I am hosting a website which will be accessed by the clients across the globle .I have router 3725 and links from diffrenet ISPs what kind of routes should I take from these ISPs so that My site will be accissible all the times if any one ISP fails...Should I take default routes from both ISPs? Thanks in advance
The default route from the ISP should be sufficient for multi-homing.
The important thing for multi-homing is having both ISPs announcing your public segment. One ISP will function as primary while having the other ISP as secondary.
It's up to the ISP how they want to manage the routing preference.
Thanks for your reply, So
1> I can take default routes from both the ISPs.
2> What things i need to keep in mind when configuring my router.
I have /24 network.
2. Which ISP you prefer as the primary. Local-preference is the attribute of choice in this kind of situation.
Since you have a /24 network, load sharing is not possible and the secondary link would be lying idle.
To avoid asymmetric routing Local Preference for outgoing traffic and AS-prepend for incoming.
If you have a /24 range, usually ISP will not advertise anything higher than a /24 range.
You can do outbound load SHARING using PBR, but for incoming traffic you will do a AS prepend for the entire /24 range and BGP will always select a single path.
LOAD SHARING WITH A /24 IS NO POSSIBLE FOR INCOMING TRAFFIC.
I am not aware of any link, but i can run you through the logic,
consider the following scenario
a/24 b/24 ISP1 ISP2
for a/24 pri would be ISP1 sec would be ISP2
for b/24 pri would be ISP2 sec would be ISP1
Rate if this helps.
In this case from which block I will use the IP address in router's inside Interface, FWs etc..will I use diffrenet matrics for this and what does it make difference for ISP other than they will publish my two networks