- Green, 3000 points or more
Hi all ,
Could someone give me some insight/ideas in giving various options in this particular scenario/project ?
Today I learned we are upgrading our current T1 out to the internet with a DS3, but we are not using the same ISP but rather a completely new ISP provider, which means we must change our public IP block needless to say our current IP block is used to allow our clients to connect to our DMZ servers . I have began researching how to go about this migration, whether to implement a parallel internet edge using 2 ISPs but the end state will be to remove the old ISP.. so I don?t know what will be the best way to approach this migration with minimal impact and a fall back , if we should configure/implement a multihoming secenario or just simply a hot cutover , if multihoming was to be implemented how to go about having all internal default route using the new ISP while having the old ISP functional while the new IP block from new ISP is integrated in our firewalls new global NAT pools etc.. , how could I logically route the new ISP IP block into our PIX515s external interface on top our current ISP, and have the default route go out the new ISP .
If a hot cutover is to be implemented would like to have some examples of fallback into the old ISP in case things go wrong.
This the current edge physical/logical setup for our internet gateway .
Edge router running two routing protocols BGP and OSPF
EDGE-router serial interface peers with ISP ( BGP )
EDGE-router FE interface connects to external switch vlan to PIX515e (outside interface) participating in OSPF .
PIX515e v.6.3(3) currently holds 4 other FE interfaces by which all 4 FE are all utilized for DMZ purposes . PIX running two OSPF processes, one for PIX-outside interface (public side ) to EDGE-router and a second OSPF process for the PIX-inside interface OSPF inside area.
Ospf default route or gateway of last resort is injected downstream to other ospf inside neighbors throughout our LAN from the EDGE-router?s OSPF process.
New ISP is providing us with the router and DS3 link , so most likely we will do BGP peering.
Some examples in migrating ISPs or multihomming links would greatly be appreciated.