mohammedmahmoud Tue, 05/15/2007 - 10:36
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Hi,


In brief, the PE router runs iBGP with the ISP RR (Route Reflector), and also the ISP GW (Gateway) runs iBGP with the ISP RR, and thus each PE advertises the IP addresses of the customers attached to it, and finally the ISP GW runs eBGP with the internet backbone providers advertising all it's IP classes (Which is assigned from the RIR - Regional Internet Registry).


On the other hand the PE router and the CE router can have static or dynamic routing with each other (static, RIP, EIGRP, OSPF or eBGP).


The whole idea of MPLS is that the customer packets are label switched rather than routed on the ISP backbone.


I hope that i've been informative.



HTH, please do rate all helpful replies,

Mohammed Mahmoud.

mounir.mohamed Tue, 05/15/2007 - 18:15
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Dear,


The PE routers in any Service provider with MPLS Core network should be participating the ISP Core network this done by enable the MPLS tag switching on the PE outgoings interfaces facing the P routers, because inside the ISP core network all lookup and forwarding actions must be taken based on label header instead of the IP header,


also all PE routers running IBGP between each others or trough RR in order to provide internet and VPN services, the internet customers connected to the PE router and using the PE global routing table to reach the internet (BGP lead to the last resort gateway toward the internet)


PE routers doesn?t assign labels to BGP routes, the forwarding done by using the label assigned to the next-hop address attached with BGP entry which is mainly learned through the provider IGP, VPN customers using their VPN routing tables (VRF's). which is build up through CE-PE routing protocols and distributed via MP-BGP.


This is tow different applications of MPLS "MPLS Unicast and MPLS-VPN"


Please rate helpful posts


Best Regards,

Mounir Mohamed

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