09-20-2008 03:02 PM
Hi,
I have the following scenario, please refer to the attachement.
There are basically 2 links from each site.
Site A - One active link is to ISP1 and the other link is a standby to ISP2.
Site B - One active link is to ISP2 and the other link is a standby to ISP1.
This topology is also replicated at sites C,D.
I am not really sure about the bgp config between the CEs and the PEs.
Any suggestions is very much appreciated.
Thanks.
Paul
09-21-2008 01:43 AM
Hello Paul,
when using two different ISPs two strategies are possible:
a) choice for all sites one ISP as primary and the other one as backup
b) tune the BGP config to use both ISP services
I don't think it is easy to have :
Site A: isp1 primary isp2 secondary
Site B: isp1 secondary isp2 secondary
for this to work this way the two ISPs must cooperate and setup inter-AS VPN, but from a redundancy point of view would be better if the two ISPs offer really separated services.
I would consider to modify this requirements.
Hope to help
Giuseppe
09-21-2008 01:53 AM
if u use VRFs on the PEs and all sites A,B,C and D in the same VRF/VPN then
the communication between each CE and its connected PE will be any routing protocol depends on the ISP mybe static route, mybe BGP or any IGP
within the provider network the PEs will redistribute this route into MP-BGP VPNv4
and vice versa
for example on PE1
router ospf 2 vrf CUSTA
log-adjacency-changes
redistribute bgp 1 subnets
network x.x.x.x y.y.y.y area 0
bgp 1
address-family ipv4 vrf CUSTA
redistribute ospf 2 vrf CUSTA match internal external 1 external 2
no synchronization
exit-address-family
if helpful Rate
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