how to rotate the ip address on a pool with overload nat translation

julio.fernandes_2 · ‎04-30-2010

Hello,

I have a catalist 6500 (sup 32) and i'm using User Based Rate Limit based on the source IP address.

I have a pool with 50 public address, with ovewrload.

How can i assign a diffrent IP address to each request, and only repeat the same address when it reaches the last one of the pool, instead of assign the same until the IP are saturated, with about 4000 translations?

Or change the limit of overload translations for the same IP?

Or distribute the assignments equaly for every IP on the pool?

Or assign a ip from the pool based on a random algoritm?

Or other mothod to distribute the requests from all the pool and not only the first one (or last one).

Tanks

Luís Pisco

Ganesh Hariharan · ‎05-01-2010

Hello,

I have a catalist 6500 (sup 32) and i'm using User Based Rate Limit based on the source IP address.

I have a pool with 50 public address, with ovewrload.

How can i assign a diffrent IP address to each request, and only repeat the same address when it reaches the last one of the pool, instead of assign the same until the IP are saturated, with about 4000 translations?

Or change the limit of overload translations for the same IP?

Or distribute the assignments equaly for every IP on the pool?

Or assign a ip from the pool based on a random algoritm?

Or other mothod to distribute the requests from all the pool and not only the first one (or last one).

Tanks

Luís Pisco

Hi Luis Pisco,

Basically NAT overload sometimes called PAT (Port Address Translation) maps multiple unregistered or private IP addresses to a single registered or public IP address by using different ports. As NAT processes each packet, it uses a port number to identify the packet source - 2333 and 1555

So with Nat Overload configured you can have a single ip serving for multiple private ip adress based on the available ports.

Dynamic NAT on the other hand maps private IP addresses to public addresses. Dynamic NAT uses a pool of public addresses and assigns them on a first-come, first-served basis. When a host with a private IP address requests access to the Internet, dynamic NAT chooses an IP address from the pool that is not already in use by another host. Dynamic NAT is useful when fewer addresses are available than the actual number of hosts to be translated.

Hope to Help !!

Ganesh.H

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julio.fernandes_2 · ‎05-04-2010

Hello,

I know how NAT overload (or PAT) and dynamic NAT works.

I have a big IP pool with dynamic NAT, maping one internal IP to one external IP.

That part its working.

But I'm assigning diferent IP's pool based on route map, to diffrent sources IP.

On the second pool I have 50 public IP, and about 10000 potencial users, so i have to use overload.

But, because i have flow rate limit (UBRL) based on the destination IP for the internet download, i want the NAT overload to assign IP on a rotary base, or random, to have about the same number of connections/users on each public IP.

For example, if i have 1000 NAT users on a 50 IP pool, i want to have 1000/50=20 private IP for each public IP.

I have a rate limit for each public IP of 20Mbit. If the NAT assign only one IP, the total users (1000 on the example) will have only 20Mbit, instead of 20Mbit for each group of 20 users (on the example).

I think the question is better understood now. Sorry if not.

Tanks

Luis Pisco