So, the ISP has agreed to replace our current 2MB x 2 Serial WAN links of xDSL technology to 4MB x2 links, probably MPLS based Ethernet offering from their side.
The links are basically used for Internet based http/SMTP traffic.
In the old scenario, we utilised our 2MB x 2 links by bringing them both into serial interfaces of our 1800 router while the iSP did simple packet switching from their side while we ran IP CEF on our router. In case one line failed, we had a fallback of 2 MB. The FE interface was connected to PIX side.
Now, in the new scenario, the ISP techies are saying that the two new 4MB x 2 links will terminate on a new 2811 router having 4 Ethernet interfaces. They will run SVI on two of the FE interfaces as our 2811 HWIC doesn't support 4 individual real WAN IPs.
Also, in order to give us a combined bandwidth of 4MB x 2 links, they will run BGP on their side of the routers and also on our 2811.
1. Is this the correct way to deploy 4Mb x 2 WAN links? Do I really get a combined bandwidth of 8MB, both inwards and outwards.
2. What would be the effect of running BGP on our side of the router? With 64 MB of onbaord RAM, is this doable?
3. Is it better to keep 4MB live and keep the other 4 MB as backup and run some sort of OSPF for failover?
Any other ideas?
PS: For some reason, the ISP is unwilling to give an 8MB, single line to make things easier for us.