Framerelay interfaces are normally NBMA(Non-Broadcast Multiaccess) in nature.
Once a router interface/subinterface is configured as a Multipoint, automatically Split horizon is enabled.The reason is, since in multipoint the same intf/subinterface cannot send the data back through itself to reach another destination of this multipoint network.
If we treat a subinterface a P2P, then no problem, each subintf is treated as separate p2p link.That is data received on that subinterface p2p can be transmitted via the same sub intf to another destination which is also treated as p2p.
In short,a p2p int/subint -> split horizon is disabled (means split horizon issue is solved)
a p2MP int/subint - > splithorizon still holds true(the pblm is not solved and its enabled).
IS this correct, that both subints have split horizon enabled and the major interface disabled?
And the output of show ip interface provices a pretty direct answer that yes you are correct.
Looking at the original post I believe that this is about your discomfort that there is inconsistency between the behavior of the physical interface (multipoint with split horizon disabled) and the behavior of the multipoint subinterface (multipoint with split horizon enabled). Is that correct?
I do not know the authoritative explanation for this (perhaps some of the Cisco folk might fill it in) but have thought about it this way: If you just take simple defaults and use the physical interface, the DLCIs will default to being associated with the physical interface, it defaults to multipoint since there is the possibility of multiple DLCIs, and to protect those who are not doing much configuration Cisco turns off split horizon. When you are doing more configuration and are placing DLCIs where you want them (both for point to point and for multipoint) Cisco assumes that if you want split horizon disabled that you will do it yourself. They have provided an exception to the normal behavior of interfaces (by disabling split horizon) on the physical interface and have left the subinterfaces to conform with more normal behavior.
This is actually a pretty cool feature, i didn't even know it existed until I was looking for a solution to advertise a subnet (prefix in BGP talk), only if a certain condition existed. This is exactly what conditional advertisements does
j ai une question j ai achete un routeur cisco 887VA-k9 , je le configuré avec la configuration ci- dessous
si je le lier avec mon pc portable sur l un de ses ports directement ça marche toute est bien ( la connexion internet + m...
Attached policy provides CLI access to the Cisco 4G router over text messaging. Two files are in the attached .tar file:
2. PDF with instructions on how to load and use the .tcl file.