Multicast over unicsat only network

[Ravindra Simpi]

Hello.

I need to create a single multicast packet to multiple unicast packets. The reason for this is; we have a unicast-only network between the source and receiver. While exploring the options to achieve this, I came accross AMT (Automatic IP multicast without explicit tunnel)

I want to convert multicast packet to nearly 1000 end users over a unicast only network and with 1600 different multicast streams.

rgds,

Ravindra

[lgijssel]

Your best option is to use GRE:

http://www.cisco.com/en/US/tech/tk827/tk369/tk287/tsd_technology_support_sub-protocol_home.html

Still it will be a very demanding solution where you need powerful devices and a clever design.

regards,

Leo

[Ravindra Simpi]

Hi,

lgijssel, I am not able to view the link you have shared.

[lgijssel]

This happens sometimes to partner links. When you have a CCO-id please login and try this one:

http://www.cisco.com/en/US/partner/tech/tk827/tk369/tk287/tsd_technology_support_sub-protocol_home.html

It's the GRE technology page, containing many links to GRE-related topics.

regards,

Leo

[Ravindra Simpi]

Ok, thanks.

I can have up to 1000 users per group. And up to 1600 multicast groups.

All the hosts will be connected to the unicast only network, and the core router will have just one interface towards the unicast-only network. Will I be able to create 1000 * 1600 gre tunnels?

Please see the attachment

[lgijssel · Accepted solution]

The idea is using GRE to span the unicast-only section of your network. This should not require 1000 * 1600 tunnels. In the worst case, it will be one tunnel per client doing multicast, regardless of the number of flows received by that client.

Taking several matters into consideration, a single GRE tunnel is capable of transporting many multicast flows.

Matters to consider are:

-Available Bandwidth

-Packet rates

-CPU load

Many routers can only perform GRE encapsulation in software, making them unsuited for high-volume traffic.

You need to select a device which can handle this in hardware. C7600 should be OK.

However, looking at you picture placing all receivers on the unicast-only net, it will be a very challenging design.

Bandwidth can become a serious problem because with 1000 receivers, each packet will be copied on the network 1000 times and that is only the first obvious problem. There will certainly be more. You need to have some real consultancy on the feasibility of this solution; as far as I'm concerned, things are not looking too wel.

regards,

Leo

[Ravindra Simpi]

Yes, I understand:

It is not just 1000 users for all the multicast groups. All the multicast groups may have 1000 different users.

That means atleast 100000 users will be interested in one or the other group. Bandwidth and CPU can be taken care of, and the question is, will the router support that many GRE tunnels at a single time?