I am new to BGP and have a question about redundancy.
It's my understanding that I can get a T1 from two different ISP's and setup BGP to propagate a route to my network to both ISP's core routers.
Hopefully I am correct so far?
My question is our current public IP block was assigned to us by Sprint. If I get a backup T1 through AT&T, can I propagate a route to my Sprint IP block to AT&T's routers so it comes in on the AT&T circuit?
We recently had a Sprint outage and realized we depend to heavily on a single carrier. We want our website to have redundancy via another carrier.
Another question I have is, assuming the above works, should my Sprint T1 go down, how long does it typically take for the core routers to realize it needs to go to AT&T to get to me?
Without knowing your addressing it's difficult to say but the main problem is that the block of IP addresses assigned to you by Sprint will be part of a bigger block of addressing that Sprint owns.
So Sprint will not be advertising your individual addressing to the rest of the internet rather they will advertise their aggregate block of which you addressing is part.
Even if you could get AT&T to agree to advertise out your Sprint addressing, and they may not as ISP have restrictions on this, your addressing would be advertised out by AT&T as your individual block because it's not part of their aggregate block.
So now all traffic coming to you will go via AT&T because they are advertising a more specific route to your networks.
If you could persuade Sprint to also advertise out your individual block of addressing then you would be okay but ISP's are generally very unwilling to "punch" holes in their aggregate addressing for individual customers.
They require you to justify the class C but filling out forms and showing that you will use it. You also have to do some testing to make sure the traffic doesn't come in the other link (not sure if this would cause problems for you) because I have learned that some providers might actually have a shorter route through the second ISP. For me the prepending solution seems to work, though I am still working out the kinks. Hope this helps. I can post here or contact you with other information, as I am in the same process, just a few steps ahead of you. :)
This is actually a pretty cool feature, i didn't even know it existed until I was looking for a solution to advertise a subnet (prefix in BGP talk), only if a certain condition existed. This is exactly what conditional advertisements does
j ai une question j ai achete un routeur cisco 887VA-k9 , je le configuré avec la configuration ci- dessous
si je le lier avec mon pc portable sur l un de ses ports directement ça marche toute est bien ( la connexion internet + m...
Attached policy provides CLI access to the Cisco 4G router over text messaging. Two files are in the attached .tar file:
2. PDF with instructions on how to load and use the .tcl file.