12-29-2007 11:29 PM
what are the main difference between various options of Inter AS MPLS VPN as well as what are the benifits of one over another?
01-03-2008 02:14 PM
The Inter-AS Hybrid for MPLS VPN over IP Tunnels feature allows a Multiprotocol Label Switching Virtual Private Network (MPLS VPN) to span autonomous systems (ASs) and VPN service providers when one of the VPN autonomous systems runs Layer 2 Tunneling Protocol version 3 (L2TPv3) in an MPLS VPN over IP Tunnels network. Following links may help you
http://www.cisco.com/en/US/tech/tk436/tk428/technologies_configuration_example09186a0080094472.shtml
http://www.cisco.com/en/US/products/sw/iosswrel/ps1829/products_feature_guide09186a00804bbd37.html
01-03-2008 03:18 PM
This is an area where you can write a book. but here is what i have for you so far:
- Back-to-back VRF
- MP-eBGP for VPNv4
- Multihop MP-eBGP
- Non-VPN transit Provider
Back-to-back VRF have Scalability is an issue with many VPNs, but it's the most secure Inter-AS. Also PE-ASBR must filter & store VPNv4 prefixes, Plus import into VRFs thus increasing MPLS, CEF & routing table memory
memory.
MP-eBGP for VPNv4:
MP-eBGP for VPNv4 prefix exchange. No LDP or IGP.
Next-hop and labels are rewritten when advertised across the Inter-Provider MP-eBGP session
*kind of downside* PE-ASBR stores all VPN routes which must be exchanged
No VRFs. Labels are populated into the LFIB of the PE-ASBR
Multihop MP-eBGP for VPNv4:
MPLS VPN providers exchange VPNv4 prefixes via their Route Reflectors, This frees the ASBR, and since the RR's already holding the Intra-AS VPNv4. This Improves the scalability of route exchange.
Non-VPN Transit Provider:
Two MPLS VPN providers may exchange routes one or more third party
Hope this helps.
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