, from AS to AS. Both describe different aspects of the ORIGIN attribute's behavior, but they work together to ensure its reliability in BGP path selection.
For more information about these characteristics, take a look at this video:
ua-cam.com/video/9sHoHr82odQ/v-deo.htmlsi=uNO3HkAVIjQRcP9W
You said the i means route originated from IGP that is ospf or eigrp. But here you have used network command in BGP, so where the ospf and eigrp route comes into picture here?
Yes, this is a bit confusing, and it has to do with the terms used by BGP. You're absolutely correct, the "i" does stand for IGP and you would think that this would mean that the route has been learned from an IGP such as OSPF or EIGRP. But this is not the case! :P
When you use the `network` command in a Cisco router to introduce a route into BGP, BGP will assign an origin code of "i" (IGP), even though it’s not actually sourced from an IGP. The "i" simply indicates that the route originated locally within the AS through the `network` command, as opposed to being learned from redistribution from a different protocol using the `redistribute` command.
The terminology is confusing I agree, but it still stands that:
- routes introduced using the `network` command get an origin of "i"
- routes introduced using redistribution get an origin of "?"
I hope this has been helpful!
Also could have made clear that the redistribution origin code differs from vendor to vendor. Not all vendors set the origin code to incomplete.
Thank you for the insightful comment! You’re absolutely right that the default origin code behavior during redistribution can vary between vendors. For example, Cisco generally sets the origin code to incomplete when redistributing routes into BGP, as this aligns with the RFC 4271 definition. Other vendors might have configurable options or even different defaults. I'll consider adding this clarification to future videos-your feedback helps improve the content. 👍