Seamless MPLS explained in 10 minutes | What is Seamless MPLS | How does Seamless MPLS work

[@tolgayucel1442]

Thank you so much, it is one of the best and the most clear explanation of Seamless MPLS

[@ping-factory]

Glad you think so!

[@amalouomar3609]

Thanks , very good job and very clear explanation ❤

[@ping-factory]

You are welcome!

[@jeremyshao9141]

so what about if the core has a RR, so all ABRs in the core network establish a BGP-LU session with the RR ?

[@arvindsingh-qs9kk]

Excellent explanation

[@AbhijeetKumar03]

Will label be regenerated for IBGP on ABR ?

[@luismayork]

Beatifull explanation !

[@luismayork]

I wonder , how SR MPLS can resolve the same situation , have you any other video when you explain this , whit SR mpls ? Thanks in advance.

[@Foxlaren]

Thankyou well explained, please also make a video on BGP-LU as u mentioned.

[@ping-factory]

Thanks! BGP-LU is in plan, yes.

[@mcgreenning]

Thank you for your difficult work. I have a question - does the scheme provide for the possibility of direct communication between regions? As a protection route, for example. Thank you.

[@ping-factory]

Sure, you could have a router that runs both regions processes. It would then run BGP-LU and forward the BGP-LU advertisement from 1 PE to the other. Quite hard to explain just in writing :) Anyway, this wouldn't scale also. Big SP's have like tens of regions, directly connecting each region to each other is almost impossible.

[@felixruiztorrez5192]

Hello. In the Alcatel-Lucent Versatile Routing and Services with BGP book by Bookham, mentions that there shouldn't be direct communication between aggregation regions, instead it should go through the core.

[@ping-factory]

@@felixruiztorrez5192 yes, this is correct. This is how it should be done in real world networks, but in the lab you can do anything you wish. And what I was saying before was that we could have direct communication between regions. It would work from a protocol perspective, but it beats the whole purpose of segmentation per regions.

[@joanelietheiligerruiz3144]

Gracias !!!!!

[@PiotrBawolik]

Your example is wrong. Seamless MPLS can be used only with OSPF, not with ISIS. I can explain. The ISIS connection between R3(P) and R4(ABS) is Level 2 connection, because only Level 2 connection could be used with 2 different areas. That means that R3 is L1/L2 router, so he KNOW the path to 9.9.9.9 without BGP. And you will run LDP only within each IGP domain there woulnd be a LSP from R1 to R4 (i mean, if you use ISIS).

[@ping-factory]

Hey! The trick is that you run different ISIS processes in each IGP domain, not different areas/levels. You don't redistribute between the processes so you don't leak prefixes between the IGP domains.