Assuming your EBGP isn't Internet, you might run both OSPF and IBGP on all four routers. All four then would "know" both inside and outside topologies and there would be no need to redistribute between OSPF and BGP.
If possible, would avoid preferred paths. Likely this could be supported via PBR, but often a maintenance headache. You could consider using OER/PfR on routers A and B so that, at least for outbound, best performance path would be chosen and/or dynamically load balance outbound links.
You could also consider using GLBP on LAN 6500s instead of HSRP.
"cant i achieve LB and failover using routing protocols, is it compulsory to use OEF/PfR"
No and no. (Note your first question was a negative.)
"i m not sure why to use both protocols on all 4 routers. can u pls ellaborate "
You don't have to run both protocols on all 4 routers. You will need to run EBGP on routers A and B, I assume, to peer with external provider routers. There's probably benefit to using OSPF for your internal routing protocol. If you're going to run both protocols, your left with the issue of making internal routes known to the routers A and B and BGP external routes known to 6500s A and B. There are different ways of doing this, usually doing some form of redistribution, or you could even use statics, but if you run both OSPF and BGP on all routers, all 4 routers will dynamically "know" both the inside and outside topologies.
If you use EBGP internally, one issue that might arrise is Cisco BGP's default of only placing one path in route table. You can adjust this using multipath, but not 100% certain IBGP will then automatically install multiple paths in route table.
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.